torque CHRYSLER VOYAGER 2001 Service Manual

POWERTRAIN CONTROL MODULE C2 - GRAY/GRAY 40 WAYCAV CIRCUIT FUNCTION
41 V37 18VT SPEED CONTROL SWITCH SIGNAL
42 C18 18LB/BR A/C PRESSURE SIGNAL
43 K900 18DB/DG SENSOR GROUND
44 F888 18BR/PK 8 VOLT SUPPLY
45 - -
46 A109 18OR/RD FUSED B(+)
47 - -
48 K40 18BR/LG (2.4L) IDLE AIR CONTROL NO. 3 DRIVER
49 K39 18VT/DG (3.3L/3.8L) IDLE AIR CONTROL NO. 1 DRIVER
49 K60 18VT/LG (2.4L) IDLE AIR CONTROL NO. 2 DRIVER
50 Z131 18BK/DG GROUND
51 K141 18DB/YL OXYGEN SENSOR 1/2 SIGNAL
52 - -
53 - -
54 - -
55 - -
56 V36 18VT/YL SPEED CONTROL VACUUM SOLENOID CONTROL
57 K39 18VT/DG (2.4L) IDLE AIR CONTROL NO. 1 DRIVER
57 K60 18VT/LG (3.3L/3.8L) IDLE AIR CONTROL NO. 2 DRIVER
58 K59 18BR/DG (2.4L) IDLE AIR CONTROL NO. 4 DRIVER
59 D25 18WT/VT PCI BUS
60 - -
61 F855 18PK/YL 5 VOLT SUPPLY
62 B29 18DG/WT BRAKE SWITCH SENSE
63 T10 18DG/LG (3.3L/3.8L) TORQUE MANAGEMENT REQUEST SENSE
64 C13 18LB/OR A/C COMPRESSOR CLUTCH RELAY CONTROL
65 D21 18WT/BR SCI TRANSMIT
66 N7 18DB/OR VEHICLE SPEED SENSOR OUTPUT
67 K51 18BR/WT AUTOMATIC SHUTDOWN RELAY CONTROL
68 K52 18DB/WT EVAPORATIVE EMISSION SOLENOID CONTROL
69 - -
70 K70 18DB/BR EVAPORATIVE EMISSION SOLENOID SENSE
71 - -
72 K107 18VT/WT LEAK DETECTION PUMP SWITCH SENSE
73 K173 18BR/VT RADIATOR FAN RELAY CONTROL
74 K31 18BR FUEL PUMP RELAY CONTROL
75 D20 18WT/LG SCI RECEIVE
76 T41 18YL/DB PARK/NEUTRAL POSITION SWITCH SENSE (TRS T41)
77 K106 18VT/LB LEAK DETECTION PUMP SOLENOID CONTROL
78 K54 18DB/WT (2.4L) TORQUE CONVERTER CLUTCH SOLENOID CONTROL
79 - -
80 V35 18VT/OR SPEED CONTROL VENT SOLENOID CONTROL
C
O
N
N
E
C
T
O
R
P
I
N
O
U
T
S
302
CONNECTOR PINOUTS

TABLE OF CONTENTS - Continued
TRANSMISSION
P0120-THROTTLE POSITION SENSOR SIGNAL CIRCUIT.....................24
P0600-SERIAL COMMUNICATION LINK MALFUNCTION.......................26
P0604-INTERNAL TCM..................................................28
P0605-INTERNAL TCM..................................................29
P0700-INTERNAL TCM..................................................30
P0705-CHECK SHIFTER SIGNAL..........................................31
P0715-INPUT SPEED SENSOR ERROR....................................38
P0720-OUTPUT SPEED SENSOR ERROR..................................42
P0725-ENGINE SPEED SENSOR CIRCUIT (3.3L/3.8L)........................46
P0725-ENGINE SPEED SENSOR CIRCUIT (3.5L)............................48
P0731-GEAR RATIO ERROR IN 1ST.......................................51
P0732-GEAR RATIO ERROR IN 2ND.......................................53
P0733-GEAR RATIO ERROR IN 3RD.......................................55
P0734-GEAR RATIO ERROR IN 4TH.......................................57
P0736-GEAR RATIO ERROR IN REVERSE..................................59
P0740-TORQUE CONVERTER CLUTCH CONTROL CIRCUIT...................61
P0750-LR SOLENOID CIRCUIT............................................63
P0755-2-4 SOLENOID CIRCUIT...........................................66
P0760-OD SOLENOID CIRCUIT...........................................69
P0765-UD SOLENOID CIRCUIT...........................................72
P1714-LOW BATTERY VOLTAGE..........................................75
P1716-BUS COMMUNICATION WITH PCM..................................79
P1717-NO COMMUNICATION WITH THE MIC...............................81
P1738-HIGH TEMPERATURE OPERATION ACTIVATED.......................83
P1739-POWER UP AT SPEED............................................85
P1765-SWITCHED BATTERY.............................................86
P1767-TRANSMISSION RELAY ALWAYS ON................................89
P1768-RELAY OUTPUT ALWAYS OFF......................................92
P1775-SOLENOID SWITCH VALVE LATCHED IN TCC POSITION...............96
P1776-SOLENOID SWITCH VALVE LATCHED IN LR POSITION................100
P1781-OD PRESSURE SWITCH SENSE CIRCUIT...........................104
P1782 - 2-4 PRESSURE SWITCH SENSE CIRCUIT..........................107
P1784-LR PRESSURE SWITCH SENSE CIRCUIT...........................110
P1787-OD HYDRAULIC PRESSURE TEST FAILURE.........................114
P1788-2/4 HYDRAULIC PRESSURE TEST FAILURE.........................118
P1789-2-4/OD HYDRAULIC PRESSURE TEST FAILURE......................122
P1790-FAULT IMMEDIATELY AFTER SHIFT................................123
P1791-LOSS OF PRIME.................................................124
P1792-BATTERY WAS DISCONNECTED...................................127
P1793-TRD LINK COMMUNICATION ERROR...............................130
P1794-SPEED SENSOR GROUND ERROR................................133
P1795-INTERNAL TCM.................................................135
P1796-AUTOSTICK SENSOR CIRCUIT....................................136
P1797-MANUAL SHIFT OVERHEAT.......................................139
P1798-WORN OUT/BURNT TRANSAXLE FLUID.............................140
P1799-CALCULATED OIL TEMP IN USE...................................142
*BRAKE SHIFT INTERLOCK OUTPUT OPEN...............................146
*CHECKING PARK/NEUTRAL SWITCH OPERATION.........................148
*INCORRECT TRANSMISSION FLUID LEVEL...............................150
*NO BACK UP LAMP OPERATION........................................151
*NO SPEEDOMETER OPERATION........................................153
*TRANSMISSION NOISY WITH NO DTC'S PRESENT........................154
ii

TABLE OF CONTENTS - Continued
*TRANSMISSION SHIFTS EARLY WITH NO DTC'S..........................155
*TRANSMISSION SIMULATOR 8333 WILL NOT POWER UP..................156
VERIFICATION TESTS
VERIFICATION TESTS..................................................157
8.0 COMPONENT LOCATIONS..............................................159
8.1POWERTRAIN CONTROL MODULE..................................159
8.2TRANSMISSION CONTROL MODULE................................159
8.3INTELLIGENT POWER MODULE....................................159
8.4PRESSURE PORT LOCATIONS.....................................160
8.5THROTTLE POSITION SENSOR (2.4L)...............................160
8.6AUTOSTICK/OD OFF..............................................160
8.7TRANSMISSION COMPONENT LOCATIONS..........................161
9.0 CONNECTOR PINOUTS................................................163
AUTOSTICK SWITCH - BLACK 2 WAY.....................................163
BODY CONTROL MODULE C2 - BLACK/GREEN 34 WAY.....................163
BRAKE LAMP SWITCH - BLACK 6 WAY...................................164
CRANKSHAFT POSITION SENSOR - BLACK 3 WAY.........................164
DATA LINK CONNECTOR - WHITE 16 WAY................................164
DIAGNOSTIC JUNCTION PORT - BLACK 16 WAY...........................165
INPUT SPEED SENSOR (3.3L/3.8L) - GRAY 2 WAY..........................165
INTELLIGENT POWER MODULE C3 - NATURAL 20 WAY.....................165
INTELLIGENT POWER MODULE C4 - GRAY 10 WAY........................166
INTELLIGENT POWER MODULE C5 - BLACK 4 WAY........................166
INTELLIGENT POWER MODULE C6 - WHITE 10 WAY.......................166
INTELLIGENT POWER MODULE C7 - BLACK 20 WAY.......................167
INTELLIGENT POWER MODULE C9 - BLACK 10 WAY.......................167
LEFT REAR LAMP ASSEMBLY - BLACK 6 WAY.............................167
OUTPUT SPEED SENSOR (3.3L/3.8L) - GRAY 2 WAY........................168
PARK/NEUTRAL POSITION SWITCH (2.4L) - BLACK 3 WAY..................168
FUSES (IPM)..........................................................170
TRANSMISSION SAFETY SHUTDOWN RELAY.............................170
POWERTRAIN CONTROL MODULE C1 - GRAY/BLACK 40 WAY...............171
POWERTRAIN CONTROL MODULE C2 - GRAY/GRAY 40 WAY................172
RIGHT REAR LAMP ASSEMBLY - BLACK 6 WAY............................172
SOLENOID/PRESSURE SWITCH ASSEMBLY (3.3L/3.8L) - BLACK 8 WAY.......173
THROTTLE POSITION SENSOR - GRAY 3 WAY............................173
TORQUE CONVERTER CLUTCH SOLENOID (2.4L) - BLACK 3 WAY...........173
TRANSMISSION CONTROL MODULE (3.3L/3.8L) - BLACK 60 WAY............174
TRANSMISSION RANGE SENSOR (3.3L/3.8L) - GRAY 10 WAY................175
10.0 SCHEMATIC DIAGRAMS................................................177
iii

3.2.2 TRANSMISSION OPERATION AND
SHIFT SCHEDULING AT VARIOUS
OIL TEMPERATURES.
The transmission covered in this manual has
unique shift schedules depending on the tempera-
ture of the transmission oil. The shift schedule is
modified to extend the life of the transmission while
operating under extreme conditions.
The oil temperature is measured with a Temper-
ature Sensor on the 41TE/AE transmission. The
Temperature Sensor is an integral component of the
Transmission Range Sensor (TRS). If the Tempera-
ture Sensor is faulty, (DTC P1799(74)) the trans-
mission will default to a calculated oil temperature.
Oil temperature will then be calculated through a
complex heat transfer equation which uses engine
coolant temperature, battery/ambient temperature,
and engine off time from the Body Control Module
(BCM). These inputs are received from the PCI bus
periodically and used to initialize the oil tempera-
ture at start up. Once the engine is started, the
TCM updates the transmission oil temperature
based on torque converter slip speed, vehicle speed,
gear, and engine coolant temperature to determine
an estimated oil temperature during vehicle opera-
tion. Vehicles using a calculated oil temperature
track oil temperature reasonably accurate during
normal operation. However, if a transmission is
overfilled, a transmission oil cooler becomes re-
stricted, or if a customer drives aggressively in low
gear, the calculated oil temperature will be inaccu-
rate. Consequently the shift schedule selected may
be inappropriate for the current conditions. The key
highlights of the various shift schedules are as
follows:
Extreme Cold:Oil temperature at start up below
-26.6C (-16ÉF)
> Goes to a Cold schedule above -24C (-12ÉF) oil
temperature
> Park, Reverse, Neutral and 2nd gear only (pre-
vents shifting which may fail a clutch with fre-
quent shifts)
Cold:Oil temperature at start up above -24C
(-12ÉF) and below 2.2C (36ÉF)
> Goes to a Warm schedule above 4.4C (40ÉF) oil
temperature
> Delayed 2-3 upshift approximately 35-50 Km/h
(22-31 MPH)
> Delayed 3-4 upshift 72-85 Km/h (45-53 MPH)
> Early 4-3 coastdown shift approximately 48
Km/h (30 MPH)
> Early 3-2 coastdown shift approximately 27
Km/h (17 MPH)> High speed 4-2, 3-2, 2-1 kickdown shifts are
prevented
> No EMCC
Warm:Oil temperature at start up above 2.2C
(36ÉF) and below 27C (80ÉF)
> Goes to a Hot schedule above 27C (80ÉF) oil
temperature
> Normal operation (upshifts, kickdowns, and
coastdowns)
> No EMCC
Hot:Oil temperature at start up above 27C (80ÉF)
> Goes to a Overheat schedule above 115C (240ÉF)
oil temperature
> Normal operation (upshifts, kickdowns, and
coastdowns)
> Full EMCC, No PEMCC except to engage
FEMCC
(Except at closed throttle at speeds above 113-133
Km/h (70 - 83 MPH)
Overheat:Oil temperature above 115C (240ÉF) or
engine coolant temperature above 118C (244ÉF)
> Goes to a Hot below 110C (230ÉF) oil temperature
or a Super Overheat above 115C (240ÉF) oil
temperature
> Delayed 2-3 upshift 40-51 Km/h (25-32 MPH)
> Delayed 3-4 upshift 66-77 Km/h (41-48 MPH)
> 3rd gear FEMCC from 48-77 Km/h (30-48 MPH)
> 3rd gear PEMCC from 43-50 Km/h (27-31 MPH)
Super Overheat:Oil temperature above 127C
(260ÉF)
> Goes back to a Overheat below 115C (240ÉF) oil
temperature
> All a Overheat shift schedules features apply
> 2nd gear PEMCC above 35 Km/h (22 MPH)
> Above 35 Km/h (22 MPH) the torque converter
will not unlock unless the throttle is closed (i.e. at
80 Km/h (50 MPH) a 4th FEMCC to 3rd FEMCC
shift will be made during a part throttle kick-
down or a 4th FEMCC to 2nd PEMCC shift will
be made at wide open throttle) or if a wide open
throttle 2nd PEMCC to 1 kickdown is made.
Causes for operation in the wrong tempera-
ture shift schedule:
Extreme Cold or Cold shift schedule at start up:
> Temperature Sensor circuit.
Overheat or Super Overheat shift schedule after
extended operation:
> Operation in city traffic or stop and go traffic
> Engine idle speed too high
> Aggressive driving in low gear
2
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

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

Name of code:P0740(38) - Torque Converter
Clutch Control Circuit
When monitored:During Electronically Modu-
lated Converter Clutch (EMCC)
Set condition:
a) The transmission must be in EMCC, with the
input speed greater than 1750 RPM. The TCC/L-R
solenoid must achieve it's maximum duty cycle and
still not be able to pull the engine speed within 60
RPM of input speed.
b) If the transmission is in FEMCC and the engine
can slip the TCC by more than 100 RPM (Engine
speed - Input speed) for 10 seconds.
The code will be set if one of these event happens
three times at a throttle angle less than 30 degrees.
Theory of operation:When in 2nd, 3rd, or 4th
gear, the torque converter clutch (TCC) can be
locked when certain conditions are met. The TCC
piston is electronically modulated by increasing the
duty cycle of the L-R/TCC solenoid until the torque
converter slip difference (difference between engine
and turbine speed) is within 60 RPM. Then the
L-R/TCC solenoid is fully energized (FEMCC / 100%
duty cycle). Torque converter slip is monitored in
FEMCC to ensure adequate clutch capacity.
Transmission Effects:EMCC will still be avail-
able after code is set. MIL will illuminate after 5
minutes of accumulated slip in FEMCC. The trans-
mission will attempt normal operation (no limp-in)
even after the MIL is illuminated.
Possible causes:
> Worn pump bushing and/or failed torque con-
verter - both should be replaced during a rebuild
with code P0740(38) present
> Solenoid pack.
Name of code:P0750(41) - L-R Solenoid Circuit
P0755(42) - 2-4 Solenoid Circuit
P0760(43) - OD Solenoid Circuit
P0765(44) - UD Solenoid Circuit
When monitored:Ignition key is turned from off
position to run position and/or ignition key is
turned from crank position to run position, then
every 10 seconds thereafter, or when a speed ratio
or pressure switch error DTC is detected.
Set condition:All four solenoids are tested for
continuity continuously immediately upon start up
and during vehicle operation. For solenoids that are
currently energized, power is momentarily inter-
rupted, then reenergized. For solenoids that are not
currently energized, the solenoid is momentarily
energized, then deenergized. Under both situations,
if an inductive spike is not sensed by the Transmis-
sion Control Module (TCM) during the continuity
check, it is retested twice. If it fails the test the
third time, the appropriate code is set.
Gear UD OD Rev 2-4 L-R
Park X
Reverse X X
Neutral X
1st X X
2nd X X
3rd X X
4th X X
Theory of operation:Four solenoids are used to
control the friction elements (clutches). The conti-
nuity of the solenoids circuits are periodically
tested. Each solenoid is turned on or off depending
on it's current state. An inductive spike should be
detected by the TCM during this test. If no spike is
detected, the circuit is tested again to verify the
failure. In addition to the periodic testing, the
solenoid circuits are tested if a speed ratio or
pressure switch error occurs. In this case, one
failure will result in the appropriate code being set.
Transmission Effects:The MIL will illuminate
and the transmission goes into neutral if code is set
above 35 Km/h (22 MPH), limp-in mode when
vehicle speed is below 35 Km/h (22 MPH).
Possible causes:
> Open or shorted solenoid circuit(s) between TCM
and solenoid pack.
> Open ground circuit.
> TCM connector problems.
> Solenoid pack connector problem.
> Solenoid Pack.
> TCM
Name of code:P1776(47) - Solenoid Switch Valve
(SSV) Latched in L-R Position
When monitored:Continuously when doing par-
tial or full EMCC (PEMCC or FEMCC)
Set condition:If the transmission senses the L-R
pressure switch closing while performing PEMCC
or FEMCC. This code will be set after two unsuc-
cessful attempts to perform PEMCC or FEMCC.
Theory of operation:The solenoid switch valve
(SSV) controls the direction of the transmission
fluid when the L-R/TCC solenoid is energized. SSV
will be in the downshifted position in 1st gear, thus
directing the fluid to the L-R clutch circuits. In 2nd,
3rd, and 4th, the SSV will be in the upshifted
position and directs the fluid into the torque con-
verter clutch (TCC). When doing PEMCC or
FEMCC, the L-R pressure switch should indicate no
pressure if the SSV is in the TCC position. If the
L-R pressure switch indicates pressure while in
PEMCC or FEMCC, EMCC operation is aborted
and inhibited to avoid inadvertent application of
the L-R clutch. Partial EMCC will be attempted if
11
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