6T70/6T75 - Automatic Transmission
DTC P0961, P0962 or P0963
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC P0961
- Line Pressure Control (PC) Solenoid System Performance
DTC P0962
- Line Pressure Control (PC) Solenoid Control Circuit Low Voltage
DTC P0963
- Line Pressure Control (PC) Solenoid Control Circuit High Voltage
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The line pressure control (PC) solenoid is part of the control solenoid (w/body and TCM) valve assembly and is not serviced separately. The line PC solenoid regulates the transmission fluid line pressure. The TCM varies the current to the normally high line PC solenoid valve from 0.1 amp for maximum line pressure, to 1.1 amps for minimum line pressure. This is accomplished by varying the desired line pressure in kPa (psi).
Conditions for Running the DTC
* The engine run time is greater than 5 seconds.
* The ignition voltage is between 8.6 volts and 19.0 volts.
* The line PC solenoid is commanded ON.
P0961
DTC P0961 has not failed this ignition cycle.
P0962
DTC P0962 has not failed this ignition cycle.
P0963
DTC P0963 has not failed this ignition cycle.
Conditions for Setting the DTC
P0961
The TCM detects an internal electrical performance malfunction of the line PC solenoid control circuit and the actual line pressure does not equal the commanded line pressure for 4.4 seconds.
P0962
The TCM detects an internal low voltage electrical malfunction of the line PC solenoid control circuit for 300 milliseconds.
P0963
The TCM detects an internal high voltage electrical malfunction of the line PC solenoid control circuit for 300 milliseconds.
Action Taken When the DTC Sets
P0961, P0963
* DTCs P0961 and P0963 are Type C DTCs.
* The TCM freezes transmission adaptive functions.
P0962
* DTC P0962 is a Type A DTC.
* The TCM defaults the transmission to 3rd gear if the current gear is 1st, 2nd, or 3rd, or 5th gear if the current gear if 4th, 5th, or 6th gear.
* The TCM inhibits the torque converter clutch (TCC).
* The TCM commands maximum line pressure.
* The TCM freezes transmission adaptive functions.
Conditions for Clearing the DIC/DTC
* DTCs P0961 and P0963 are Type C DTCs.
* DTC P0962 is a Type A DTC.
Diagnostic Aids
When attempting to set solenoid electrical DTCs, ensure the TCM is warmed up and the transmission is operated in 2nd gear long enough to ensure a 3°C (5°F) increase in TCM substrate temperature. This will place the TCM under the optimal conditions to test solenoid electrical DTCs.
Circuit/System Testing
1. Ensure the transmission fluid temperature is between 50-80°C (122-176°F).
2. Operate the vehicle in 2nd gear long enough to ensure at least a 3°C (5°F) rise in TCM temperature, then operate the vehicle in Park for 5 seconds.
3. Observe the scan tool data parameter Line PC Sol. CKT Status, the parameter should display OK.
* If the parameter displays Open, Short to Volts, Short to GND or if the DTC resets, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection. Control Solenoid Valve and Transmission Control Module Assembly Inspection
* If no concerns are found during the inspection, replace the control solenoid (w/body and TCM) valve assembly.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
1. Control solenoid (w/body and TCM) valve assembly replacement - refer to programming and relearning for replacement, setup, and programming.
2. Perform the Service Fast Learn Adapts. Programming and Relearning