relay CHRYSLER VOYAGER 2001 Service Manual

1.0 INTRODUCTION
The procedures contained in this manual include
all of the specifications, instructions, and graphics
needed to diagnose 41TE/AE Electronic Automatic
Transaxle (EATX) problems. The diagnostics in this
manual are based on the failure condition or symp-
tom being present at the time of diagnosis.
When repairs are required, refer to the appropri-
ate volume of the service manual for the proper
removal and repair procedure.
Diagnostic procedures change every year. New
diagnostic systems may be added and/or carryover
systems may be enhanced. READ THIS MANUAL
BEFORE TRYING TO DIAGNOSE A VEHICLE
TROUBLE CODE. It is recommended that you
review the entire manual to become familiar with
all new and changed diagnostic procedures.
This book reflects many suggested changes from
readers of past issues. After using this book, if you
have any comments or recommendations, please fill
out the form at the back of the book and mail it back
to us.
1.1 SYSTEM COVERAGE
This diagnostic procedures manual covers all
2001 RG equipped with a 41TE/AE transaxle.
1.2 SIX -STEP TROUBLESHOOTING
PROCEDURE
Diagnosis of the 41TE/AE electronic transaxle is
done in six basic steps:
verification of complaint
verification of any related symptoms
symptom analysis
problem isolation
repair of isolated problem
verification of proper operation
2.0 IDENTIFICATION OF
SYSTEM
RG series vehicles equipped with a 4 speed trans-
mission.
3.0 SYSTEM DESCRIPTION AND
FUNCTIONAL OPERATION
3.1 GENERAL DESCRIPTION
The 41TE/AE electronic transaxle is a conven-
tional transaxle in that it uses hydraulically ap-
plied clutches to shift a planetary gear train. How-
ever, the electronic control system replaces many of
the mechanical and hydraulic components used in
conventional transmission valve bodies.
3.2 FUNCTIONAL OPERATION
The 41TE/AE electronic transaxle has a fully
adaptive control system. The system performs it's
functions based on continuous real-time sensor
feedback information. The control system automat-
ically adapts to changes in engine performance and
friction element variations to provide consistent
shift quality. The control system ensures that clutch
operation during upshifting and downshifting is
more responsive without increased harshness.
The Transmission Control Module (TCM) contin-
uously checks for electrical problems, mechanical
problems, and some hydraulic problems. When a
problem is sensed, the TCM stores a diagnostic
trouble code. Some of these codes cause the tran-
saxle to go into limp-in or default mode.
While in this mode, electrical power is taken
away from the transaxle via the TCM, de-
energizing the transmission control relay, and tak-
ing power from the solenoid pack. When this hap-
pens, the only transaxle mechanical functions are:
Park and Neutral
Reverse
Second Gear
No upshifts or downshifts are possible. The posi-
tion of the manual valve alone allows the three
ranges that are available. Although vehicle perfor-
mance is seriously degraded while in this mode, it
allows the owner to drive the vehicle in for service.
Once the DRBIIItis in the EATX portion of the
diagnostic program, it constantly monitors the
TCM to see if the system is in limp-in mode. If the
transaxle is in limp-in mode, the DRBIIIž will flash
the red LED.
3.2.1 AUTOSTICK FEATURE
This feature allows the driver to manually shift
the transaxle when the shift lever is pulled back
into the AutoStick position. When in AutoStick
mode, the instrument cluster displays the current
gear.
1
GENERAL INFORMATION

PRESENT'' and the reset counter will show
``STARTS SINCE CLEAR = XXX''.
The number of starts helps determine if the
diagnostic trouble code is hard or intermittent.
± If the count is less than 3, the code is usually a
hard code.
± If the count is greater than 3, it is considered
an intermittent code. This means that the
engine has been started most of the time
without the code recurring.
3.3.5 TROUBLE CODE ERASURE
A Diagnostic trouble code will be cleared from
TCM memory if it has not reset for 40 warm-up
cycles.A warm-up cycle is defined as sufficient vehicle
operation such that the coolant temperature has
risen by at least 4.4C (40ÉF) from engine starting
and reaches a minimum temperature of 71C
(160ÉF).
The Malfunction Indicator Lamp (MIL) will turn
off after 3 good trips or when the DTC's are cleared
from the TCM.
3.3.6 LIST OF DIAGNOSTIC TROUBLE
CODES
(Detailed descriptions follow list)
The TCM may report any of the following DTC's.
DTC P-Code Name of Code Limp-in MIL
11 P0700 Internal TCM Yes Yes
12 P1792 Battery was disconnected No No
13 P0700 Internal TCM Yes Yes
14 P1767 Relay output always on Yes Yes
15 P1768 Relay output always off Yes Yes
16 P0605 Internal TCM Yes Yes
17 P0604 Internal TCM Yes Yes
18 P0725 Engine speed input circuit Yes Yes
19 P1716 Bus communication with engine module No No
20 P1765 Switched battery (Trans Relay Output) Yes Yes
21 P1781 OD pressure switch sense circuit Yes Yes
22 P1782 2-4 pressure switch sense circuit Yes Yes
24 P1784 L-R pressure switch sense circuit Yes Yes
28 P0705 Check shifter signal No No
29 P0120 Throttle position sensor signal circuit No No
31 P1787 OD hydraulic pressure switch circuit Yes Yes
32 P1728 24 hydraulic pressure switch circuit Yes Yes
33 P1728 OD/24 hydraulic pressure switch circuit Yes Yes
35 P1791 Loss of prime No No
36 P1790 Fault immediately after shift No No
37 P1775 Solenoid switch valve latched in TCC position No Yes
38 P0740 Torque converter clutch control circuit No Yes
45 P1795 Internal TCM No No
47 P1776 Solenoid switch valve latched in L-R position Yes Yes
48 P1793 TRD link communication error No No/Yes (3.3L-3.5L)
50 P0736 Gear ratio error in reverse Yes Yes
51 P0731 Gear ratio error in 1st Yes Yes
52 P0732 Gear ratio error in 2nd Yes Yes
53 P0733 Gear ratio error in 3rd Yes Yes
54 P0734 Gear ratio error in 4th Yes Yes
56 P0715 Input speed sensor error Yes Yes
57 P0720 Output speed sensor error Yes Yes
58 P1794 Speed sensor ground error Yes Yes
70 P1796 Autostick sensor circuit No No
4
GENERAL INFORMATION

DTC P-Code Name of Code Limp-in MIL
71 P1797 Manual shift overheat No No
73 P1798 Worn out/burnt transmission fluid No No
74 P1799 Calculated Oil temperature in use No No
75 P1738 High temperature operation activated No No
76 P1739 Power up at speed No No
77 P1717 No communication with the MIC No No
78 P0600 Serial communication link malfunction No No
79 P1714 Low battery voltage Yes Yes
Yes (underlined) indicates that this DTC can take up to five minutes of problem identification before
illuminating the MIL.
3.3.7 DTC DESCRIPTIONS
Name of code:P1792(12) - Battery was Discon-
nected (Informational code Only)
When monitored:Whenever the key is in the
Run/Start position.
Set condition:This code is set whenever the
Transmission Control Module (TCM) is discon-
nected from battery power (B+) or ground. It will
also be set during the DRBIIItBattery Disconnect
procedure.
Theory of operation:A battery backed RAM
(Random Access Memory) is used to maintain some
learned values. When the battery B(+) is discon-
nected, the memory is lost. When the B(+) is re-
stored, this memory loss is detected by the TCM.
The code is set and the learned values are initial-
ized to known constants or previously learned val-
ues from EEPROM (Electronic Erasable Program-
mable Read Only Memory). This results in the
initialization of some parameters.
Transmission Effects:Loss of trouble code data.
Immediate limp-in mode if power is lost while
operating the vehicle. Normal operation is resumed
if the power is restored during the same key start.
Possible causes:
> Battery voltage removed from TCM
> TCM disconnected
> Dead Battery
> Low battery voltage during cranking
> Battery Disconnect by DRBIIItor MDS
> Bad TCM ground circuit.
Name of code:P1767(14) - Relay Output Always
On
When monitored:Ignition key is turned from off
position to run position and/or ignition key is
turned from crank position to run position.
Set condition:This code is set if the Transmission
Control Module (TCM) senses greater than 3 voltsat the Trans Relay Output (switched battery) ter-
minal of the TCM prior to the TCM energizing the
relay.
Theory of operation:The transmission control
relay is used to supply power to the solenoid pack
when the transmission is in normal operating
mode. When the relay is off, no power is supplied to
the solenoid pack and the transmission is in limp-in
mode. The relay output is fed back to the TCM
through pins 16 and 17. It is referred to as the
Trans Relay Output circuit or switched battery.
Transmission Effects:The MIL will illuminate
and the transmission system defaults to Logical
limp-in mode. Logical Limp-in mode results in the
same modes of operation as Relay Open Limp-in.
Since the relay is stuck9on9, the TCM can not open
the relay, and the TCM shifts to 2nd gear.
Possible causes:
> Relay failure (welded contacts)
> Short to battery in 12-volt supply and/or Trans-
mission Control Relay Output circuit(s)
> Short to voltage
> TCM connector problems
> TCM
Name of code:P1768(15) - Relay Output Always
Off
When monitored:Continuously
Set condition:This code is set when less than 3
volts are present at the Trans Relay Output
(switched battery) terminals at the Transmission
Control Module (TCM) when the TCM is energizing
the relay.
Theory of operation:The transmission control
relay is used to supply power to the solenoid pack
when the transmission is in normal operating
mode. When the relay is off, no power is supplied to
the solenoid pack and the transmission is in limp-in
mode. The relay output is fed back to the TCM
through pins 16 and 17. It is referred to as the
Trans Relay Output circuit or a switched battery.
5
GENERAL INFORMATION

After a controller reset (ignition key turned to the
run position or after cranking engine), the control-
ler energizes the relay. Prior to this the TCM
verifies that the contacts are open by checking for
no voltage at the switched battery terminals. After
the relay is energized, the TCM monitors the ter-
minals to verify that the voltage is greater than 3
volts.
Transmission Effects:The MIL illuminates and
the transmission system defaults to Relay Open
limp-in mode.
Possible causes:
> Relay failure (intermittent relay function caused
by oxidized or contaminated relay contacts)
> Short to ground or open circuit in the Transmis-
sion Control Relay circuit(s)
> TCM connector problem
> TCM
Name of code:P0725(18) - Engine Speed Sensor
Circuit
When monitored:Whenever the engine is run-
ning.
Set condition:This code is set when the engine
speed sensed by the Transmission Control Module
(TCM) is less than 390 RPM or greater than 8000
RPM for more that 2.0 seconds.
Theory of operation:The TCM uses either a
EATX RPM signal (simulated Crank Sensor signal)
or the TCM uses the Crank Postion Sensor signal to
calculate engine RPM depending on the engine
application. The signal supplied by the PCM and
uses a dedicated circuit is called the EATX RPM
Signal circuit. The Crank Position Sensor signal is
a spliced circuit from the engine Crank Position
Sensor. If the TCM interprets this signal to be out of
range when the engine is running (as reported by
the PCM over the bus) the code is set.
Transmission Effects:The MIL illuminates and
the transmission system defaults to Relay Open
limp-in mode.
Possible causes:
> Open or short in EATX RPM Signal circuit. (3.5L)
> Open or short in Crank Position Sensor Signal
circuit. (3.3L/3.8L)
> Open or short in Crank Position Sensor ground
circuit. (3.3L/3.8L)
> TCM and/or PCM connector problems
> TCM
> PCMName of code:P0716(19) - Bus Communication
with Engine Module
When monitored:Continuously with key on.
Set condition:If no PCI bus messages are received
from the Powertrain Control Module (PCM) for 10
seconds.
Theory of operation:The TCM communicates
with the PCM using the PCI bus. It relies on certain
information to function properly. The TCM contin-
uously monitors the PCI bus to check for messages
broadcast from the PCM.
Transmission Effects:Delayed 3-4 shifts. No
EMCC and early 3-4 shifts for a few minutes after
engine is started.
Possible causes:
> Open or shorted PCI bus circuit
> TCM
> PCM
Name of code:P1765(20) - Switched Battery
When monitored:Ignition key is turned from off
position to run position and/or ignition key is
turned from crank position to run position.
Set condition:This code is set if the Transmission
Control Module (TCM) senses voltage on any of the
pressure switch inputs prior to the TCM energizing
the relay.
Theory of operation:The transmission control
relay is used to supply power to the solenoid pack
when the transmission is in normal operating
mode. When the relay is off, no power is supplied to
the solenoid pack and the transmission is in a
limp-in mode. The relay output is fed back to the
TCM through pins 16 and 17. It is referred to as the
Trans Relay Output circuit or a switched battery.
Immediately after a controller reset (ignition key
turned to the run position or after cranking engine),
the TCM verifies that the relay contacts are open by
checking for no voltage at the switched battery
terminals. After this is verified, the voltage at the
Solenoid Pack pressure switches is checked. There
should be no voltage on the pressure switches at
this time. The TCM will then activate the relay.
Transmission Effects:The MIL illuminates and
the transmission system defaults to Relay Open
limp-in mode.
Possible causes:
> Short to battery on one or more pressure switch
sense circuits
> TCM connector problems
> TCM
6
GENERAL INFORMATION

Name of code:P1781(21) - OD Pressure Switch
Sense Circuit
When monitored:Whenever the engine is run-
ning.
Set condition:This code is set if the OD pressure
switch is open or closed at the wrong time in a given
gear (see chart below).
Theory of operation:The Transmission system
uses three pressure switches to monitor the fluid
pressure in the L-R, 2-4, and OD clutch circuits.
The pressure switches are continuously monitored
for the correct states in each gear as shown below.
Normal Pressure Switch States
Gear
L-R2-4OD
R OPOPOP
NCLOPOP
1st CL OP OP
2nd OP CL OP
3rd OP OP CL
4th OP CL CL
OP = switch is open
CL = switch is closed
Transmission Effects:Normal operation will be
experienced if no other codes are present. TCM will
ignore the code. Limp-in condition will only occur if
code P1781(21) is present with a code P0705(28).
Possible causes:
> If code P1791(35) is present, ignore code
P1781(21) and perform code P1791 diagnostic
procedures
> OD pressure switch sense circuit open or shorted
to ground between TCM and solenoid pack
> OD pressure switch sense circuit shorted to bat-
tery
> Solenoid pack
> Loose valve body bolts
> Plugged filter - internal transmission or torque
converter failure
> TCM
Name of code:P1782(22) - 2-4 Pressure Switch
Sense Circuit
When monitored:Whenever the engine is run-
ning.
Set condition:This code is set if the 2-4 pressure
switch is open or closed at the wrong time in a given
gear (see chart below).
Theory of operation:The Transmission system
uses three pressure switches to monitor the fluid
pressure in the L-R, 2-4, and OD elements. The
pressure switches are continuously monitored for
the correct states in each gear as shown below.
Normal Pressure Switch States
Gear
L-R2-4OD
R OPOPOP
NCLOPOP
1st CL OP OP
2nd OP CL OP
3rd OP OP CL
4th OP CL CL
OP = switch is open
CL = switch is closed
Transmission Effects: If the 2-4 pressure switch is
identified as closed in P or N, the code will imme-
diately be set and normal operation will be allowed
for that given key start. If the problem is identified
for 3 successive key starts, the transmission will go
into relay open limp-in mode. If the 2-4 pressure
switch is identified as being closed in 1st or 3rd gear
and was not identified as being closed in P or N,
then 2nd gear or 4th gear will be substituted for 1st
or 3rd gear depending on throttle angle and vehicle
speed. A short period of time after the gear substi-
tution, the transmission will return to normal op-
erating mode. If the transmission is shifted back
into 1st or 3rd gear through normal operation, and
the 2-4 pressure switch remains closed, 2nd or 4th
gear will be substituted briefly and then resume
normal operation. If four gear substitutions occur in
a given key start, the transmission will go into relay
open limp-in mode.
If the 2-4 pressure switch is open (indicating no
2-4 clutch pressure) in 2nd or 4th gear, the TCM
sets code P1782(22) and continues with normal
operation. The transmission will only go into relay
open limp-in mode if a code P0705(28) is also
present. If no 2-4 clutch pressure is present a speed
ratio code P0732(52) or P0734(54) will be set and
cause the limp-in condition.
Possible causes:
> If code P1791(35) is present, ignore code
P1782(22) and perform code P1791 diagnostic
procedures
> 2-4 pressure switch sense circuit open or shorted
to ground between TCM and solenoid pack
>
2-4 pressure switch sense circuit shorted to battery
> Solenoid pack
> Transmission overheated - Excessive regulator
valve leakage in valve body causing high line
pressure which results in 2-4 solenoid blow-off in
1st or 3rd gear. May require new valve body if it
happens only when hot.
> Loose valve body bolts
> Plugged filter - internal transmission or torque
converter failure
> TCM
7
GENERAL INFORMATION

Name of code:P1784(24) - L/R Pressure Switch
Sense Circuit
When monitored:Whenever the engine is run-
ning.
Set condition:This code is set if the L-R pressure
switch is either open or closed at the wrong time in
a given gear.
Theory of operation:The Transmission system
uses three pressure switches to monitor the fluid
pressure in the L-R, 2-4, and OD elements. The
pressure switches are continuously monitored for
the correct states in each gear as shown below.
Normal Pressure Switch States
Gear
L-R2-4OD
R OPOPOP
NCLOPOP
1st CL OP OP
2nd OP CL OP
3rd OP OP CL
4th OP CL CL
OP = switch is open
CL = switch is closed
Transmission Effects:If a set condition is identi-
fied, 1st gear and torque converter lock-up (EMCC)
will be inhibited. The vehicle will launch in 2nd
gear and shift normally through the gears without
allowing EMCC. If during the same key start, the
set condition is no longer valid, the transmission
will return to normal operation (1st and EMCC
available). A relay open limp-in will not occur unless
code P1784(24) is accompanied by a code P0705(28).
Possible causes:
> If code P1791(35) is present, ignore code
P1784(24) and perform code P1791(35) diagnos-
tic procedures> L-R pressure switch sense circuit open or shorted
to ground between TCM and solenoid pack
> L-R pressure switch sense circuit shorted to
battery
> Solenoid pack
> Valve body - solenoid switch valve stuck in LU
position. May be accompanied by a code
P1775(37)
> Loose valve body bolts
> Plugged filter - internal transmission or torque
converter failure
> TCM
Name of code:P0705(28) - Check Shifter Signal
When Monitored:Continuously with the key on.
Set Condition:3 occurrences in one key start of an
invalid PRNDL code which lasts for more than 0.1
second.
Theory of Operation:The C1 through C4 (T1, T3,
T41, and T42) sense circuits communicate the shift
lever position to the TCM. Each circuit is termi-
nated at the transmission with a switch. Each
switch can be either open or closed, depending on
the shift lever position. The TCM can decode this
information and determine the shift lever position.
Each shift lever position has a certain combination
of switches which will be open and closed, this is
called a PRNDL code. There are 4 switches, there-
fore: there are many possible combinations of open
and closed switches (codes). However, there are only
9 valid codes (8 for Autostick), one for each gear
position and three recognized between gear codes.
The remainder of the codes shouldnever occur,
these are called invalid codes. The following chart
shows the normal switch states for each shift lever
position.
TRS Park T1 Rev T2 N T2 OD T3 3/AS T3 L
T1 (C4) OP OP OP CL CL CL CL CL OP CL CL
T3 (C3) CL CL OP OP OP OP OP CL CL CL CL
T41 (C1) CL OP OP OP CL OP OP OP OP OP OP
T42 (C2) CL CL CL CL CL CL OP OP OP OP CL
8
GENERAL INFORMATION

responding element is applied. If a switch fails to
close, it is retested, If it fails the second test, the
code is set.
Transmission Effects:The MIL illuminates and
the transmission system defaults to Relay Open
limp-in mode.
Possible causes:
> Pressure switch sense circuit shorted to battery
between TCM and solenoid pack.
> Low line pressure
> Solenoid Pack
Name of code:P1791(35) - Loss Of Prime
When monitored:If the transmission is slipping
in any forward gear and the pressure switches are
not indicating pressure, a loss of prime test is run.
Set condition:If the transmission begins to slip in
any forward gear, and the pressure switch or
switches that should be closed for a given gear are
open, a loss of prime test begins. All available
elements (in 1st gear L-R, 2-4 and OD, in 2nd, 3rd,
and 4th gear 2-4 and OD) are turned on by the
Transmission Control Module (TCM) to see if pump
prime exists. The code is set if none of the pressure
switches respond. The TCM will continue to run the
loss of prime test until pump pressure returns.
Theory of operation:The loss of prime test is
used to prevent transmission defaults which can be
caused by a lack of pump prime.
Transmission Effects:Vehicle will not move or
transmission slips. Normal operation will continue
if pump prime returns.
Possible causes:
> Low transmission fluid level
> PRNDL indicates a valid OD code in the hydrau-
lic reverse position
> Transmission fluid filter clogged or damaged
> Transmission fluid filter improperly installed
(Bolts loose or O-ring missing)
> Oil pump - If a customer has a problem when the
transmission is cold whereby he shifts to reverse,
gets reverse, and then shifts to OD and does not
get OD (gets a neutral condition), and then can
not get reverse or OD for between 3-20 seconds,
replace the oil pump. High side clearance in the
oil pump will set a code 35. The pump will prime
upon start-up, but as the torque converter purges
air (drain down) the air will leak across the inner
rotor into the pump suction port and cause a loss
of prime right after the shift into OD. After 3- 20
seconds, pump prime will return and normal
operation will continue. The pump should be
replaced only after all other possible causes
above have been checked and verified.Name of code:P1790(36) - Fault Immediately
After Shift
When monitored:After a gear ratio error is
stored.
Set condition:This code is set if the associated
gear ratio code is stored within 1.3 seconds after a
shift.
Theory of operation:This code will only be stored
along with a 50 series code. If this code is set, it
indicates the problem is mechanical in nature.
When this code exists, diagnosing the transmission
should be based on the associated gear ratio code
and primarily mechanical causes should be consid-
ered.
Transmission Effects:None
Possible causes:
> Mechanical causes as listed under associated
gear ratio code.
Name of code:P1775(37) - Solenoid Switch Valve
Latched in TCC Position
When monitored:During an attempted shift into
1st gear.
Set condition:This code is set if three unsuccess-
ful attempts are made to get into 1st gear in one
given key start.
Theory of operation:The solenoid switch valve
(SSV) controls the direction of the transmission
fluid when the L-R/TCC solenoid is energized. The
SSV will be in the downshifted position in 1st gear,
thus directing the fluid to the L-R clutch circuit. In
2nd, 3rd, and 4th, it will be in the upshifted position
and directs the fluid into the torque converter
clutch (TCC).
When shifting into 1st gear, a special hydraulic
sequence is performed to ensure SSV movement
into the downshifted position. The L-R pressure
switch is monitored to confirm SSV movement. If
movement is not confirmed (the L-R pressure
switch does not close), 2nd gear is substituted for
1st.
Transmission Effects:Transmission will have no
1st gear (2nd gear will be substituted), and no
EMCC operation.
Possible causes:
> PRNDL indicates a valid OD code in the hydrau-
lic reverse position
> Valve body- - Solenoid valve stuck in TCC posi-
tion
> High idle speed
> Solenoid malfunction - L-R pressure switch will
not close
> L-R Pressure Switch Sense circuit shorted to
battery
10
GENERAL INFORMATION

the L-R pressure switch does not indicate pressure.
A second detection of L-R pressure results in setting
the code.
Transmission Effects:At speeds above 72 Km/h
(45 MPH), EMCC is inhibited. Once speed falls
below 72 Km/h (45 MPH), the transmission will go
into relay open limp-in mode and the MIL will
illuminate.
Possible causes:
> Valve body - Solenoid valve stuck in L-R position
> Intermittent short to ground or open circuit in
L-R Pressure Switch Sense circuit (with code 24
only)
> Solenoid pack (with code P1784(24) only)
> TCM (with code P1784(24) only)
Name of Code:P1793(48) - Torque Reduction
(TRD) Link Communication Error
Note: The MIL may set on some engines (3.3L, 3.8L,
3.5L)
When Monitored:Whenever the engine is run-
ning
Set condition:This code is set when the TCM
sends multiple torque reduction messages to the
PCM and the TCM does not receive a response from
the PCM.
Theory of Operation:During high torque shifts
the TCM will send a message requesting that the
PCM reduce engine power until the shift is com-
pleted. This message is sent from the TCM to the
Powertrain Control Module across the Torque Man-
agement Request Sense Circuit. The PCM will
acknowledge the TCM request by sending a mes-
sage across the PCI bus within a specific amount of
time. The TRD Link communication is also tested
periodically for operation whenever the engine is
running and the vehicle is not moving with zero
degrees throttle.
Transmission Effects:Maximum throttle angle
used by TCM will be 54 degrees. As a result a
customer my complain about loss of performance or
of short shifting when driving aggressively.
Possible Causes:
> Sticky Throttle Position Sensor (TPS)
> Wiring or Connector problems in the Torque
Management Request Sense Circuit
> PCM
> TCM
Name of code:P0736(50) - Gear Ratio Error in
Reverse
P0731(51) - Gear Ratio Error in 1st
P0732(52) - Gear Ratio Error in 2nd
P0733(53) - Gear Ratio Error in 3rd
P0734(54) - Gear Ratio Error in 4th
P0715(56) - Input Speed Sensor Error
P0720(57) - Output Speed Sensor Error
P1794(58) - Speed Sensor Ground Error
When monitored:The transmission gear ratio is
monitored continuously while the transmission is in
gear.
Set condition:This code is set if the gear ratio is
not correct for a period of time.
± Codes 50 through 54 sets if the ratio of the
input RPM (Nt) to the output RPM (No) does
not match the given gear ratio.
± Code 56 sets if there is an excessive change in
input RPM in any gear
± Code 57 sets if there is an excessive change in
output RPM in any gear
± Code 58 sets after a TCM reset in neutral and
Nt/No equals a ratio of input to output of 2.50
A hard code sets within 3 seconds, an intermit-
tent code sets within 15 seconds.
Theory of operation:The transmission system
uses two speed sensors, one to measure input RPM
and one to measure output RPM. These inputs are
essential for proper transmission operation. There-
fore, the integrity of this data is verified through
the following checks:
1. When in gear, if the gear ratio does not compare
to a known gear ratio, the corresponding in-gear
trouble code is set (codes 50 through 54).
2. An excessive change in input or output speeds
indicating signal intermittent will result in
codes 56 and/or 57 being set.
3. After a TCM reset in neutral, observing erratic
output and input speed sensor signals indicates
a loss of the common speed sensors ground. This
sets a code 58.
Transmission Effects:The transmission will not
go into relay open limp-in mode until three gear
ratio error events occur in a given key start. This
allows for intermittent problems to correct them-
selves without opening the relay. However, if a gear
ratio error develops, a code is always set, but if the
condition corrects itself the transmission will con-
tinue without requiring the ignition key to be cycled
on and off. Many different events could occur given
the range of failures possible for codes 50 through
58. The following are a few examples:
± Codes 51, 52, 53, 54, 56, and 57 at speeds
above 72 Km/h (45 MPH) - The appropriate
code is set, EMCC is aborted and current gear
is maintained. If while still traveling above 72
Km/h (45 MPH), the gear ratio becomes valid
again, EMCC will reengage and normal oper-
ation will resume. If the gear ratio becomes
intermittent and recovers three times in a
given key start, the current gear will be main-
tained and EMCC inhibited, then the trans-
mission will go into relay open limp-in mode if
12
GENERAL INFORMATION

throttle is applied below 72 Km/h (45 MPH) or
at 35 Km/h (22 MPH) with closed throttle.
± Codes 51, 52, 53, 54, 56, and 57 (at speeds
between 35 and 72 Km/h (22 and 45 MPH) - If
one of these codes is set between 35 and 72
Km/h (22 and 45 MPH), the current gear will
be maintained until the gear ratio problem
corrects itself. If throttle is applied, the trans
will go to 2nd gear. If this happens and the
gear ratio problem goes away, normal opera-
tion will resume. If three gear ratio problems
are identified in a given key start, the current
gear will be frozen until throttle is applied.
The transmission will then go into relay open
limp-in mode with throttle applied at speeds
between 35 and 72 Km/h (22 and 45 MPH).
± Codes 51, 52, 53, 54, 56, and 57 (at speeds
below 35 Km/h (22 MPH) - If a gear ratio
problem is identified below 35 Km/h (22 MPH),
the transmission will immediately substitute
second gear for the current gear. If the gear
ratio problem goes away, normal operation will
resume. If three gear ratio problems are iden-
tified in a given key start, the transmission
will go into relay open limp-in mode.
Possible causes:
Code P0736(50) - Excludes geartrain failures which
should be obvious upon disassembly
> If code P1791(35) is also set, follow diagnostic
procedure for code P1791(35) first
> Valve body - #1 ball check or LR switch valve
sticking - may also set code P0731(51)
> Speed sensor or associated wiring
± may also set codes P0731(51), P0715(56), or
P0720(57)
> Failed or slipping LR clutch - may also set code
P0731(51)
> LR seal leakage (Intermittent no drive or re-
verse)
> Sticky LR accumulator seals (Intermittent no
drive or reverse)
> Failed reverse clutch (hard code)
± OD/Rev lip seal leakage
± Worn reaction shaft support seal rings
± Snap ring out of position
Code P0731(51) - Excludes geartrain failures which
should be obvious upon disassembly
> If code P1791(35) is also set, follow diagnostic
procedure for code P1791(35) first
> Valve body - #1 ball check or LR switch valve
sticking - may also set code P0736(56) or have no
Reverse
> Speed sensor or associated wiring - may also set
codes P0736(50), P0715(56), or P0720(57)> Failed or intermittent slipping UD clutch - may
also set P0732(52), or P0733(53)
± UD seal leakage (intermittent)
± Worn input clutch hub bushing (hard code at
heavy throttle)
± Sticky UD accumulator seals (intermittent)
± Worn reaction shaft support seal rings (hard
code at heavy throttle)
± Solenoid pack (UD pressure in 4th gear)
> Failed or slipping LR clutch - may also set code
P0736(56) or have no Reverse
± LR seal leakage (Intermittent)
± Sticky LR accumulator seals (Intermittent)
Code P0732(52) - Excludes geartrain failures which
should be obvious upon disassembly
> If code P1791(35) is also set, follow diagnostic
procedure for code P1791(35) first
> Failed or slipping 2-4 clutch - may also set code
P0734(54)
± 2-4 seal leakage (intermittent)
± Sticky accumulator seals (intermittent)
> Failed or intermittent slipping UD clutch - may
also set code P0731(51) and/or P0733(53)
± UD seal leakage (intermittent)
± Worn input clutch hub bushing (hard code at
heavy throttle)
± Sticky UD accumulator seals (intermittent)
± Worn reaction shaft support seal rings (hard
code at heavy throttle)
± Solenoid pack (UD pressure in 4th gear)
Code P0733(53) - Excludes geartrain failures which
should be obvious upon disassembly
> If code P1791(35) is also set, follow diagnostic
procedure for code P1791(35) first
> Failed or slipping OD clutch - may also set code
P0734(54)
± OD and Reverse inner and outer lip seal leak-
age (usually hard code)
± Sticky OD accumulator seals (intermittent)
± Worn reaction shaft support seal rings (hard
code at heavy throttle)
± Broken OD/UD tapered snap ring - (hard code
at heavy throttle)
> Failed or intermittent slipping UD clutch - may
also set code P0731(51) and/or P0732(52)
± UD seal leakage (intermittent)
± Worn input clutch hub bushing (hard code at
heavy throttle)
± Sticky UD accumulator seals (intermittent)
± Worn reaction shaft support seal rings (hard
code at heavy throttle)
13
GENERAL INFORMATION

since there is no power available to control the
transmission solenoids. However if power is re-
stored, the TCM will power-up and normal opera-
tion will be restored. This DTC identifies that
power to the TCM was restored when the gear
selector was in a9Drive9position while the vehicle
was moving at speeds above 32 Km/h (20 MPH). If
a person shifts to Neutral and cycles the ignition
key and quickly shifts to9Drive9while moving
before the TCM comes out of its START ROUTINE,
the DTC can be set. Therefore it is critical that this
DTC diagnosis repair procedure should only be used
if the vehicle is experiencing intermittent 2nd gear
operation and subsequently a return to normal
operation during normal driving.
Transmission Effects:No limp-in condition. The
DTC is for information only when trying to diagno-
sis intermittent 2nd gear operation and subse-
quently a return to normal operation.
Possible Causes:
± No Problem if vehicle is started in9neutral9at
speeds above 32 Km/h (20 MPH) and shifted
quickly to9Drive9before TCM comes out of the
START ROUTINE.
FOR INTERMITTENT 2ND GEAR OPER-
ATION AND THEN A SUBSEQUENT RE-
TURN TO NORMAL OPERATION WITH-
OUT CYCLING THE IGNITION KEY
± Intermittent Direct Battery connection be-
tween TCM (60-way pin 56) and battery.
± Intermittent Fused Ignition Switch Output
between TCM (60-way pin 11) and ignition
switch.
± Intermittent Ground to TCM (60 way pins 53
and 57).
Name of code:P1717(77) - No Communication
with Mechanical Instrument Cluster (MIC)
When monitored:Continuously with key on.
Set condition:If no PCI bus messages are received
from the Mechanical Instrument Cluster (MIC) for
25 seconds.
Theory of operation:The TCM communicates
with the MIC using the PCI bus. It relies on certain
information to function properly. The TCM contin-
uously monitors the PCI bus to check for messages
broadcast from the PCM.
Transmission Effects:Possible improper TCM
AutoStick configuration.
Possible causes:
> Open or shorted PCI bus circuit from MIC
> MIC
> TCM (If other communications codes are stored
in the TCM only)
Name of code:P0600(78) - Serial Communication
Link Malfunction
When monitored:Continuously with key on.
Set condition:If no PCI bus messages are received
by the Transmission Control Module (TCM) for 10
seconds.
Theory of operation:The TCM communicates
with the other modules in the vehicle using the PCI
bus. It relies on certain information to function
properly. The TCM continuously monitors the PCI
bus to check for messages broadcast from the cer-
tain modules.
Transmission Effects:Possible improper TCM
AutoStick configuration and delayed 3-4 shifts. No
EMCC and early 3-4 shifts for a few minutes after
engine is started.
Possible causes:
> Open or shorted PCI bus circuit from BCM
> TCM
Name of code:P1714(79) Low Battery Voltage
When monitored:Continuously with engine run-
ning and Transmission Relay energized.
Set condition:If the voltage sensed at the Trans-
mission Control Relay Output circuit (pins 16 and
17 at TCM) for 15 seconds.
Theory of operation:The Transmission system
requires sufficient battery voltage in order to ener-
gize the transmission solenoids. The TCM continu-
ously monitors the voltage available to the sole-
noids.
Transmission Effects:At speeds above 72 Km/h
(45 MPH) the transmission system will default to
neutral. Below 72 Km/h (45 MPH) the transmission
system will default to relay open limp-in mode.
Park, Reverse, and Neutral are still available.
Possible causes:
> Charging system problem
> Poor/High resistance connection between TCM
and Battery/Alternator
> TCM pin 16 and 17 high resistance or poor
connection
> TCM ground pins 53 and 57 high resistance or
poor connection
> High resistance in Transmission Control Relay
contacts
> TCM
3.3.8 QUICK LEARN
The Quick Learn function customizes adaptive
parameters of the TCM to the transmission charac-
teristics of a vehicle. This gives the customer im-
proved9as received9shift quality compared to the
initial parameters stored in the TCM.
Notes about Quick Learn Features
The nature of the Quick Learn function requires
that certain features must be taken into consider-
ation.
16
GENERAL INFORMATION