DTC P0753 1-2 Shift Solenoid Circuit Electrical. GMC Truck Savana 1999

Go to Step 4

Using the transmission output control function on the scan tool, command the 1-2 SS valve ON and OFF three times while listening to the bottom of the transmission pan (use a stethoscope if needed).

Does the solenoid click when commanded?

Go to Diagnostic Aids

Go to Step 5

Turn the ignition OFF.
Disconnect the transmission 20-way connector (additional DTCs will set).
Install the J 39775 jumper harness on the engine harness connector.
With the engine OFF, turn the ignition switch to the RUN position.
Connect a 12 volt test lamp from the J 39775 cavity E to ground.

Is the test lamp on?

Go to Step 7

Go to Step 6

Repair the open or high resistance in ignition feed circuit 1020 (PNK) to the 1-2 SS valve.

Refer to Wiring Repairs in Wiring Systems.

Was the condition corrected?

Install a 12 volt test lamp between cavities E and A of the J 39775 .
Using the transmission output control function, command the 1-2 SS valve ON and OFF three times.

Does the test lamp illuminate when the shift solenoid is commanded ON and turn off when the shift solenoid is commanded OFF?

Go to Step 10

Go to Step 8

Inspect circuit 1222 (LT GRN) for an open or short to ground.

Refer to General Electrical Diagnosis in Wiring Systems.

Was the condition found?

Go to Step 9

Replace the VCM.

Refer to VCM Replacement/Programming (4.3L) or VCM Replacement/Programming (5.7L) or VCM Replacement/Programming (7.4L) in Engine Controls.

Is the replacement complete?

Turn the ignition OFF.
Install J 39775 on the transmission 20-way connector (Automatic Transmission Connector End View).
With the J 39200 digital multimeter (DMM) and the J 35616 connector test adapter kit , measure the resistance between terminals A and E.

Is the resistance within the specified values?

19-31ohms

Go to Step 12

Go to Step 11

Disconnect the automatic transmission wiring harness assembly from the 1-2 SS valve.
Measure the resistance of the 1-2 SS valve.

Is the resistance within the specified values?

19-31ohms

Measure the resistance between terminal A and ground. Use the J 39200 DMM.
Measure the resistance between terminal E and ground.

Are both readings greater than the specified value?

250kohms

Go to Diagnostic Aids

Go to Step 13

Disconnect the automatic transmission wiring harness assembly from the 1-2 SS valve.
Measure the resistance from the component's terminals to ground.

Are both readings greater than the specified value?

250kohms

Replace the automatic transmission wiring harness assembly.

Refer to Internal Wiring Harness Replacement.

Is the replacement complete?

Replace the 1-2 SS valve.

Refer to Control Valve Body Removal and Disassembly.

Is the replacement complete?

Repair the circuit as necessary.

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 17

Perform the following procedure in order to verify the repair:

Select DTC.
Select Clear Info.
Select the parameters 1-2 Solenoid and 1-2 Solenoid Open/Shorted to GND, and 1-2 Solenoid Shorted to Volts.
Operate the vehicle under the following conditions:

•	The VCM commands the 1-2 SS valve ON, and the 1-2 Solenoid Shorted to Voltage is NO.

•	The VCM commands the 1-2 SS valve OFF, and the 1-2 Solenoid Open/Shorted to GND is NO.

•	All conditions met for 5 seconds.

Select Specific DTC.
Enter DTC P0753.

Has the test run and passed?

System OK

Go to Step 1

DTC P0753 1-2 Shift Solenoid Circuit Electrical Diesel

Automatic Transmission Components Diesel
Automatic Transmission Controls Schematics Diesel
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The 1-2 shift solenoid (1-2 SS) valve controls the fluid flow acting on the 1-2 and the 3-4 shift valves. The 1-2 SS valve is a normally-open exhaust valve that is used with the 2-3 shift solenoid (2-3 SS) valve in order to allow four different shifting combinations. The 1-2 SS valve attaches to the control valve body within the transmission. The ignition voltage goes directly to the 1-2 SS valve. The powertrain control module (PCM) controls the 1-2 SS valve by providing the ground path through circuit 1222.

If the PCM detects a continuous open or short to ground in the 1-2 SS valve circuit or the 1-2 SS valve, then DTC P0753 sets. DTC P0753 is a type A DTC.

Conditions for Running the DTC

•	The engine runs more than 475 RPM for greater than 7 seconds.

•	System voltage is 8.0-18.0 volts.

Conditions for Setting the DTC

The above conditions are met and either of the following conditions occur for 4.3 out of 5 seconds:

•	The PCM commands the Solenoid ON and the voltage input remains high (B+).

•	The PCM commands the Solenoid OFF and the voltage input remains low (0 volts).

Action Taken When the DTC Sets

•	The PCM illuminates the malfunction indicator lamp (MIL).

•	The PCM commands maximum line pressure.

•	The PCM freezes shift adapts.

•	The PCM stores DTC P0753 in PCM history.

Conditions for Clearing the MIL/DTC

•	For Federal and California emissions, the PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.

•	A scan tool clears the DTC from PCM history.

•	For Federal and California emissions, the PCM clears the DTC from PCM history if the vehicle completes 40 consecutive warm-up cycles without an emission related diagnostic fault occurring.

•	For vehicles equal to or greater than 15,000 lbs GVW, the PCM clears the DTC from PCM history if the vehicle completes 40 consecutive warm-up cycles without a non-emission related diagnostic fault occurring.

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

Diagnostic Aids

•	Inspect the wiring at the PCM, the transmission connector and all other connecting points for the following conditions:

-	A backed out terminal

-	A damaged terminal

-	Reduced terminal tension

-	A chafed wire

-	A broken wire inside the insulation

-	Moisture intrusion

Corrosion

•	When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.

•	An open ignition feed circuit can cause multiple DTCs to set.

•	First diagnose and clear any engine DTCs that are present. Then inspect for any transmission DTCs that may have reset.

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

Test Description

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

This step tests the function of the 1-2 SS valve and the automatic transmission wiring harness assembly.

This step tests the power to the 1-2 SS valve from the ignition through the fuse.

This step tests the ability of the PCM and the wiring to control the ground circuit.

This step measures the resistance of the automatic transmission wiring harness assembly and the 1-2 SS valve.

P0753

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 Freeze Frame and Failure Records.
Clear the DTC.

Are DTCs P0758 or P1860 also set?

Go to Step 3

Go to Step 4

Inspect the transmission fuse for an open.
If an open fuse is found, inspect circuit 1020 (PNK), the three solenoids, and the automatic transmission wiring harness assembly for a short to ground.

Refer to General Electrical Diagnosis in Wiring Systems.

Was the condition found?

Go to Step 5

Using the transmission output control function on the scan tool, command the 1-2 SS valve ON and OFF three times while listening to the bottom of the transmission pan (use a stethoscope if needed).

Does the solenoid click when commanded?

Go to Diagnostic Aids

Go to Step 5

Turn the ignition OFF.
Disconnect the transmission 20-way connector (additional DTCs will set).
Install the J 39775 jumper harness on the engine side of the 20-way connector.
With the engine OFF, turn the ignition switch to the RUN position.
Connect a test lamp from the J 39775 cavity E to a good ground.

Does the test lamp illuminate?

Go to Step 7

Go to Step 6

Repair the open or short to ground in ignition feed circuit 1020 (PNK) to the 1-2 SS valve.

Refer to Wiring Repairs in Wiring Systems.

Was the condition found?

Install a test lamp between cavity E and cavity A of the J 39775 .
Using the transmission output control function on the scan tool, command the 1-2 SS valve ON and OFF three times.

Does the test lamp illuminate when the shift solenoid is commanded ON and turn off when the shift solenoid is commanded OFF?

Go to Step 10

Go to Step 8

Inspect circuit 1222 (LT GRN) for an open or short to ground.

Refer to General Electrical Diagnosis in Wiring Systems.

Was the condition found?

Go to Step 9

Replace the PCM.

Refer to Powertrain Control Module Replacement/Programming in Engine Controls.

Is the replacement complete?

Turn the ignition OFF.
Install J 39775 on the transmission 20-way connector.
With the J 39200 digital multimeter (DMM) and the J 35616 connector test adapter kit, measure the resistance between terminals A and E.

Is the resistance within the specified value?

19-31ohms

Go to Step 12

Go to Step 11

Disconnect the automatic transmission wiring harness assembly from the 1-2 SS valve.
measure the resistance of the 1-2 SS valve.

Is the resistance within the specified values?

19-31ohms

Measure the resistance between terminals A and E and a good ground.

Are both reading greater than the specified value?

250kohms

Go to Diagnostic Aids

Go to Step 13

Disconnect the automatic transmission wiring harness assembly from the 1-2 SS valve.
Measure the resistance from the 1-2 SS valve terminals to a good ground.

Are both readings greater than the specified value?

250kohms

Replace the automatic transmission wiring harness assembly.

Refer to Automatic Transmission Wiring Harness Replacement.

Is the replacement complete?

Replace the 1-2 SS valve.

Refer to Control Valve Body Replacement.

Is the replacement complete?