The following items may be area of concern:
ï¬Other transmission-related DTCs are set.
ï¬Solenoid pack connector 5-volt supply circuit open.
ï¬Sensor signal circuit has short to ground, short to voltage or open.
ï¬Governor pressure sensor defective.
ï¬Transmission fluid burnt or oil pan contains excessive debris.
ï¬Governor pressure out of range.
ï¬Transmission leaking internally.
ï¬Defective PCM.
ï¬Defective valve body.
1.Using scan tool, read DTCs. If good trip counter for DTC P1756 is not
displayed or displayed count is not zero, go to step 25. If good trip
counter is displayed and displayed count is zero, go to next step.
2.Repair any other transmission-related DTCs before proceeding. If no other transmission-related DTCs exist, go to next step.
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. Allow engine to reach normal operating temperature. Set
parking brake, depress brake pedal and place gearshift lever in
"D" position. Using scan tool, observe governor
pressure sensor pressure. If pressure is greater than 3 psi (.2 kg/cm 2
), go to next step. If pressure is 3 psi (.2 kg/cm 2 ) or less, go to
step 20.
5.Turn ignition off. Install a pressure gauge at transmission governor
pressure test port. Start engine. With gearshift lever in
"D" position, observe gauge pressure. If pressure is 5
psi (.3 kg/cm 2 ) or more, go to step 23. If pressure is less than 5
psi (.3 kg/cm 2 ), go to next step.
6.Turn ignition off. Disconnect transmission solenoid assembly
connector. Turn ignition on. Measure voltage between ground and 5-volt
supply circuit at transmission solenoid harness connector terminal No.
2. If voltage is 4.5-5.5 volts, go to next step. If voltage is not
4.5-5.5 volts, go to step 19.
7.Turn ignition off. Disconnect PCM harness connector C2 (White).
Measure resistance of governor pressure sensor signal circuit between
transmission solenoid harness connector terminal No. 4 and PCM harness
connector C2 (White) terminal No. 29. If resistance is less than 5 ohms,
go to next step. If resistance is 5 ohms or more, repair governor
pressure sensor signal circuit for open.
8.Disconnect PCM harness connector C1 (Black). Measure resistance of
sensor ground circuit between transmission solenoid harness connector
terminal No. 3 and PCM harness connector C1 (Black) terminal No. 4. If
resistance is less than 5 ohms, go to next step. If resistance is 5 ohms
or more, repair sensor ground circuit for open.
9.Measure resistance of governor pressure sensor signal circuit between
ground and transmission solenoid harness connector terminal No. 4. If
resistance is less than 5 ohms, repair signal circuit for short to
ground. If resistance is 5 ohms or more, go to next step.
10.Measure resistance between sensor signal circuit and sensor ground
circuit at transmission solenoid harness connector terminals No. 3 and
4. If resistance is less than 5 ohms, repair governor pressure sensor
circuit for short to sensor ground circuit. If resistance is 5 ohms or
more, go to next step.
11.Turn ignition on. Measure voltage of governor pressure sensor signal
circuit between ground and transmission solenoid assembly connector
terminal No. 4. If voltage is one volt or less, go to next step. If
voltage is more than one volt, repair sensor signal circuit for short to
voltage.
12.Turn ignition off. Ensure transmission solenoid harness connector is
disconnected. Remove transmission oil pan. Disconnect governor
pressure/temperature sensor harness connector. Inspect connector and
terminals for damage. Repair as necessary. Measure resistance of
governor pressure sensor 5-volt supply circuit between governor
pressure/temperature sensor harness connector terminal
"A" and transmission solenoid harness connector
terminal No. 2. If resistance is less than 5 ohms, go to next step. If
resistance is 5 ohms or more, replace transmission solenoid assembly
(internal transmission harness).
13.Measure resistance of sensor ground circuit between governor
pressure/temperature sensor harness connector terminal
"D" and transmission solenoid harness connector
terminal No. 3. If resistance is less than 5 ohms, go to next step. If
resistance is 5 ohms or more, replace transmission solenoid assembly
(internal transmission harness).
14.Measure resistance of governor pressure sensor signal circuit between
governor pressure/temperature sensor harness connector terminal
"B" and transmission solenoid harness connector
terminal No. 4. If resistance is less than 5 ohms, go to next step. If
resistance is 5 ohms or more, replace transmission solenoid assembly
(internal transmission harness).
15.Measure resistance of governor pressure sensor signal circuit between
ground and governor pressure/temperature sensor harness connector
terminal "B". If resistance is less than 5 ohms,
replace transmission solenoid assembly (internal transmission harness).
If resistance is 5 ohms or more, go to next step.
16.Measure resistance between governor pressure sensor signal circuit
and sensor ground circuit at governor pressure/temperature sensor
harness connector terminals "B" and
"D". If resistance is less than 5 ohms, replace
transmission solenoid assembly (internal transmission harness). If
resistance is 5 ohms or more, go to next step.
17.Reconnect transmission solenoid assembly harness connector. Turn
ignition on. Measure voltage of governor pressure sensor signal circuit
between ground and governor pressure/temperature sensor harness
connector terminal "B". If voltage is more than one
volt, replace transmission solenoid assembly (internal transmission
harness). If voltage is one volt or less, go to next step.
18.Turn ignition off. Using DVOM, backprobe governor pressure sensor
signal circuit at PCM harness connector C2 (White) terminal No. 29.
Start and idle engine. Place gearshift lever in "N"
position. Using scan tool, observe governor pressure sensor voltage.
Compare scan tool value with DVOM voltage. If voltages match, replace
governor pressure/temperature sensor. If voltages do not match, replace
PCM.
19.Turn ignition off. Ensure transmission solenoid harness connector is
disconnected. Disconnect PCM harness connector C2 (White). Measure
resistance of 5-volt supply circuit between transmission solenoid
harness connector terminal No. 2 and PCM harness connector C2 (White)
terminal No. 31. If resistance is less than 5 ohms, replace PCM. If
resistance is 5 ohms or more, repair 5-volt supply circuit for open.
NOTE: Removing transmission control relay in the following step may set other DTCs. Disregard these DTCs.
.
20.Ensure engine is at normal operating temperature. Place gearshift lever in "P" position. With engine running
,
remove transmission control relay from underhood Power Distribution
Center (PDC) or Integrated Power Module (IPM), as applicable. Depress
brake pedal and place gearshift lever in "D" position.
Using scan tool, observe governor pressure sensor pressure. If pressure
is 40-55 psi (2.8-3.9 kg/cm 2 ), go to next step. If pressure is not
40-55 psi (2.8-3.9 kg/cm 2 ), go to step 22.
21.Turn ignition off. Replace governor pressure solenoid. Test drive
vehicle at 25-30 MPH. Using scan tool, monitor governor actual pressure
and target pressure. If pressures do not remain constant within 5 psi
(.3 kg/cm 2 ) of each other, repair internal transmission leakage
problem. If pressures remain constant within 5 psi (.3 kg/cm 2 ) of each
other, testing is complete.
22.Turn ignition off. Connect a 0-300 psi (0-21 kg/cm 2 ) pressure gauge
to transmission governor pressure test port. Ensure engine and
transmission are at normal operating temperature. Place gearshift lever
in "P" position. Start and idle engine. With engine running,
remove transmission control relay from underhood Power Distribution
Center (PDC) or Integrated Power Module (IPM), as applicable. Depress
brake pedal and place gearshift lever in "D" position.
Observe governor pressure. If pressure is 40-55 psi (2.8-3.9 kg/cm 2 ),
testing is complete. If pressure is not 40-55 psi (2.8-3.9 kg/cm 2 ),
go to next step.
23.Turn engine off. Install transmission control relay. Drain
transmission fluid and remove oil pan. Inspect pan for burnt oil and
debris. Repair transmission as necessary. If transmission is okay, go to
next step.
24.Replace governor pressure solenoid. Start engine.
Observe gauge pressure. If pressure is less than 5 psi (.3 kg/cm 2 ),
testing is complete. If pressure is 5 psi (.3 kg/cm 2 ) or more, replace
valve body.
25.Conditions required to set DTC are currently not present. Inspect all
applicable connectors and terminals for damage. Repair as necessary.
Testing is complete.
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This is one of two things, if the truck goes into drive and moves then you have trany problems and may need to have it rebuilt, if there is no movement in reverse or drive then it could be the transfer case or trany.
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