engine DODGE RAM 1999 Service Manual PDF

between White PCM harness connector C2 and transmission solenoid
harness connector. If resistance is less than 5 ohms, replace solenoid
and harness assembly. If resistance is 5 ohms or greater, repair open
in TCC solenoid control circuit.
12) Reconnect transmission control relay. Measure resistance
between ground and TCC solenoid control circuit at White PCM harness
connector C2. If resistance is less than 5 ohms, repair TCC solenoid
control circuit for short to ground. If resistance is 5 ohms or
greater, go to next step.
13) Remove transmission control relay. Inspect connector and
terminals for damage. Repair as necessary. If connector and terminals
are okay, measure resistance between transmission control relay output
circuit at relay and TCC 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.
14) Measure resistance between TCC solenoid control circuit
and all other circuits at solenoid connector. If resistance is less
than 5 ohms between any 2 circuits, go to next step. If resistance is
not less than 5 ohms between any 2 circuits, go to step 17).
15) Reconnect transmission solenoid harness connector.
Measure resistance of TCC solenoid control circuit between ground and
White PCM harness connector C2. If resistance is less than 5 ohms,
replace solenoid and harness assembly. If resistance is 5 ohms or
greater, go to next step.
16) Repair TCC solenoid control circuit shorted to circuits
measured below 5 ohms. Perform appropriate VERIFICATION TEST VER-2A.
See TEST VER-2A. Reconnect all connectors. Start engine. Using scan
tool, perform TCC SYSTEM TEST. If engine stalls, testing complete. If
engine does not stall, replace PCM.
17) Reconnect transmission solenoid harness connector.
Measure resistance of TCC solenoid control circuit between ground and
White PCM harness connector C2. If resistance is less than 5 ohms,
replace solenoid and harness assembly. If resistance is 5 ohms or
greater, go to next step.
18) Repair or replace solenoid and harness assembly. Perform
appropriate VERIFICATION TEST VER-2A. Reconnect all connectors. Start
engine. Using scan tool, perform TCC SYSTEM TEST. If engine stalls,
testing complete. If engine does not stall, replace PCM.
19) Remove transmission control relay. Inspect connector and
terminals for damage. Repair as necessary. If connector and terminals
are okay, turn ignition on. Measure voltage between ground and B+
circuit at transmission control relay harness connector. If voltage is
10 volts or less, repair open fused B+ circuit. If voltage is greater
than 10 volts, go to next step.
20) Turn ignition off. Measure resistance of transmission
control relay output circuit between 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.
21) Measure resistance between ground and transmission
control relay output circuit. 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 & 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. 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.
2) If DTC SPECIFIC GOOD TRIPS counter is not displayed or
displayed count is not "0", go to step 18). If DTC SPECIFIC GOOD TRIPS
counter is displayed and displayed count is "0", indicating DTC still
exists, read and record all DTCs and go to next step.
3) Record freeze frame data to determine conditions when code
was set. Using scan tool, perform TCC SYSTEM TEST. If engine stalls,
go to step 18). If engine does not stall, go to next step.
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 control relay output circuit at
transmission solenoid harness connector. If voltage does not cycle
from zero to greater than 10 volts, go to step 15). If voltage cycles
from zero to greater than 10 volts, go to next step.
5) Turn ignition off. Disconnect White PCM harness connector
C2. Inspect connector and terminals for damage. Repair as necessary.
If connector and terminals are okay, turn ignition on. Measure voltage
between ground and TCC 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 TCC solenoid control circuit for a short to
voltage. Reconnect all harness connectors. Start engine. Using scan
tool, perform TCC SYSTEM TEST. If engine does not stall, replace PCM.
If engine stalls, TCC system is operating properly. Testing is
complete.
7) Turn ignition off. Measure resistance between ground and
TCC solenoid control circuit at White PCM harness connector C2. If
resistance is less than 5 ohms, repair TCC solenoid control circuit
for short to ground. If resistance is 5 ohms or greater, go to next
step.
8) Reconnect transmission solenoid harness connector. Measure
resistance between ground and TCC solenoid control circuit at White
PCM harness connector C2. If resistance is less than 5 ohms, repair or
replace transmission solenoid harness assembly. If resistance is 5
ohms or greater, go to next step.
9) Remove transmission control relay. Inspect 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 TCC
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.
10) If resistance is 40 ohms or less, go to step 12). If
resistance is greater than 40 ohms, go to next step.
11) Measure resistance of TCC solenoid control circuit
transmission solenoid and harness connector and White PCM harness
connector C2. If resistance is less than 5 ohms, replace solenoid and
harness assembly. If resistance is 5 ohms or greater, repair open in
TCC solenoid control circuit.
12) Measure resistance between TCC solenoid control circuit
and all other circuits at solenoid connector. If resistance is less
than 5 ohms between any 2 circuits, go to next step. If resistance is
not less than 5 ohms between any 2 circuits, go to step 14).
13) Repair TCC solenoid control circuit shorted to circuits
measured below 5 ohms. Reconnect all connectors. Start engine. Using
scan tool, perform TCC SYSTEM TEST. If engine stalls, testing
complete. If engine does not stall, replace PCM.
14) Replace solenoid harness inside transmission and solenoid
pack. Reconnect all connectors. Start engine. Using scan tool, perform
TCC SYSTEM TEST. If engine stalls, testing complete. If engine does
not stall, replace PCM.

15) Remove transmission control relay. Inspect connector and
terminals for damage. Repair as necessary. If connector and terminals
are okay, measure resistance of transmission control relay output
circuit between ground and transmission control relay 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, go to next step.
16) Measure resistance of transmission control relay output
circuit between 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.
17) Turn ignition on. Measure voltage between ground and B+
circuit at transmission control relay harness connector. If voltage is
10 volts or less, repair open fused B+ circuit. If resistance is
greater than 10 volts, replace transmission control relay.
18) Record freeze frame data to determine conditions when
code was set. Using freeze frame data and wiring diagram as a guide,
inspect wiring and connectors. Repair wiring harness as necessary. If
wiring and connectors are okay, go to next step.
19) Using scan tool, clear DTCs. Start engine and check for
DTCs. Wiggle wiring harness between TCC solenoid and PCM. If DTC P0743
resets, repair wiring harness as necessary. If DTC P0743 does not
reset, see INACTIVE DTC CONDITION under SELF-DIAGNOSTIC SYSTEM.
Testing is complete.
DTC P0748: GOVERNOR PRESSURE SOL CONTROL/TRANS RELAY CIRCUITS
Circuit Description
Circuit is monitored continuously while key is on. Code sets
if voltage detected on governor pressure solenoid control circuit at
the Powertrain Control Module (PCM) does not match desired voltage for\
4.8 seconds.
Possible Causes
* Fused B+ circuit open.
* Solenoid and harness assembly defective.
* Governor pressure solenoid out of tolerance.
* Transmission control relay defective.
* Governor pressure solenoid control circuit shorted to
ground.
* Governor pressure solenoid harness defective.
* Governor pressure solenoid control circuit open.
* Transmission control relay output circuit open.
* Transmission control relay output circuit shorted to
ground.
* PCM defective.
Diagnostic Procedure (AN & DN Bodies)
1) Using scan tool, read DTCs. If DTC P1765 is set, go to DTC
DTC P1765: TRANS 12-VOLT SUPPLY RELAY CNTRL CIRCUIT. If DTC P1765 is
not set, go to next step.
2) 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 5). If voltage is less than one
volt, go to next step.
3) Using scan tool, erase DTCs. Start engine. Using scan
tool, read DTCs while wiggling wiring harness between governor
pressure solenoid and PCM. If DTC P0748 resets, repair wiring harness
as necessary. If DTC P0748 does not reset, go to next step.
4) Inspect all related wiring and connectors. Repair as
necessary. If wiring and connectors are okay, see INACTIVE DTC

complete.
16) 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.
17) 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.
18) 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.
19) 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.
20) Using scan tool, erase DTCs. Start engine. Using scan
tool, read DTCs while wiggling wiring harness between governor
pressure solenoid and PCM. Note if DTC P0748 resets. If DTC P0748
resets, repair wiring harness as necessary. If DTC P0748 does not
reset, go to next step.
21) Inspect all related wiring and connectors. Repair as
necessary. If wiring and connectors are okay, see INACTIVE DTC
CONDITION under SELF-DIAGNOSTIC SYSTEM. Testing is complete.
DTC P0751: O/D SWITCH PRESSED (LO) MORE THAN 5 MIN
Circuit Description
Circuit is monitored after engine is running for 10 seconds
and reviewed every 440ms. Code sets if overdrive switch is held low
for 5 minutes or more from time of closure or ignition on.
Possible Causes
* Fused B+ circuit open.
* Solenoid and harness assembly defective.
* Governor pressure solenoid out of tolerance.
* Transmission control relay defective.
* Governor pressure solenoid control circuit shorted to
ground.
* Governor pressure solenoid harness defective.
* Governor pressure solenoid control circuit open.
* Transmission control relay output circuit open.
* Transmission control relay output circuit shorted to
ground.
* PCM defective.
Diagnostic Procedure
1) Turn ignition off. Disconnect PCM harness connectors.
Inspect connectors and terminals for damage. Repair as necessary. If
connectors and terminals are okay, measure resistance between ground
and Overdrive (O/D) off switch sense circuit at Gray PCM harness
connector C3. If resistance is less than 5 ohms, go to next step. If
resistance is 5 ohms or greater, go to step 3).
2) Disconnect O/D switch harness connector. Inspect connector
and terminals for damage. Repair as necessary. If connector and
terminals are okay, measure resistance between ground and O/D off

switch sense circuit at O/D switch harness connector. If resistance is
less than 5 ohms, repair short to ground in O/D switch sense circuit.
If resistance is 5 ohms or greater, replace O/D off switch.
3) Conditions required to set DTC P0751 are not present at
this time. DTC P0751 sets if PCM senses O/D off switch input is held
low for 5 minutes or from time of closure or ignition on. Possible
causes are: faulty O/D OFF switch, shorted wire or faulty PCM. Inspect
all related wiring and connectors. Repair as necessary. If wiring and
connectors are okay, see INACTIVE DTC CONDITION under SELF-DIAGNOSTIC
SYSTEM. Testing is complete.
DTC P0753: TRANS 3-4 SHIFT SOLENOID/TRANS RELAY CIRCUITS
Circuit Description
Circuit is monitored continuously while key is on. Code sets
if voltage detected on 3-4 shift solenoid control circuit at the
Powertrain Control Module (PCM) does not match expected voltage.
Possible Causes
* Transmission mechanically defective.
* TPS codes set.
* Transmission 3-4 solenoid wiring harness defective.
* Transmission fluid burnt or oil pan has excessive debris.
* Shift control solenoid circuit shorted to ground.
* Solenoid and harness assembly defective.
* Transmission control relay output circuit open.
* Transmission control relay output circuit shorted to
ground.
* PCM defective.
Diagnostic Procedure (AN & DN 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) Road test vehicle and reach a speed of 50 MPH. Depress
Overdrive (OD) switch 4 times so 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 5). If vehicle shifts between 3rd and 4th gear,
go to next step.
3) Using scan tool, erase DTCs. Start engine. Using scan
tool, read DTCs while wiggling wiring harness between 3-4 shift
solenoid and PCM. If DTC P0753 resets, repair wiring harness as
necessary. If DTC P0753 does not reset, go to next step.
4) 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.
5) 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 16). If voltage switches from zero to greater than
10 volts, go to next step.
6) 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 8).
7) 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

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

connectors and terminals are okay, measure resistance between ground
and 3-4 shift solenoid control circuit at PCM harness connector. If
resistance is 5 ohms or greater, go to next step. If resistance is
less than 5 ohms, repair short to ground in 3-4 shift solenoid
circuit.
6) 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, go to next step.
7) Turn ignition on. Measure voltage between ground and 3-4
shift solenoid control circuit at PCM harness connector. If voltage is
greater than one volt, repair 3-4 shift solenoid control circuit for
short to voltage. If voltage is one volt or less, go to next step.
8) Turn ignition off. 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 26-40
ohms, go to next step. If resistance is not 26-40 ohms or less,
replace 3-4 shift solenoid.
9) Measure resistance between ground and transmission control
relay output circuit at transmission control relay 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, go
to next step.
10) Measure resistance between transmission control relay
output circuit between transmission control relay connector and
transmission solenoid harness connector. If resistance is 5 ohms or
greater, repair open transmission control relay output circuit. If
resistance is less than 5 ohms, go to next step.
11) 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, replace PCM.
12) Disconnect transmission control relay. Inspect connector
and terminals for damage. Repair as necessary. If connector and
terminals are okay, turn ignition on. Replace transmission control
relay. Using scan tool, actuate transmission control relay. Measure
voltage between ground and transmission relay output circuit at
transmission solenoid harness connector. If voltage is greater than 10
volts, replace transmission control relay. If voltage is 10 volts or
less, go to next step.
13) Measure resistance of transmission control relay output
circuit between transmission control relay connector solenoid harness
connector. If resistance is 5 ohms or greater, repair open in
transmission control relay output circuit. If resistance is less than
5 ohms, go to next step.
14) Measure resistance of transmission control relay output
circuit between ground and transmission control relay connector. If
resistance is 5 ohms or greater, go to next step. If resistance is
less than 5 ohms, repair short to ground in transmission control relay
output circuit.
15) 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, test is complete.
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, 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.
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

(1) - See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.








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3) Ensure fuel tank is at least 1/4 full. If fuel level is
too low, correct fuel level and retest. If fuel level is okay, go to
next step.
4) Ensure transfer case is not in low range. Shift transfer
case out of low range. If transfer case is not in low range, go to
next step.
5) Ensure PTO is not engaged. Disengage PTO. If PTO is not
engaged, go to next step.
6) Ensure transmission fluid temperature is above 32
F (0C).
Warm transmission to normal operating temperature. If transmission
fluid temperature is above 32
F (0C), go to next step.
7) Turn ignition on. Using scan tool, build a custom display
with engine RPM, output shaft SPD, TCC solenoid, O/D solenoid and
throttle position. Set overdrive to off position. Road test vehicle
and reach a steady speed of 55 MPH with a minimum throttle opening
voltage of 1.15 volts for 20 seconds. Note shift patterns while
vehicle is attaining speed. If engine RPM is within 60 RPM of output
shaft speed RPM, go to next step. If engine RPM is not within 60 RPM
of output shaft speed RPM, go to step 15).
8) If output shaft speed RPM is greater than engine RPM, go
to next step. If output shaft speed RPM is equal to or less than
engine RPM, go to step 15).
9) Road test vehicle and reach a steady speed of 55 MPH and
engage overdrive. If engine RPM is 69 percent of output shaft speed,
go to step 15). If engine RPM is not 69 percent of output shaft speed,
go to next step.
10) 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 13).
11) 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.
12) Drain transmission fluid and remove oil pan. If
transmission fluid is burnt or has excessive debris, repair as
necessary. If transmission fluid is okay, go to step 23).
13) 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.
14) Leave gauges connected. Replace 3-4 shift solenoid. 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, 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.
15) 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.
16) Start engine. Using scan tool, perform TCC SYSTEM TEST.