Ignition system DODGE RAM 1999 Service Owner's Manual
[x] Cancel search | Manufacturer: DODGE, Model Year: 1999, Model line: RAM, Model: DODGE RAM 1999Pages: 1691, PDF Size: 40.34 MB
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Box (DRB) scan tool with appropriate cartridge for system
diagnosis. Other after-market scan tools may be used for
system diagnosis. The following procedure is for DRB scan
tool usage. Use scan tool manufacturer's instruction for
operating scan tool.
NOTE: Ensure battery is fully charged before proceeding with test.
1) Ensure ignition is off. Connect DRB to Data Link Connector
(DLC) located under driver's side of instrument panel. Using scan
tool, display all Diagnostic Trouble Codes (DTCs). Identify DTCs once
retrieved. See DIAGNOSTIC TROUBLE CODES (DTC) & DRB MESSAGES table.
2) If scan tool will not power up, check for loose cable
connections or faulty cable. If cable connections and cable are okay,
check voltage at DLC terminal No. 16. Voltage should be at least 11
volts. If voltage is not as specified, check wiring circuit and
necessary fuses. See WIRING DIAGRAMS.
3) If scan tool displays an error message, RAM TEST FAILURE,
CARTRIDGE ERROR, KEY PAD TEST FAILURE, or LOW OR HIGH BATTERY, this
indicates a scan tool failure.
4) If DTCs are displayed, perform appropriate test(s). See
DIAGNOSTIC TROUBLE CODES (DTC) & DRB MESSAGES table. If no DTCs are
displayed, see TROUBLE SHOOTING in appropriate AUTOMATIC TRANSMISSION
OVERHAUL article.
DIAGNOSTIC TROUBLE CODES (DTC) & DRB MESSAGES
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DTC DRB-III Scan Tool Message
P0711 .................. TRANS TEMP SENSOR, NO TEMP RISE AFTER START
P0712 ............................. TRANS TEMP SENSOR VOLTAGE TO LOW
P0713 ............................ TRANS TEMP SENSOR VOLTAGE TO HIGH
P0720 ..................... LOW OUTPUT SPEED SENSOR RPM ABOVE 15 MPH
P0740 .................... TORQ CONVERTER CLU, NO RPM DROP AT LOCKUP
P0743 ........ TORQUE CONVERTER CLUTCH SOLENOID/TRANS RELAY CIRCUITS
P0748 ........... GOVERNOR PRESSURE SOL CONTROL/TRANS RELAY CIRCUITS
P0751 ....................... OD SWITCH PRESSED (LO) MORE THAN 5 MIN\
P0753 ................ TRANS 3-4 SHIFT SOLENOID/TRANS RELAY CIRCUITS
P0783 ....................... 3-4 SHIFT SOL, NO RPM DROP @ 3-4 SHIFT
P1740 (1) .......................... TCC OR O/D SOLENOID PERFORMANCE
P1756 .................... GOV PRESS NOT EQUAL TO TARGET @ 15-20 PSI
P1757 ...................... GOV PRES ABOVE 3 PSI IN GEAR WITH 0 MPH
P1762 .................... GOV PRESS SEN OFFSET VOLTS TO LOW OR HIGH
P1763 ....................... GOVERNOR PRESSURE SENSOR VOLTS TO HIGH
P1763B ...................... GOVERNOR PRESSURE SENSOR VOLTS TO HIGH
P1764 ........................ GOVERNOR PRESSURE SENSOR VOLTS TO LOW
P1765 ..................... TRANS 12 VOLT SUPPLY RELAY CNTRL CIRCUIT
P1899 .......................... P/N SWITCH STUCK IN PARK OR ON GEAR
( 1) - BR body only.
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CLEARING DIAGNOSTIC TROUBLE CODES
After repairs have been performed, clear DTCs from PCM memory
using scan tool, following scan tool manufacturer's instructions.
NOTE: If malfunction is no longer present after DTC is stored in
PCM memory, the PCM will erase DTC after ignition has been
cycled at least 50 times. DTC may be cleared by using scan
tool. Follow scan tool manufacturer's instructions. DTCs may
also be cleared by disconnecting negative battery cable for a
period of time, but other vehicle control modules may also be
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Diagnostic Procedures
1) On AN and DN bodies, go to next step. On all except AN and
DN bodies, record freeze frame data. Use scan tool to read DTCs. If
DTC SPECIFIC GOOD TRIPS counter is not displayed or displayed count is
not "0", go to step 11). If DTC SPECIFIC GOOD TRIPS counter is
displayed and displayed count is "0", go to next step.
2) 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
transmission temperature signal circuit at White PCM harness connector
C2 and ground circuit at Black PCM harness connector C1. If resistance
is less than 550 ohms, go to step 8). If resistance is 550 ohms or
more, go to next step.
3) If resistance is 550-2300 ohms, go to next step. If
resistance is greater than 2300 ohms, go to DTC P0713: TRANS TEMP
SENSOR VOLTAGE TOO HIGH.
4) Measure resistance of transmission temperature signal
circuit between ground and White PCM harness connector C2. If
resistance is 5 ohms or less, go to step 8). If resistance is greater
than 5 ohms, go to next step.
5) Reconnect all harness connectors. Using scan tool, read
TRANS TEMP voltage. If voltage is less than 1.5 volts, replace PCM. If
voltage is 1.5 volts or greater, go to step 7). On all other bodies,
go to next step.
6) Conditions required to set DTC P0712 are not present at
this time. DTC P0712 sets when transmission temperature sensor voltage
at PCM is less than 1.55 volts for 2.2 seconds. Possible causes are:
shorted transmission temperature sensor wiring, faulty connections,
faulty transmission temperature sensor or faulty PCM. Go to next step.
7) 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.
8) Disconnect transmission solenoid harness connector.
Inspect connector and terminals for damage. Repair as necessary. If
connector and terminals are okay, measure resistance between
transmission temperature signal circuit at White PCM harness connector
C2 and sensor ground circuit at Black PCM harness connector C1. If
resistance is less than 5 ohms, repair transmission temperature signal
circuit for short to ground circuit. If resistance is 5 ohms or
greater, go to next step.
9) Measure resistance between ground and transmission
temperature signal circuit at White PCM harness connector C2. If
resistance is less than 5 ohms, repair transmission temperature signal
circuit for short to ground. If resistance is 5 ohms or greater, go to
next step.
10) Reconnect transmission solenoid harness connector. Remove
transmission oil pan. Disconnect transmission pressure/temperature
sensor harness connector. Measure resistance between transmission
temperature signal circuit at White PCM harness connector C2 and
sensor ground circuit at Black PCM harness connector C1. If resistance
is less than 5 ohms, repair or replace transmission solenoid and
harness assembly. If resistance is 5 ohms or greater, go to next step.
11) Measure resistance between ground and transmission
temperature signal circuit at White PCM harness connector C2. If
resistance is less than 5 ohms, repair or replace transmission
solenoid and harness assembly. If resistance is 5 ohms or greater,
replace transmission pressure/temperature sensor.
DTC P0713: TRANS TEMP SENSOR VOLTAGE TOO HIGH
Circuit Description
Circuit is monitored continuously while key is on, and engine
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between Black PCM harness connector C1 and transmission
pressure/temperature sensor harness connector. If resistance is
greater than 5 ohms, repair or replace transmission solenoid and
harness assembly. If resistance is 5 ohms or less, replace
transmission pressure/temperature sensor.
10) Reconnect all harness connectors. Using scan tool, read
TRANS TEMP voltage. If voltage is greater than 3.76 volts, replace
PCM. If voltage is 3.76 volts or less, conditions required to set DTC
P0713 are not present at this time. DTC P0713 sets when transmission
temperature sensor voltage at PCM is greater than 3.76 volts for 2.2
seconds. Possible causes are: open transmission temperature sensor
wiring, faulty connections, faulty transmission temperature sensor or
faulty PCM. Go to next step.
11) 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 P0720: LOW OUTPUT SPEED SENSOR RPM ABOVE 15 MPH (EXCEPT
BR BODY)
Circuit Description
Circuit is monitored continuously while key is on, and gear
selector is not in Park or Neutral. Code sets if vehicle speed is
above 15 MPH and output shaft speed is below 60 RPM for 2.6 seconds as
measured from vehicle speed sensor.
Possible Causes
* Open output speed sensor ground circuit.
* Damaged ignition wiring.
* Open output speed sensor signal circuit.
* Short to ground in output speed sensor signal circuit.
* Park/Neutral switch code present.
* Malfunctioning sensor.
* Short to ground in output speed sensor ground circuit.
* Malfunctioning PCM.
* OSS harness intermittent defective.
Diagnostic Procedure
1) Using scan tool, check SPECIFIC GOOD TRIPS counter. If DTC
SPECIFIC GOOD TRIPS counter is not displayed or displayed count is not
"0", go to step 12). If DTC SPECIFIC GOOD TRIPS counter is displayed
and displayed count is "0", go to next step.
2) Record all DTCs and one trip failures. If DTC P1899 is
present, repair P/N switch code first. See DTC P1899: P/N SWITCH STUCK
IN PARK OR ON GEAR. If DTC P1899 is not present, go to next step.
3) Raise and support vehicle. Using scan tool, erase DTCs.
See CLEARING DIAGNOSTIC TROUBLE CODES. Start engine. Place engine in
1st gear. Using scan tool, read output speed sensor. Release brake and
let wheels roll, keeping speed below 15 MPH. If scan tool shows 60 RPM
or less, go to step 6). If scan tool shows greater than 60 RPM, go to
next step.
4) While monitoring output speed sensor, wiggle harness
between output speed sensor and PCM. If reading dropped towards zero
while wiggling harness, repair intermittent short or open in harness.
If reading does not drop towards zero while wiggling harness, go to
next step.
5) Using scan tool, erase DTCs. See CLEARING DIAGNOSTIC
TROUBLE CODES. Road test vehicle. If code returns, there are no other
potential causes. Replace PCM. If code does not return, testing is
complete.
6) Turn ignition off. Disconnect PCM and output speed sensor
harness connectors and inspect for damage. Repair as necessary. If no
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problem is found, measure resistance between output speed sensor
terminals. If resistance is 300-1200 ohms, go to next step. If
resistance is not as specified, replace output speed sensor.
7) Reconnect output speed sensor. Measure resistance between
ground and output speed sensor ground circuit at PCM harness
connector. If resistance is greater than 5 ohms, go to next step. If
resistance is not as specified, repair output speed sensor ground
circuit for a short to ground.
8) Measure resistance between ground and output speed sensor
signal circuit at PCM harness connector. If resistance is less than 5
ohms, repair output speed sensor signal circuit for a short to ground.
If resistance is not as specified, go to next step.
9) Measure resistance between output speed sensor signal
circuit and ground circuit at PCM harness connector. If resistance is
300-1200 ohms, replace PCM. If resistance is not as specified, go to
next step.
10) Disconnect output speed sensor harness connector. Measure
resistance of output speed sensor signal circuit between output speed
sensor harness connector and PCM harness connector. If resistance is
greater than 5 ohms, repair open in output speed sensor signal
circuit. If resistance is not as specified, repair open in output
speed sensor ground circuit.
11) Turn ignition on. Measure voltage between ground and
speed sensor ground circuit at PCM harness connector. Place gearshift
lever in each gear position and record voltage at each position. If
voltage is greater than one volt in any gear position, repair speed
sensor ground circuit for a short to power. If voltage is not as
specified, go to next step.
12) Raise and support vehicle. Start engine. Place gearshift
lever in "OD" position. Release brakes and allow wheels to rotate.
Using scan tool, monitor output speed sensor. While monitoring output
speed sensor, wiggle harness between output speed sensor and PCM. If
reading dropped towards zero while wiggling harness, repair
intermittent short or open in harness. If reading does not drop
towards zero while wiggling harness, problem is intermittent. See
INACTIVE DTC CONDITION under SELF-DIAGNOSTIC SYSTEM. Testing is
complete.
DTC P0740: TORQ CONV CLU, NO RPM DROP AT LOCKUP
Circuit Description
Circuit is monitored continuously while key is on, and gear
selector is not in Park or Neutral. Code sets if Torque Converter
Clutch (TCC) does not achieve desired drop in RPM when TCC solenoid is\
near maximum duty cycle. A bad test 3 consecutive times is required to
set code.
Possible Causes
* Misfire trouble code set.
* Vehicle stalls (faulty TCC solenoid).
* TCC shaft seal/seal defective.
* Transmission fluid contaminated.
* TCC solenoid wiring harness defective.
* TCC defective.
* TCC hydraulic circuit damaged.
Diagnostic Procedure
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 10). If DTC SPECIFIC GOOD TRIPS counter is displayed and
displayed count is "0", indicating DTC still exists, go to next step.
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![DODGE RAM 1999 Service Owners Manual 2) If any DTCs listed are present, perform appropriate
test(s). See TORQUE CONVERTOR CLUTCH (TCC) TESTS table. If no DTCs a\
re
present, go to next step.
TORQUE CONVERTOR CLUTCH (TCC) TESTS](/img/12/56915/w960_56915-235.png "DODGE RAM 1999 Service Owners Manual 2) If any DTCs listed are present, perform appropriate
test(s). See TORQUE CONVERTOR CLUTCH (TCC) TESTS table. If no DTCs a\
re
present, go to next step.
TORQUE CONVERTOR CLUTCH (TCC) TESTS")
2) If any DTCs listed are present, perform appropriate
test(s). See TORQUE CONVERTOR CLUTCH (TCC) TESTS table. If no DTCs a\
re
present, go to next step.
TORQUE CONVERTOR CLUTCH (TCC) TESTS
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DTC DTC Message
P0122 (1) ................. THROTTLE POSITION SENSOR VOLTAGE TOO LOW
P0123 ( 1) ................ THROTTLE POSITION SENSOR VOLTAGE TOO HIGH
P1696 ( 1) .......................... PCM FAILURE EEPROM WRITE DENIED
P0743 ........ TORQUE CONVERTOR CLUTCH SOLENOID/TRANS RELAY CIRCUITS
( 2) ........................................................ MISFIRE
P0320 ( 1) ......................... NO CRANK REFERENCE SIGNAL AT PCM
( 1) - See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
( 2) - Perform appropriate misfire DTC test. 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) Start engine. Using scan tool, perform TCC SYSTEM TEST. If
vehicle does not stall, go to step 9). If vehicle stalls, go to next
step.
5) Using scan tool, perform GOV and 3-4 SHIFT VALVE SYSTEM
TEST. Select 4th gear. If vehicle stalls, go to next step. If vehicle
does not stall, go to step 7).
6) Turn ignition off. Replace TCC solenoid. Using scan tool,
perform GOV and 3-4 SHIFT VALVE SYSTEM TEST. Select 4th gear. If
vehicle stalls, problem in internal. Check for blocked passage. If
vehicle does not stall, testing is complete.
7) Turn ignition off. Remove oil pump and inspect reaction
shaft, input shaft and input seal. Repair transmission as necessary.
See appropriate AUTOMATIC TRANSMISSION OVERHAUL article. If
transmission is okay, go to next step.
8) 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.
9) Turn ignition off. Connect a pressure gauge to
transmission cooler OUT port. Start engine. Using scan tool, perform
TCC SYSTEM TEST. If pressure increases when TCC is actuated, go to
next step. If pressure does not increase, repair leaks or blockage in
hydraulic circuit, or repair valve body as necessary.
10) Turn engine off. Remove oil pump and inspect reaction
shaft, input shaft and input seal. Repair transmission as necessary.
See appropriate AUTOMATIC TRANSMISSION OVERHAUL article. If
transmission is okay, there are no other potential causes remaining.
TCC is assumed to be defective. Replace torque converter.
DTC P0743: TORQUE CONV CLUTCH SOLENOID/TRANS RELAY CKT
NOTE: To test transmission temperature sensor, engine and
transmission temperature must be less than 85F (29C).
Circuit Description
Circuit is monitored continuously while key is on. Code sets
if voltage detected on Torque Converter Clutch (TCC) at the Powertrain\
Control Module (PCM) does not match desired voltage.
Possible Causes
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* Fused B+ feed to transmission control circuit open.
* Transmission control relay defective.
* TCC solenoid control circuit open.
* TCC solenoid control circuit shorted to ground.
* TCC wire harness defective.
* Transmission control relay output circuit open.
* Transmission control relay output circuit shorted to
ground.
* PCM defective.
* Solenoid and harness assembly defective.
Diagnostic Procedure (AN & DN Bodies)
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) Using scan tool, perform TCC SYSTEM TEST. If engine
stalls, go to next step. If engine does not stall, go to step 5).
3) Using scan tool, clear DTCs. Start engine and check for
DTCs. Wiggle wiring harness between transmission harness connector and
PCM. If DTC P0743 resets, repair wiring harness as necessary. If DTC
P0743 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. 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 19). If voltage cycles
from zero to greater than 10 volts, go to next step.
6) 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 8).
7) Repair TCC solenoid control circuit for short to voltage.
Reconnect PCM and transmission solenoid harness connector. Start
engine. Using scan tool, perform TCC SYSTEM TEST. If engine stalls,
testing complete. If engine does not stall, replace PCM.
8) Reconnect transmission solenoid harness connector. 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 40 ohms or
less, go to step 12). If resistance is greater than 40 ohms, go to
next step.
9) 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 or replace
transmission solenoid and harness assembly. If resistance is 5 ohms or
greater, go to next step.
10) Remove transmission control relay. 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.
11) Turn ignition off. Disconnect transmission solenoid
harness connector. Measure resistance of TCC solenoid control circuit
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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
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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.
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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
Page 241 of 1691
CONDITION under SELF-DIAGNOSTIC SYSTEM. Testing is complete.
5) 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 18). 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 governor pressure solenoid control circuit at
transmission solenoid harness connector. If voltage is greater than 10
volts, go to step 8). If voltage is 10 volts or less, go to next step.
7) Repair governor pressure solenoid control circuit for
short to ground. 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.
8) Turn ignition off. Reconnect transmission solenoid harness
connector. Measure resistance between ground and governor pressure
solenoid control circuit at White PCM harness connector C2. If
resistance is 5 ohms or less, repair short to ground in governor
pressure solenoid control circuit. If resistance is greater than 5
ohms, 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 governor pressure solenoid control circuit at
White PCM harness connector C2. If resistance is 2.5-5.0 ohms, replace
PCM. If resistance is not 2.5-5.0 ohms, go to next step.
10) Measure resistance between transmission control relay
output circuit at transmission control relay connector and governor
pressure solenoid control circuit at White PCM harness connector C2.
If resistance is greater than 5 ohms, go to next step. If resistance
is 5 ohms or less, go to step 13).
11) Disconnect transmission solenoid harness connector.
Inspect connector and terminals for damage. Repair as necessary. If
connector and terminals are okay, measure resistance of governor
pressure solenoid control circuit between White PCM harness connector
C2 and transmission solenoid harness connector. If resistance is
greater than 5 ohms, repair open governor pressure solenoid control.
If resistance is 5 ohms or less, go to next step.
12) 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 5 ohms or less, repair or replace
transmission solenoid and harness assembly. If resistance is greater
than 5 ohms, replace governor pressure solenoid.
13) Disconnect transmission solenoid harness connector.
Inspect connector and terminals for damage. Repair as necessary. If
connector and terminals are okay, measure resistance between governor
pressure solenoid control circuit and all other circuits at
transmission solenoid harness connector. If resistance is less than 2.
5 ohms between any 2 circuits, go to next step. If resistance is not
less than 2.5 ohms between any 2 circuits, go to step 15).
14) Repair governor pressure solenoid control circuits that
were shorted together. Reconnect all disconnected harness connectors.
Using scan tool, perform GOV and 3-4 SHIFT VALVE SYSTEM TEST. Select