DTC P0756 2-3 Shift Solenoid Valve Performance. GMC Truck Jimmy

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 1998 🢒 Jimmy - 2WD 🢒 Transmission/Transaxle 🢒 Automatic Transmission - 4L60-E 🢒 DTC P0756 2-3 Shift Solenoid Valve Performance

DTC P0756 2-3 Shift Solenoid Valve Performance 2.2L

Automatic Transmission Components
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice

Circuit Description

The 2-3 Shift Solenoid Valve (2-3 SS Valve) controls the fluid flow acting on the 2-3 shift valves. The 2-3 SS Valve is a normally-open exhaust valve that is used with the 1-2 Shift Solenoid Valve (1-2 SS Valve) in order to allow four different shifting combinations.

When the PCM detects a 1-2-2-1 or a 4-3-3-4 shift pattern, depending on the state of the mechanical failure, then DTC P0756 sets. DTC P0756 is a type A DTC.

Conditions for Setting the DTC

•	No TP Sensor DTCs P0122 or P0123.

•	No VSS Assy. DTCs P0502 or P0503.

•	No TCC Sol. Valve DTC P0740.

•	No TCC Stuck ON DTC P0742.

•	No 1-2 SS Valve DTC P0753.

•	No 2-3 SS Valve DTC P0758.

•	No 3-2 SS Valve Assy. DTC P0785.

•	No TFP Val. Position Sw. DTC P1810.

•	No TCC PWM Sol. Valve DTC P1860.

•	The vehicle speed is greater than 8 km/h (5 mph).

•	The gear range is D4.

•	The engine vacuum is 0-105 kPa.

•	The engine speed is greater than 450 RPM for 5 seconds.

•	Not in fuel cutoff.

•	The transmission fluid temperature is 20-130°C (68-266°F).

•	All of the above conditions are met three times and the combination of Conditions 1 and 2 or Conditions 2 and 3 occurs three times.

Condition 1

•	The TP angle is greater than 25%.

•	First gear is commanded for 2 seconds.

•	The engine torque is 40-400 lb ft.

•	The speed ratio is 0.7-3.0 (speed ratio is engine speed divided by output speed).

•	The transmission output speed is 400-1500 RPM.

•	The TCC slip speed is -100 to -3000 RPM for 1.5 seconds.

Condition 2

•	The TP angle is 10-50%.

•	The TP angle is within +/- 7%.

•	Third gear is commanded for 2-6 seconds.

•	The engine torque is 40-400 lb ft.

•	The speed ratio in 3rd gear does not drop by more than 0.35 from the last speed ratio in 2nd gear.

•	The TCC slip speed in 3rd gear is 300 RPM greater than the last TCC slip speed in 2nd gear.

•	All conditions met for 1.5 seconds.

Condition 3

•	The TP angle is greater than 10%.

•	Fourth gear is commanded for 1 second.

•	The engine torque is 40-400 lb ft.

•	The speed ratio is 1.68-3.5.

•	The TCC slip speed is 1000-4000 RPM for 1 second.

•	The transmission output speed is 1400-3000 RPM.

Action Taken When the DTC Sets

•	The PCM illuminates the Malfunction Indicator Lamp (MIL).

•	The PCM commands 3rd gear only.

•	The PCM inhibits TCC engagement.

•	The PCM commands maximum line pressure.

•	The PCM freezes shift adapts from being updated.

•	DTC P0756 stores in PCM history.

Conditions for Clearing the MIL/DTC

•	The PCM turns OFF the MIL after three consecutive trips without a failure reported.

•	A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.

•	The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.

Diagnostic Aids

•	Verify that the transmission meets the specifications in the 4L60-E Shift Speed table.

•	Other internal transmission failures may cause more than one shift to occur.

•	Refer to the Shift Solenoid Valve State and Gear Ratio table.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

This step verifies that the scan tool commanded all shifts, and all shift solenoid valves responded correctly, but all the shifts did not occur.

DTC P0756 2-3 Shift Solenoid Valve -- Performance (2.2L)

Step

Action

Value(s)

Yes

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

Install the Scan Tool .
With the engine OFF, turn the ignition switch to the RUN position.

Important: Before clearing the DTC(s), use the scan tool in order to record the Freeze Frame and Failure Records for reference. Using the Clear Info function will erase the stored Freeze Frame and Failure Records from the PCM.

Record the DTC Freeze Frame and Failure Records, then clear the DTC(s).
Drive the vehicle in D4 range, under the following conditions:

Accelerate the vehicle, ensuring that the PCM commands 1st, 2nd, 3rd and 4th gears.

Did you detect a 1-2-2-1 or 4-3-3-4 shift pattern?

Go to Step 3

Go to Diagnostic Aids

Inspect the shift solenoid/hydraulic circuit for the following conditions:

•	An internal malfunction

•	Damaged seals on the solenoid valves

Refer to Shift Solenoid Leak Test.

Did you find and correct the condition?

Go to Step 4

In order to verify your repair, perform the following procedure:

Select DTC.
Select Clear Info.
Drive the vehicle in D4 under the following conditions (only if traffic and road conditions permit):

•	Hold the throttle at 50% and accelerate to 64 km/h (40 mph).

•	Stop the vehicle, engine idling.

•	Hold the throttle at 15% and accelerate to 80 km/h (55 mph).

Select Specific DTC. Enter DTC P0756.

Has the test run and passed?

System OK

Go to Step 1

DTC P0756 2-3 Shift Solenoid Valve Performance 4.3L

Automatic Transmission Components
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice

Circuit Description

The 2-3 Shift Solenoid Valve (2-3 SS Valve) controls the fluid flow acting on the 2-3 shift valves. The solenoid is a normally-open exhaust valve. With the 1-2 Shift Solenoid Valve (1-2 SS Valve), the 2-3 SS Valve allows four different shifting combinations.

When the VCM detects a 1-2-2-1 or a 4-3-3-4 shift pattern, depending on the state of the mechanical failure, then DTC P0756 sets. DTC P0756 is a type A DTC.

Conditions for Setting the DTC

•	No TP Sensor DTCs P0122 or P0123.

•	No VSS Assy. DTCs P0502 or P0503.

•	No TFT Sensor DTCs P0711, P0712 or P0713.

•	No TCC Sol. Valve DTC P0740.

•	No TCC Stuck ON DTC P0742.

•	No 1-2 SS Valve DTC P0753.

•	No 2-3 SS Valve DTC P0758.

•	No 3-2 SS Valve Assy. DTC P0785.

•	No TFP Val. Position Sw. DTC P1810.

•	No TCC PWM Sol. Valve DTC P1860.

•	The vehicle speed is greater than 8 km/h (5 mph).

•	The gear range is D4.

•	The engine vacuum is 0-105 kPa.

•	The engine torque is 5-450 lb ft.

•	The engine speed is greater than 450 RPM for 5 seconds.

•	Not in fuel cutoff.

•	The transmission fluid temperature is 20-130°C (68-266°F).

•	All of the above conditions are met three times and the combination of Conditions 1 and 2 or Conditions 2 and 3 occurs three times.

Condition 1

•	The TP angle is greater than 15%.

•	First gear is commanded for 2 seconds.

•	The speed ratio is 0.5 to 3.0 (speed ratio is the engine speed divided by the output speed).

•	The transmission output speed is 400-1500 RPM.

•	The TCC slip speed is -100 to -3000 RPM for 1 second.

Condition 2

•	The TP angle is 13-50%.

•	The TP angle is within +/- 7%.

•	Third gear is commanded for 2 to 5 seconds.

•	The speed ratio in 3rd gear does not drop more than 0.3 from the last speed ratio in 2nd gear.

•	The TCC slip speed in 3rd gear remains 300 RPM higher than the last TCC slip speed in 2nd gear.

•	All conditions met for 1.5 seconds.

Condition 3

•	The TP angle is greater than 13%.

•	Fourth gear is commanded for 1 second.

•	The speed ratio is 2.05 to 8.0.

•	The transmission output speed is 1400-2500 RPM.

•	The TCC slip speed is 1000-4000 RPM for 1 second.

Action Taken When the DTC Sets

•	The VCM illuminates the Malfunction Indicator Lamp (MIL).

•	The VCM commands third gear only.

•	The VCM inhibits TCC engagement.

•	The VCM commands maximum line pressure.

•	The VCM freezes shift adapts from being updated.

•	DTC P0756 stores in VCM history.

Conditions for Clearing the MIL/DTC

•	The VCM turns OFF the MIL after three consecutive trips without a failure reported.

•	A scan tool can clear the DTC from the VCM history. The VCM clears the DTC from the VCM history if the vehicle completes 40 warm-up cycles without a failure reported.

•	The VCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the VCM.

Diagnostic Aids

•	Verify that the transmission meets the specifications in the 4L60-E Shift Speed table.

•	Other internal transmission failures may cause more than one shift to occur.

•	Refer to the Shift Solenoid Valve State and Gear Ratio table.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

This step verifies that the scan tool commanded all shifts, that all shift solenoids responded correctly, but all the shifts did not occur.

DTC P0756 2-3 Shift Solenoid Valve -- Performance (4.3L)

Step

Action

Value(s)

Yes

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

Install the Scan Tool .
With the engine OFF, turn the ignition switch to the RUN position.

Record the DTC Freeze Frame and Failure Records, then clear the DTC(s).
Drive the vehicle in D4 range, under the following conditions:

Accelerate the vehicle, ensuring that the VCM commands 1st, 2nd, 3rd and 4th gears.

Did you detect a 1-2-2-1 or 4-3-3-4 shift pattern?

Go to Step 3

Go to Diagnostic Aids

Inspect the shift solenoid/hydraulic circuit for the following conditions:

•	An internal malfunction

•	Damaged seals on the shift solenoid valves.

Refer to Shift Solenoid Leak Test.

Did you find and correct the condition?

Go to Step 4

In order to verify your repair, perform the following procedure:

Select DTC.
Select Clear Info.
Drive the vehicle in D4 under the following conditions (only if traffic and road conditions permit):

•	Hold the throttle at 50% and accelerate to 64 km/h (40 mph).

•	Stop the vehicle, engine idling.

•	Hold the throttle at 25% and accelerate to 80 km/h (50 mph).

Select Specific DTC. Enter DTC P0756.

Has the test run and passed?

System OK

Go to Step 1