M99 - Automatic Transmission
DTC P0961, P0962 or P0963
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
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 when the engine is running. The transmission control module (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 line PC solenoid is commanded ON or OFF.
DTC P0961
DTC P0961 is not failed this ignition.
DTC P0962
DTC P0962 is not failed this ignition.
DTC P0963
DTC P0963 is not failed this ignition.
Conditions for Setting the DTC
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 300 milliseconds.
DTC P0962
The TCM detects an internal low voltage electrical malfunction of the line PC solenoid control circuit for 300 milliseconds.
DTC 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
DTC P0961
* DTC P0961 is a Type B DTC.
* The TCM freezes transmission adaptive functions.
DTC P0962
* DTC P0962 is a Type A DTC.
* The TCM defaults the transmission to 3rd gear.
* The TCM commands maximum line pressure.
* The TCM freezes transmission adaptive functions.
DTC P0963
* DTC P0963 is a Type A DTC.
* The TCM freezes transmission adaptive functions.
Conditions for Clearing the DTC
* DTC P0961 is a Type B DTC.
* DTCs P0962 and P0963 are Type A DTCs.
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.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views
Electrical Information Reference
* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs
* High Voltage Disabling
* High Voltage Enabling
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
* Scan Tool Output Controls (Scan Tool Output Controls)
* Scan Tool Data List (Scan Tool Data List)
* Scan Tool Data Definitions (Scan Tool Data Definitions)
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 TCM Assembly Solenoid Performance Test) .
• 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.
Control solenoid (w/body and TCM) valve assembly replacement. Refer to Control Module References for replacement, setup, and programming.