
1st gear and read governor pressure voltage. If voltage is one volt or
greater, replace PCM. If voltage is less than one volt, test is
complete.
15) Drain transmission fluid and remove oil pan. Disconnect
governor pressure solenoid harness connector. Inspect connector and
terminals for damage. Repair as necessary. If connector and terminals
are okay, measure resistance across governor pressure solenoid
terminals. If resistance is 2.5 ohms or less, go to next step. If
resistance is greater than 2.5 ohms, go to step 17).
16) Replace governor pressure solenoid. Replace oil pan and
fill with fluid. Reconnect all disconnected harness connectors. Using
scan tool, perform GOV and 3-4 SHIFT VALVE SYSTEM TEST. Select 1st
gear and read governor pressure voltage. If voltage is one volt or
greater, replace PCM. If voltage is less than one volt, test is
complete.
17) Repair or replace transmission solenoid and harness
assembly. Reconnect all disconnected harness connectors. Using scan
tool, perform GOV and 3-4 SHIFT VALVE SYSTEM TEST. Select 1st gear and
read governor pressure voltage. If voltage is one volt or greater,
replace PCM. If voltage is less than one volt, test is complete.
18) Remove transmission control relay. Inspect transmission
control relay connector and terminals for damage. Repair as necessary.
If connector and terminals are okay, turn ignition on. Measure voltage
between ground and fused B+ circuit at transmission control relay
connector. If voltage is 10 volts or less, repair open fused B+
circuit. If voltage is greater than 10 volts, go to next step.
19) Turn ignition off. Measure resistance of transmission
control relay output circuit at transmission control relay connector
and TCC solenoid harness connector. If resistance is greater than 5
ohms, repair open transmission control relay output circuit. If
resistance is 5 ohms or less, go to next step.
20) Measure resistance between ground and transmission
control relay output circuit at transmission solenoid harness
connector. If resistance is less than 5 ohms, repair open in
transmission control relay output circuit. If resistance is 5 ohms or
greater, replace transmission control relay.
Diagnostic Procedure (AB, BR & WJ Bodies)
NOTE: On WJ body, if all solenoid codes, P0743, P0748 and P0753 are
set, go to test DTC P1765: TRANS 12-VOLT SUPPLY RELAY CNTRL
CIRCUIT before proceeding.
1) Using scan tool, read DTCs. On BR and WJ bodies, go to
next step. On AB body, if DTC SPECIFIC GOOD TRIPS counter is not
displayed or displayed count is not "0", go to step 20). If DTC
SPECIFIC GOOD TRIPS counter is displayed and displayed count is "0",
indicating DTC still exists, go to next step.
2) If DTC P1765 is also set, go to DTC DTC P1765: TRANS 12-
VOLT SUPPLY RELAY CNTRL CIRCUIT. If DTC P1765 is not set, go to next
step.
3) Using scan tool, perform GOV and 3-4 SHIFT VALVE SYSTEM
TEST. Select 1st gear and read governor pressure voltage. If voltage
is one volt or greater, go to step 20). If voltage is less than one
volt, go to next step.
4) Turn ignition off. Disconnect transmission solenoid
harness connector. Turn ignition on. Using scan tool, actuate
transmission control relay. Measure voltage between ground and
transmission relay output circuit at transmission solenoid harness
connector. If voltage does not switch from zero to greater than 10
volts, go to step 17). If voltage switches from zero to greater than
10 volts, go to next step.
5) Turn ignition off. Disconnect PCM harness connectors.

resistance is 5 ohms or less, go to next step.
18) Measure resistance between ground and transmission
control relay output circuit at transmission solenoid harness
connector. If resistance is less than 5 ohms, repair short to ground
in transmission control relay output circuit. If resistance is 5 ohms
or greater, replace transmission control relay.
Diagnostic Procedure (AB & BR Bodies)
1) If DTC P1765 is also set, go to DTC P1765: TRANS 12-VOLT
SUPPLY RELAY CNTRL CIRCUIT. If DTC P1765 is not set, go to next step.
2) If DTC SPECIFIC GOOD TRIPS counter is not displayed or
displayed count is not "0", go to step 16). If DTC SPECIFIC GOOD TRIPS
counter is displayed and displayed count is "0", go to next step.
3) Record freeze frame data to determine conditions when code
was set. Road test vehicle and reach a speed of 50 MPH. Depress
Overdrive (OD) switch 4 times so that vehicle attempts to shift from
4th gear to 3rd gear and back. If vehicle does not shift between 3rd
and 4th gear, go to next step. If vehicle shifts between 3rd and 4th
gear, go to step 16).
4) Turn ignition off. Disconnect transmission solenoid
harness connector. Inspect connector and terminals for damage. Repair
as necessary. If connector and terminals are okay, turn ignition on.
Using scan tool, actuate transmission control relay. Measure voltage
between ground and transmission relay output circuit at transmission
solenoid harness connector. If voltage does not switch from zero to
greater than 10 volts, go to step 13). If voltage switches from zero
to greater than 10 volts, go to next step.
5) Turn ignition off. Disconnect PCM harness connectors.
Inspect connectors and terminals for damage. Repair as necessary. If
connectors and terminals are okay, turn ignition on. Measure voltage
between ground and 3-4 shift solenoid control circuit at transmission
solenoid harness connector. If voltage is greater than 10 volts, go to
next step. If voltage is 10 volts or less, go to step 7).
6) Repair 3-4 shift solenoid control circuit for short to
voltage. Reconnect all disconnected harness connectors. Road test
vehicle and reach a speed of 50 MPH. Depress Overdrive (OD) switch 4
times so that vehicle attempts to shift from 4th gear to 3rd gear and
back. If vehicle does not shift between 3rd and 4th gear, replace PCM.
If vehicle shifts between 3rd and 4th gear, testing is complete.
7) Turn ignition off. Measure resistance between ground and
3-4 shift solenoid control circuit at White PCM harness connector C2.
If resistance is less than 5 ohms, repair short to ground in 3-4 shift
solenoid control circuit. If resistance is 5 ohms or greater, go to
next step.
8) Turn ignition off. Measure resistance between ground and
3-4 shift solenoid control circuit at White PCM harness connector C2.
If resistance is less than 5 ohms, repair short to ground in 3-4 shift
solenoid control circuit. If resistance is 5 ohms or greater, go to
next step.
9) Remove transmission control relay. Inspect transmission
control relay connector and terminals for damage. Repair as necessary.
If connector and terminals are okay, measure resistance between
transmission control relay output circuit at transmission control
relay connector and 3-4 shift solenoid control circuit at White PCM
harness connector C2. If resistance is greater than 40 ohms, go to
next step. If resistance is 40 ohms or less, go to step 12).
10) Measure resistance between transmission control relay
output circuit at transmission control relay connector and 3-4 shift
solenoid control circuit at White PCM harness connector C2. If
resistance is 26-40 ohms, replace PCM. If resistance is not 26-40
ohms, go to next step.
11) Measure resistance of 3-4 shift solenoid circuit between
White PCM harness connector C2 and transmission solenoid harness

connector. If resistance is 5 ohms or greater, repair open 3-4 shift
solenoid circuit. If resistance is less than 5 ohms, replace
transmission solenoid and harness assembly.
12) Measure resistance between transmission control relay
output circuit at transmission control relay connector and 3-4 shift
solenoid control circuit at White PCM harness connector C2. If
resistance is 26-40 ohms, replace PCM. If resistance is not 26-40
ohms, test is complete.
13) Remove transmission control relay. Inspect transmission
control relay connector and terminals for damage. Repair as necessary.
If connector and terminals are okay, turn ignition on. Measure voltage
between ground and fused B+ circuit at transmission control relay
connector. If voltage is 10 volts or less, repair open fused B+
circuit. If voltage is greater than 10 volts, go to next step.
14) Turn ignition off. Measure resistance of transmission
control relay output circuit at transmission control relay connector
and TCC solenoid harness connector. If resistance is greater than 5
ohms, repair open transmission control relay output circuit. If
resistance is 5 ohms or less, go to next step.
15) Measure resistance between ground and transmission
control relay output circuit at transmission solenoid harness
connector. If resistance is less than 5 ohms, repair short to ground
in transmission control relay output circuit. If resistance is 5 ohms
or greater, replace transmission control relay.
16) Using scan tool, erase DTCs. Start engine. Attempt to
duplicate data and reset code. Using wiring diagram as a guide,
inspect wiring and connectors. Repair wiring harness as necessary. If
wiring and connectors are okay, go to next step.
17) Wiggle wiring harness between TCC solenoid and PCM. Note
if DTC P0753 resets. If DTC P0753 resets, repair wiring harness as
necessary. If DTC P0753 does not reset, replace PCM and see INACTIVE
DTC CONDITION under SELF-DIAGNOSTIC SYSTEM. Testing is complete.
Diagnostic Procedure (WJ Body)
NOTE: If all solenoid codes, P0743, P0748 and P0753 are set, go to
test DTC P1765: TRANS 12-VOLT SUPPLY RELAY CNTRL CIRCUIT
before proceeding.
1) Using scan tool, read DTCs. If DTC SPECIFIC GOOD TRIPS
counter is not displayed or displayed count is not "0", go to next
step. If DTC SPECIFIC GOOD TRIPS counter is displayed and displayed
count is "0", go to step 16).
2) Road test vehicle and reach a speed of 50 MPH. Depress
Overdrive (OD) switch 4 times so that vehicle attempts to shift from
4th gear to 3rd gear and back. If vehicle does not shift between 3rd
and 4th gear, go to step 4). If vehicle shifts between 3rd and 4th
gear, go to next step.
3) Record freeze frame data to determine conditions when code
was set. Using wiring diagram as a guide, inspect wiring and
connectors. Repair wiring harness as necessary. If wiring and
connectors are okay, see INACTIVE DTC CONDITION under SELF-DIAGNOSTIC
SYSTEM. Testing is complete.
4) Turn ignition off. Disconnect transmission solenoid
harness connector. Inspect connector and terminals for damage. Repair
as necessary. If connector and terminals are okay, turn ignition on.
Using scan tool, actuate transmission control relay. Measure voltage
between ground and transmission relay output circuit at transmission
solenoid harness connector. If voltage does not switch from zero to
greater than 10 volts, go to step 12). If voltage switches from zero
to greater than 10 volts, go to next step.
5) Turn ignition off. Disconnect PCM harness connectors.
Inspect connectors and terminals for damage. Repair as necessary. If

replace PCM and see INACTIVE DTC CONDITION under SELF-DIAGNOSTIC
SYSTEM. Testing is complete.
DTC P0783: 3-4 SHIFT SOL, NO RPM DROP @ 3-4 SHIFT
Circuit Description
Circuit is monitored continuously while key is on and engine
running. Code sets if expected RPM drop does not occur within 4
seconds of requested gear change by PCM. Test must fail 3 times to set
code.
Possible Causes
* Transmission mechanically defective.
* TPS codes set.
* Transmission 3-4 solenoid wiring harness defective.
* Transmission fluid burnt or oil pan has excessive debris.
Diagnostic Procedures
1) Using scan tool, read DTCs. On all bodies except AB and WJ
bodies, go to next step. On AB and WJ bodies, if DTC SPECIFIC GOOD
TRIPS counter is not displayed or displayed count is not "0", go to
step 6). If DTC SPECIFIC GOOD TRIPS counter is displayed and displayed
count is "0", indicating DTC still exists, go to next step.
2) If any DTCs listed are present, perform appropriate
test(s). See 3-4 SHIFT SOLENOID TESTS table. If no DTCs are present,
go to next step.
3-4 SHIFT SOLENOID TESTS
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DTC Message Test
NO CAM SIGNAL AT PCM ..................................... ( 1) P0340
P/N SWITCH STUCK IN PARK OR IN GEAR .......................... P1899
Any Throttle Position Sensor (TPS) DTC ......................... ( 1)
TORQUE CONVERTOR CLUTCH SOLENOID/TRANS RELAY CIRCUITS ........ P0743
TRANS 12-VOLT SUPPLY RELAY CNTRL CIRCUIT ..................... P1765
TRANS 3-4 SHIFT SOLENOID/TRANS RELAY CIRCUITS ................ P0753
( 1) - See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
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3) Check transmission fluid for proper level and for any
debris. Fill or repair transmission as necessary. If fluid level and
condition are okay, go to next step.
4) Connect a 0-300 psi (0-21 kg/cm
) pressure gauge to
transmission Overdrive (O/D) clutch pressure test port. Connect a
second 0-300 psi (0-21 kg/cm
) pressure gauge to transmission governor
pressure test port. See appropriate AUTOMATIC TRANSMISSION OVERHAUL
article. Ensure engine and transmission are at normal operating
temperature. With an assistant, test drive vehicle. Using scan tool,
select GOV and 3-4 SHIFT VALVE SYSTEM TEST. Select 4th gear while
monitoring pressure gauge. Governor pressure should rise to greater
than 20 psi (1.4 kg/cm
) and O/D pressure should rise to greater than
40 psi (2.8 kg/cm). If pressures are as specified, go to next step.
If pressures are not as specified, go to step 8).
5) Using wiring diagram as a guide, inspect wiring and
connectors. Repair wiring harness as necessary. If wiring and
connectors are okay, go to next step.
6) Using scan tool, erase DTCs. Start engine. Road test
vehicle at 0-55 MPH with a constant 20 percent throttle. Repeat road
test 4 times. Note if DTC P0783 resets. If DTC P0783 resets, repair
wiring harness as necessary. If DTC P0783 does not reset, go to next

step.
7) Turn engine off. Drain transmission fluid and remove oil
pan. Inspect oil pan for burnt oil and debris. Repair transmission as
necessary. See appropriate AUTOMATIC TRANSMISSION OVERHAUL article. If
transmission is okay, no problem is found at this time, see INACTIVE
DTC CONDITION under SELF-DIAGNOSTIC SYSTEM. Testing is complete.
8) Leave gauges connected. Replace 3-4 shift solenoid.
Replace transmission pan and fill with fluid. Start engine and allow
engine and transmission to reach normal operating temperature. Using
scan tool, select GOV and 3-4 SHIFT VALVE SYSTEM TEST. Select 4th gear
while monitoring pressure gauges. Governor pressure should rise to
greater than 20 psi (1.4 kg/cm
) and O/D pressure should rise to
greater than 40 psi (2.8 kg/cm). If pressures are as specified, no
problem is found at this time. Testing is complete. If pressures are
not as specified, see appropriate AUTOMATIC TRANSMISSION OVERHAUL
article, paying attention to seals and clutches related to O/D clutch.
DTC P1740: TCC OR O/D SOLENOID PERFORMANCE (BR BODY - DIESEL)
Circuit Description
Torque Converter Clutch (TCC) and overdrive clutch are tested\
when Powertrain Control Module (PCM) requests TCC engagement in 3rd
gear and overdrive. Code will set if expected RPM drop is not achieved
while attempting to engage TCC and/or overdrive. Code indicates
malfunctioning torque converter or overdrive clutch.
Possible Causes
* Fluid level or quality problem.
* Transmission wiring and connector defective.
* Transmission mechanically defective.
* Low fuel level.
* Trans temperature below 32
.
* Transfer case is in low range.
* Engine RPM trouble codes set.
* Misfire trouble code set (DTCs P0300-P0306).
* Output shaft speed trouble code set.
* PTO is engaged.
* TPS codes set (DTCs P0121-P0123).
* Torque converter defective.
Diagnostic Procedures
1) Using scan tool, read DTCs. If DTC SPECIFIC GOOD TRIPS
counter is not displayed or displayed count is not "0", go to step
16). If DTC SPECIFIC GOOD TRIPS counter is displayed and displayed
count is "0", go to next step.
2) If any DTCs listed are present, perform appropriate
test(s). See TCC OR O/D SOLENOID TESTS table. If no DTCs are present,
go to next step.
TCC OR O/D SOLENOID TESTS
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DTC Message Test
CAMSHAFT POSITION SENSOR SIGNAL .......................... ( 1) P0341
P/N SWITCH STUCK IN PARK OR IN GEAR .......................... P1899
Any Throttle Position Sensor (TPS) DTC ......................... ( 1)
Any Misfire DTC ................................................ ( 1)
Any Engine RPM DTC ............................................. ( 1)
Any Output Shaft Speed Sensor DTC .............................. ( 1)
TRANS 12-VOLT SUPPLY RELAY CNTRL CIRCUIT ..................... P1765
TORQUE CONVERTOR CLUTCH SOLENOID/TRANS RELAY CIRCUITS ........ P0743
TRANS 3-4 SHIFT SOLENOID/TRANS RELAY CIRCUITS ................ P0753