engine cooling CHRYSLER VOYAGER 2001 Service Manual

CAUTION:
When removing hoses from outlet nipples, do not
use excessive force. Outlet nipples may become
damaged and leak engine coolant.
(4) Compress insert in rear heater hose quick con-
nection and pull downward on hose. (Fig. 12)
(5) Remove (3) straps securing underbody lines.
(Fig. 9)
(6) Separate and remove rear heater lines from
vehicle.
INSTALLATION
There are several heater core plumbing configura-
tions used on this model, depending upon the engine
size and other optional equipment. One plumbing
configuration is used for all 2.4L engines (Fig. 21),
while the 3.3L and 3.8L engines have unique heater
return plumbing on the engine for models with or
without an optional engine oil cooler (Fig. 24) or (Fig.
25). There are also unique plumbing configurations
at the heater core for models with or without the
optional rear heater and air conditioner (Fig. 22) or
(Fig. 23). All models use a combination of formed
steel tubing and rubber hoses. In most cases, the
rubber hose is secured to the steel tubing with a
spring tension clamp.
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING FRONT - WARNING - HEATER PLUMB-
ING).
(1) Using spring tension clamp pliers, compress
and slide the clamps that secure each end of the
heater hose toward the center of the hose being
installed. Release the clamp when it is near the cen-
ter of the hose.
(2) Grasp one end of the heater hose being
installed firmly and carefully twist the hose back and
forth while pushing it over from the barbed end of
the nipple. Repeat this procedure at the opposite end
of the hose being installed.
(3) Using spring tension clamp pliers, compress
and slide the clamps that secure each end of the
heater hose over the tube or nipple. Release the
clamp when it is over the tube or nipple.
(4) Refill the engine cooling system. (Refer to 7 -
COOLING - STANDARD PROCEDURE - COOLING
SYSTEM REFILL).
SUCTION LINE
REMOVAL
The front air conditioner suction line includes the
low side service port on a section of tubing located
near the compressor. On models equipped with the
optional rear air conditioner, the front air conditioner
suction line also includes a suction line hose and
tube extension that connects the front suction line to
the suction line for the rear air conditioner.
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - WARNING - A/C PLUMBING)
and (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - CAUTION - A/C PLUMBING).
(1) Recover the refrigerant from the refrigerant
system. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - FRONT/REFRIGERANT -
STANDARD PROCEDURE - REFRIGERANT
RECOVERY).
(2) Disconnect and isolate the battery negative
cable.
(3) Remove the air cleaner top cover and snorkel
from the air cleaner housing located on the right side
of the engine compartment.
(4) Disconnect the drain tube from the wiper mod-
ule drain on the right side of the engine compart-
ment.
(5) Remove the nut that secures the suction line
fitting to the top of the compressor.
(6) Disconnect the suction line fitting from the
compressor suction port.
(7) Remove the seal from the suction line fitting
and discard.
(8) Install plugs in, or tape over the opened suc-
tion line fitting and the compressor suction port.
(9) Disengage the retainer that secures the suction
line routing clip to the filter-drier mounting bracket
on the side of the right front strut tower in the
engine compartment (Fig. 7).
(10) Remove the nut that secures the suction line
and liquid line fittings to the expansion valve.
(11) Disconnect the suction line and liquid line fit-
tings from the expansion valve.
(12) Remove the seals from the suction line and
liquid line fittings and discard.
(13) Install plugs in, or tape over the opened suc-
tion line and liquid line fittings and both expansion
valve ports.
(14) If the vehicle is equipped with the optional
rear air conditioner, go to Step 15. If the vehicle does
RSPLUMBING - REAR24 - 103
HEATER HOSE (Continued)

(10) Install and tighten the nut that secures the
suction line fitting to the compressor. Tighten the nut
to 23 N´m (17 ft. lbs.).
(11) Reconnect the drain tube to the wiper module
drain on the right side of the engine compartment.
(12) Reinstall the air cleaner top cover and snorkel
onto the air cleaner housing located on the right side
of the engine compartment.
(13) Reconnect the battery negative cable.
(14) If the vehicle is equipped with the optional
rear air conditioner, go to Step 15. If the vehicle does
not have the optional rear air conditioner, go to Step
21.
(15) Raise and support the vehicle.
(16) Remove the tape or plugs from the suction
line extension fitting and the underbody suction line
fitting (Fig. 35).
(17) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the underbody suction
line fitting.
(18) Reconnect the suction line extension fitting to
the underbody suction line fitting. Tighten the fit-
tings to 23 N´m (17 ft. lbs.).
(19) Install a new tie strap just forward of the con-
nections between the underbody plumbing and the
engine compartment plumbing for the rear heater
and air conditioner.
(20) Lower the vehicle.
(21) Evacuate the refrigerant system. (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM EVACUATE).
(22) Charge the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM CHARGE).UNDERBODY LINES
DESCRIPTION
The rear heater-A/C unit plumbing is used only on
models with the optional rear heater-A/C unit. The
formed metal rear heater-A/C unit suction line, liquid
line, and heater lines are available for separate ser-
vice replacement. The molded and straight heater
hoses used on the rear heater-A/C unit can be ser-
viced in the vehicle. Refer to Group 7 - Cooling Sys-
tem for the heater hose service procedures.
OPERATION
The rear heater and A/C lines are all serviced as
individual pieces. When disconnecting any line or
block ensure that the area around it is clean of any
contaminations that can get in to the system (Fig. 9),
(Fig. 10), (Fig. 12), (Fig. 11) and (Fig. 13).
Any kinks or sharp bends in the rear heater-A/C
unit plumbing will reduce the capacity of the entire
heating and air conditioning system. Kinks and
sharp bends reduce the system flow. High pressures
are produced in the refrigerant system when the air
conditioning compressor is operating. High tempera-
ture coolant is present in the heater plumbing when
the engine is operating. Extreme care must be exer-
cised to make sure that each of the plumbing connec-
tions is pressure-tight and leak free.
Fig. 9 Rear Heater and A/C Lines
1 - HEATER CONNECTION
2 - REAR A/C LINE BLOCK CONNECTION
RSPLUMBING - REAR24 - 105
SUCTION LINE (Continued)

INSTALLATION
(1) Install both flexible coolant lines to the heater
unit and install clamps.
(2) Install flexible coolant lines to the coolant pipes
and install clamps.
(3) Install heater unit into vehicle(Refer to 24 -
HEATING & AIR CONDITIONING/CABIN HEAT-
ER/HEATER UNIT - INSTALLATION).
(4) Lower vehicle.
(5) Refill cooling system(Refer to 7 - COOLING -
STANDARD PROCEDURE).
(6) Verify operation of heater unit.
HEATER PIPES - DIESEL
SUPPLEMENTAL HEATER
REMOVAL
CAUTION: Allow cooling system to cool completely
before removing radiator cap or draining cooling
system. Injury could result is system is opened
while system coolant is hot and under pressure.
NOTE: Steel heater lines from engine compartment
to heater unit are part of an assembly that includes
the air intake pipe. If the heater lines or air intake
pipe require removal or replacement the entire
assembly must be removed or replaced.
(1) Open hood.
(2) Drain the cooling system(Refer to 7 - COOL-
ING - STANDARD PROCEDURE).
(3) Remove clamps from both the EGR cooler and
the lower heater port. Separate hoses from the mat-
ing plumbing port. (Fig. 1).
(4) Remove retaining nut from heater line under
hood bracket.(5) Elevate vehicle on a lift.
NOTE: When supporting vehicle care should be
taken not to damage the heater exhaust tube.
(6) Remove clamps from heater lines to the rubber
connection nearest the tubes. Separate the hoses
from the tube assembly leaving the rubber hose
attached to the supplemental heater.
(7) Remove heater unit intake pipe from heater-
(Refer to 24 - HEATING & AIR CONDITIONING/
CABIN HEATER/INLET HOSE - REMOVAL) (Fig.
2).
(8) Remove heater pipe assembly retaining screws
and remove assembly from vehicle.
INSTALLATION
(1) With vehicle on a lift position the heater pipe
assembly and install the retaining screws.
(2) Install the heater unit intake pipe to the
heater unit(Refer to 24 - HEATING & AIR CONDI-
TIONING/CABIN HEATER/INLET HOSE - INSTAL-
LATION).
(3) Connect heater hoses to the heater unit and
tighten the clamps.
(4) Install heater unit intake pipe to heater uni-
t(Refer to 24 - HEATING & AIR CONDITIONING/
CABIN HEATER/INLET HOSE - INSTALLATION).
(5) Lower vehicle on lift.
(6) Install retaining nut to heater line under hood
bracket and tighten.
(7) Connect heater lines to heater hoses at heater
core and EGR port. Position spring clamps onto the
installed hoses.
(8) Refill cooling system(Refer to 7 - COOLING -
STANDARD PROCEDURE).
(9) Close hood.
24a - 2 HEATING & AIR CONDITIONINGRG
HEATER HOSES - DIESEL SUPPLEMENTAL HEATER (Continued)

OPERATION
The engines use Exhaust Gas Recirculation (EGR)
systems. The EGR system reduces oxides of nitrogen
(NOx) in engine exhaust and helps prevent detona-
tion (engine knock). Under normal operating condi-tions, engine cylinder temperature can reach more
than 3000ÉF. Formation of NOx increases proportion-
ally with combustion temperature. To reduce the
emission of these oxides, the cylinder temperature
must be lowered. The system allows a predetermined
amount of hot exhaust gas to recirculate and dilute
the incoming air/fuel mixture. The diluted air/fuel
mixture reduces peak flame temperature during com-
bustion.
REMOVAL
(1) Remove engine cover (Refer to 9 - ENGINE -
REMOVAL).
(2) Remove front wiper unit (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS/WIPER MODULE -
REMOVAL).
(3) Disconnect EGR valve vacuum line.
(4) Remove EGR cooler to EGR valve retaining
bolts (Fig. 1).
(5) Remove EGR valve retaining nuts (Fig. 1) and
EGR valve.
INSTALLATION
(1) Clean gasket mating surfaces.
(2) Install EGR valve (Fig. 1). Torque nuts to
32.4N´m.
(3) Connect EGR cooler to EGR valve (Fig. 1).
Torque bolts to 32.4N´m
(4) Install front wiper unit (Refer to 8 - ELECTRI-
CAL/WIPERS/WASHERS/WIPER MODULE -
INSTALLATION).
(5) Install engine cover (Refer to 9 - ENGINE -
INSTALLATION) .
VALVE COOLER
DESCRIPTION
The EGR valve on this engine uses a cooler to cool
the exhaust gases before the returned to the intake
manifold (Fig. 2). The EGR cooler attaches to the
EGR valve and is cooled with engine coolant.
REMOVAL
(1) Remove engine cover (Refer to 9 - ENGINE -
REMOVAL).
(2) Partially drain cooling system (Refer to 7 -
COOLING/ENGINE/COOLANT - STANDARD PRO-
CEDURE).
(3) Remove front wiper unit (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS/WIPER MODULE -
REMOVAL) .
(4) Disconnect coolant supply and return lines at
EGR cooler (Fig. 2).
(5) Remove EGR cooler to exhaust manifold retain-
ing bolt (Fig. 2).
Fig. 1 EGR COMPONENTS
1 - HOSE CLAMP
2 - COOLANT HOSE
3 - HOSE CLAMP
4 - EGR VALVE RETAINING NUT
5 - E G R VA LV E
6 - COOLANT HOSE
7 - EGR VALVE GASKET
8 - EGR VALVE RETAINING STUDS
9 - EGR COOLER RETAINING BOLT
10 - HOSE CLAMP
11 - HOSE CLAMP
12 - EGR COOLER
13 - EGR COOLER TO EGR VALVE RETAINING BOLT
14 - TURBOCHARGER BRACKET
15 - TURBOCHARGER BRACKET RETAINING BOLT
16 - TURBOCHARGER DOWNPIPE
17 - TURBOCHARGER DOWNPIPE RETAINING NUT
18 - DOWNPIPE GASKET
19 - DOWNPIPE STUD
25a - 4 EXHAUST GAS RECIRCULATIONRG
VALVE (Continued)

(6) Remove EGR cooler to EGR valve retaining
bolts (Fig. 2) and remove cooler.
INSTALLATION
(1) Clean gasket sealing surfaces.
(2) Connect EGR valve cooler and new gasket to
EGR valve (Fig. 2). Torque bolts to 32.4N´m.
(3) Install EGR valve cooler to exhaust manifold
attaching bolt (Fig. 2). Torque bolt to 32.4N´m.
(4) Connect EGR cooler coolant supply and return
hoses to cooler (Fig. 2).
(5) Install front wiper unit (Refer to 8 - ELECTRI-
CAL/WIPERS/WASHERS/WIPER MODULE -
INSTALLATION).
(6) Refill cooling system (Refer to 7 - COOLING/
ENGINE/COOLANT - STANDARD PROCEDURE).
(7) Install engine cover (Refer to 9 - ENGINE -
INSTALLATION) .
Fig. 2 EGR COMPONENTS
1 - HOSE CLAMP
2 - COOLANT HOSE
3 - HOSE CLAMP
4 - EGR VALVE RETAINING NUT
5 - E G R VA LV E
6 - COOLANT HOSE
7 - EGR VALVE GASKET
8 - EGR VALVE RETAINING STUDS
9 - EGR COOLER RETAINING BOLT
10 - HOSE CLAMP
11 - HOSE CLAMP
12 - EGR COOLER
13 - EGR COOLER TO EGR VALVE RETAINING BOLT
14 - TURBOCHARGER BRACKET
15 - TURBOCHARGER BRACKET RETAINING BOLT
16 - TURBOCHARGER DOWNPIPE
17 - TURBOCHARGER DOWNPIPE RETAINING NUT
18 - DOWNPIPE GASKET
19 - DOWNPIPE STUD
RGEXHAUST GAS RECIRCULATION25a-5
VALVE COOLER (Continued)

1.0 INTRODUCTION
The procedures contained in this manual include
specifications, instructions, and graphics needed to
diagnose the PCM Powertrain System. The diag-
nostics in this manual are based on the failure
condition or symptom being present at time of
diagnosis.
Please follow the recommendations below when
choosing your diagnostic path.
1. First make sure the DRBIIItis communicating
with the appropriate modules; ie., if the DRBIIIt
displays a No Response condition, you must
diagnose this first before proceeding.
2. Read DTC's (diagnostic trouble codes) with the
DRBIIIt.
3. If no DTC's are present, identify the customer
complaint.
4. Once the DTC or customer complaint is identi-
fied, locate the matching test in the Table of
Contents and begin to diagnose the symptom.
All component location views are in Section 8.0.
All connector pinouts are in Section 9.0. All system
schematics are in Section 10.0.
An * placed before the symptom description indi-
cates a customer complaint.
When repairs are required, refer to the appropri-
ate service information for the proper removal and
repair procedure.
Diagnostic procedures change every year. New
diagnostic systems may be added; carryover sys-
tems may be enhanced. READ THIS DIAGNOSTIC
INFORMATION BEFORE TRYING TO DIAG-
NOSE A VEHICLE CODE. It is recommended that
you review the entire diagnostic information to
become familiar with all new and changed diagnos-
tic procedures.
If you have any comments or recommendations
after reviewing the diagnostic information, 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 the
following 2001 Town and Country; Caravan/Grand
Caravan; and Voyager/Grand Voyager vehicles
equipped with the 2.4L and the 3.3L/3.8L engines.
1.2 SIX-STEP TROUBLESHOOTING
PROCEDURE
Diagnosis of the powertrain control module
(PCM) is done in six basic steps:
²verification of complaint
²verification of any related symptoms
²symptom analysis
²problem isolation
²repair of isolated problem
²verification of proper operation
2.0 IDENTIFICATION OF
SYSTEM
The Powertrain Control Module (PCM) monitors
and controls:
²Fuel System
²Idle Air Control System
²Ignition System
²Charging System
²Speed Control System
²Cooling system
3.0 SYSTEM DESCRIPTION AND
FUNCTIONAL OPERATION
3.1 GENERAL DESCRIPTION
These Sequential Fuel Injection (SFI) engine sys-
tems have the latest in technical advances. The
on-board Euro Stage III OBD diagnostics incorpo-
rated with the Powertrain Control Module (PCM)
are intended to assist the field technician in repair-
ing vehicle problems by the quickest means.
3.2 FUNCTIONAL OPERATION
3.2.1 FUEL CONTROL
The PCM controls the air/fuel ratio of the engine
by varying fuel injector on time. Mass air flow is
calculated using the speed density method using
enigne speed, manifold absolute pressure, and air
temperature change.
Different fuel calculation strategies are used de-
pending on the operational state of the engine.
During crank mode, a prime shot fuel pulse is
delivered followed by fuel pulses determined by a
crank time strategy. Cold engine operation is deter-
mined via an open loop strategy until the O2
sensors have reached operating temperature. At
this point, the strategy enters a closed loop mode
where fuel requirements are based upon the state of
the O2 sensors, engine speed, MAP, throttle posi-
tion, air temperature, battery voltage, and coolant
temperature.
1
GENERAL INFORMATION

Symptom:
P0125-CLOSED LOOP TEMP NOT REACHED
When Monitored and Set Condition:
P0125-CLOSED LOOP TEMP NOT REACHED
When Monitored: With battery voltage greater than 10.4 volts, after engine is started.
Set Condition: The engine temperature does not go above 60ÉF (15ÉC). F Time depen-
dants on start-up coolant temperature and ambient temperature. (i.e. 2 minutes for a start
temp of 10ÉC (50ÉF) or up to 10 mintues for a vehicle with a start-up temp of -28ÉC (20ÉF).
Two trips are required to set this DTC.
POSSIBLE CAUSES
LOW COOLANT LEVEL
THERMOSTAT OPERATION
ENGINE COOLANT TEMPERATURE SENSOR
TEST ACTION APPLICABILITY
1NOTE: If a ECT DTC set along with this code, diagnose the ECT DTC first.
NOTE: Inspect the ECT terminals and related PCM terminals. Ensure the
terminals are free from corrosion and damage.
NOTE: The best way to diagnose this DTC is to allow the vehicle to sit
overnight outside in order to have a totally cold soaked engine.
Note: Extremely cold outside ambient temperatures may have caused this
DTC to set.
WARNING: Never open the cooling system when the engine is hot. The
system is under pressure. Extreme burns or scalding may result. Allow the
engine to cool before opening the cooling system.
Check the coolant system to make sure that the coolant is in good condition and at
the proper level.
Is the coolant level and condition OK?All
Ye s®Go To 2
No®Inspect the vehicle for a coolant leak and add the necessary
amount of coolant.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
71
DRIVEABILITY - GAS

Symptom:
P1281-ENGINE IS COLD TOO LONG
When Monitored and Set Condition:
P1281-ENGINE IS COLD TOO LONG
When Monitored: The ignition key on, engine running.
Set Condition: The engine does not warm to 71ÉC (160ÉF) while driving (throttle off idle)
greater than 20 MPH for 20 minutes after start.
POSSIBLE CAUSES
COOLING SYSTEM PROBLEM
TEST ACTION APPLICABILITY
1NOTE: The best way to diagnose this DTC is to allow the vehicle to remain
outside overnight in order to have a completely cold soaked engine.
NOTE: Extremely cold outside ambient temperatures may cause this DTC to
set.
Verify that the coolant level is correct. If not, repair as necessary
NOTE: Ensure the ECT Sensor is operating correctly.
With the DRBIIIt, monitor the Engine Coolant Temperature value during the warm
up cycle. Make sure the transition of the temperature change is smooth.
Did the engine temperature reach a minimum of 71ÉC (160ÉF)?All
Ye s®Test Complete.
No®Refer to the Service Information for cooling system performance
diagnosis. The most probable cause is a Thermostat problem.
Also, refer to any related TSBs.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
180
DRIVEABILITY - GAS

> Trailer towing in OD gear position (use 3 position
(or A/S 3rd) if frequent shifting occurs)
> Cooling system failure causing engine to operate
over 110C (230ÉF)
> Engine coolant temperature stays low too long -
If engine coolant temperature drops below 65C
(150ÉF), the transmission will disengage EMCC.
Extended operation with the EMCC disengaged
will cause the transmission to overheat.
> A brake switch issue will cause the EMCC to
disengage. Extended operation with the EMCC
disengaged will cause the transmission to over-
heat.
> Transmission fluid overfilled
> Transmission cooler or cooler lines restricted
> Transmission Temperature Sensor circuit
3.3 DIAGNOSTIC TROUBLE CODES
Diagnostic trouble codes (DTC's) are codes stored
by the Transmission Control Module (TCM) that
help us diagnose Transmission problems. They are
viewed using the DRBIIItscan tool.
Always begin by performing a visual inspection of
the wiring, connectors, cooler lines and the trans-
mission. Any obvious wiring problems or leaks
should be repaired prior to performing any diagnos-
tic test procedures. Some engine driveability prob-
lems can be misinterpreted as a transmission prob-
lem. Ensure that the engine is running properly
and that no PCM DTC's are present that could
cause a transmission complaint.
If there is a communication bus problem, trouble
codes will not be accessible until the problem is
fixed. The DRBIIItwill display an appropriate
message. The following is a possible list of causes
for a bus problem:
± open or short to ground/battery in PCI bus
circuit (pin 43).
± internal failure of any module or component on
the bus
Each diagnostic trouble code is diagnosed by
following a specific testing sequence. The diagnostic
test procedures contain step-by-step instructions
for determining the cause of a transmission diag-
nostic trouble code. Possible sources of the code are
checked and eliminated one by one. It is not neces-
sary to perform all of the tests in this book to
diagnose an individual code. These tests are based
on the problem being present at the time that the
test is run.All testing should be done with a
fully charged battery.
If the TCM records a DTC that will adversely
affect vehicle emissions, it will request (via the
communication bus) that the PCM illuminate the
Malfunction Indicator Lamp (MIL). Although theseDTC's will be stored in the TCM immediately as a 1
trip failure, it may take up to five minutes of
accumulated trouble confirmation set the DTC and
illuminate the MIL. Three consecutive successful
OBDII (EURO STAGE III OBD) trips or clearing
the DTC's with a diagnostic tool (DRBIIItor equiv-
alent) is required to extinguish the MIL. When the
TCM requests that the PCM illuminate the MIL,
the PCM sets a DTC P0700(89) to alert the techni-
cian that there are DTC's in the TCM. This must
also be erased in the PCM in order to extinguish the
MIL.
3.3.1 HARD CODE
Any Diagnostic Trouble Code (DTC) that is set
whenever the system or component is monitored is
a HARD code. This means that the problem is there
every time the TCM checks that system or compo-
nent. Some codes will set immediately at start up
and others will require a road test under specific
conditions. It must be determined if a code is
repeatable (Hard) or intermittent before attempt-
ing diagnosis.
3.3.2 ONE TRIP FAILURES
A One Trip Failure, when read from the TCM, is
a hard OBDII (EURO STAGE III OBD) code that
has not matured for the full 5 minutes. This applies
to codes that will only set after 5 minutes of
substituted gear operation.
3.3.3 INTERMITTENT CODE
A diagnostic trouble code that is not there every
time the TCM checks the circuit or function is an a
intermittent code. Some intermittent codes, such as
codes P1792(12), P1767(14), P1768(15), P0725(18),
P1716(19), P1781(21), P1782(22), P1724(24),
P0705(28), P0120(29), P0750(41), P0755(42),
P0760(43), P0765(44), P1793(48), P0715(56),
P0720(57), P1794(58), P1796(70), P1799(74),
P1739(76), P1717(77), and P0600(78) are caused by
wiring or connector problems. However intermit-
tent codes 50 - 54 are usually caused by intermit-
tent hydraulic seal leakage in the clutch and/or
accumulator circuits. Problems that come and go
like this are the most difficult to diagnose, they
must be looked for under the specific conditions
that cause them.
3.3.4 STARTS SINCE SET COUNTER
For the most recent code (Code 1), the Starts
Since Set counter counts the number of times the
vehicle has started since it was last set. The counter
will count up to 255 starts. Note that this code only
applies to the last code set.
When there are no diagnostic trouble codes stored
in memory, the DRBIIItwill display ``NO DTC'S
3
GENERAL INFORMATION

± Solenoid pack (UD pressure in 4th gear)
Code P0734(54) - 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
P0733(53)
± 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 slipping 2-4 clutch - may also set code
P0732(52)
± 2-4 seal leakage (intermittent)
± Sticky accumulator seals (intermittent)
Codes P0715(56) and P0720(57)
> Failed input or output speed sensor (intermittent
or hard code)
> Shorted or open wiring between TCM and speed
sensor(s) (intermittent)
> Connector problems at 60 TCM connector and/or
speed sensor connector
Code P1794(58)
> Open or shorted speed sensor ground (speed
sensor ground is different from chassis ground)
> Open or shorted Temperature Sensor wiring to
TRS
> TRS - Will also set code P1799(74)
> TCM
Name of code:P1796(70) - Autostick Sensor Cir-
cuit (If equipped)
Note: RS is a MUXED Autostick system
When monitored:Whenever the engine is run-
ning.
Set condition:
1) The transmission shift lever is not in AutoStick
and either the upshift or downshift switch is closed.
2) Upshift and downshift switches closed at the
same time.
Theory of operation:In the AutoStick Mode
(manual shift mode), upshifts and downshifts are
actuated manually. Shift requests are detected by
monitoring the MUXED upshift and downshift
switches. The Transmission Control Module (TCM)
monitors the above set conditions. A set condition
will be tolerated for up to 15 seconds before setting
a code.Transmission Effects:The OD position shift
schedule is substituted while operating in the au-
tostick gear selector position. No limp-in mode
occurs.
Possible causes:
> Wiring or connector problems
> AutoStick switch failure
> TCM
Name of code:P1797(71)- Manual Shift Overheat
When monitored:Whenever the engine is run-
ning.
Set condition:1) If the engine temperature ex-
ceeds 124C (255 ÉF) while operating in AutoStick
mode.
2) If the transmission temperature exceeds 135C
(275 ÉF) while in AutoStick mode
Theory of operation:Transmission and engine
temperatures are monitored during vehicle opera-
tion. If conditions occur causing the engine or
transmission to overheat, the AutoStick mode will
be canceled, and a code will be set.
Transmission Effects:The 3 position shift sched-
ule that is used in non-AutoStick applications is
substituted while operating in the AutoStick gear
selector position. No limp-in mode occurs.
Possible causes:
> Engine overheat - refer to service manual for
diagnosis and repair
> Transmission Overheat
± Restricted transmission cooling system
± Transmission fluid overfilled
± Radiator fan not functioning properly
± Extended driving in low gear
Note:Strenuous driving conditions may cause the
vehicle to overheat. If the driver operates in or
initiates AutoStick with an overheated vehicle, the
code will be set.
Name of code:P1798 (73) - Deteriorated Transaxle
Fluid
When monitored:At every Fully Electronically
Modulated Converter Clutch (FEMCC) to Partial
Electronically Modulated Converter Clutch (PEM-
CC) transition miles when A/C compressor clutch is
being cycled.
Set condition:The code will be set if vehicle
shudder is detected 20 times when the A/C clutch is
cycled.
Theory of operation:While in 3rd or 4th gear
FEMCC and just before the A/C clutch engages, the
Powertrain Control Module (PCM) requests the
Transmission Control Module (TCM) to momen-
tarily establish PEMCC operation. If vehicle shud-
der is detected during the FEMCC to PEMCC
transition, a counter is incremented. If the count
reaches 20, the trouble code is set. The driver may
14
GENERAL INFORMATION