6L50/6L80/6L90 - Automatic Transmission
DTC P0961-P0963
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (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 valve assembly which has no serviceable parts. The normally high line PC solenoid regulates and directs the PC solenoid oil pressure to the isolator/pressure regulator valve. Increasing PC solenoid line pressure increases transmission line pressure. The TCM varies the current to the line PC solenoid through a low side driver. Decreasing the current to the line PC solenoid increases line PC solenoid oil pressure by closing OFF the solenoid exhaust port. Increasing the current to the line PC solenoid decreases line PC oil pressure by opening the solenoid exhaust port. Line PC solenoid power is supplied by the TCM through a high side driver (HSD). The HSD protects the circuit and components from excessive current flow. If excessive current flow is detected, the HSD will turn OFF. When the fault is corrected the HSD will reset.
Conditions for Running the DTC
P0961, P0962, or P0963
* The engine speed is greater than 500 RPM for 5 seconds.
* The ignition voltage is 8.6 volts or greater.
* DTCs P0961, P0962 or P0963 are not set.
Conditions for Setting the DTC
P0961
The TCM detects an internal electrical malfunction of the line PC solenoid where the measured line PC solenoid current does not equal the commanded line PC solenoid current for 5 seconds.
P0962
The TCM detects a short to ground or an open/high resistance on the line PC solenoid control circuit for 1 second.
P0963
The TCM detects a short to voltage on the line PC solenoid control circuit for 1 second.
Action Taken When the DTC Sets
P0961
* DTC P0961 is a Type A DTC.
* The TCM freezes transmission adaptive functions.
P0962
* DTC P0962 is a Type A DTC.
* The TCM turns the high side driver OFF.
* The TCM defaults the transmission to 3rd gear if the current gear is 1st, 2nd, or 3rd, or 5th gear if the current gear is 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.
P0963
* DTC P0963 is a Type C DTC.
* The TCM freezes transmission adaptive functions.
* The TCM commands maximum line pressure.
Conditions for Clearing the DIC/DTC
* DTCs P0961 and P0963 are Type C DTCs.
* DTC P0962 is a Type A DTC.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (6L45/6L50/6L80/6L90 - Automatic Transmission)
Connector End View Reference
* Component Connector End Views (Connector End Views By Name)
* Inline Harness Connector End Views (Connector End Views By Number)
Description and Operation
* Transmission General Description (Transmission General Description)
* Transmission Component and System Description (Transmission Component and System Description)
* Electronic Component Description (Electronic Component Description)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Special Tools
DT-47825-10 - Jumper Harness
Circuit/System Verification
1. Engine running in Park position. Move the gear shifter lever into each gear position and back into Park position. Verify with a scan tool the following test status parameters display OK:
* Line Pressure Control Solenoid Performance Test Status
* Line Pressure Control Solenoid Control Circuit High Voltage Test Status
* Line Pressure Control Solenoid Control Circuit Low Voltage Test Status
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Note: You must perform the Circuit/System Verification first.
1. Ignition OFF, remove the Q8 control solenoid valve assembly. Refer to Control Solenoid Valve and Transmission Control Module Assembly Replacement (6L45/6L50/6L80/6L90 - Automatic Transmission).
2. Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection (Control Solenoid Valve and Transmission Control Module Assembly Inspection).
3. Place the Q8 control solenoid valve assembly on a clean work surface near the transmission assembly.
4. Connect DT-47825-10 - jumper harness between the vehicle wire harness electrical connector, and the Q8 control solenoid valve assembly electrical connector.
5. Ignition ON, verify with a scan tool the following test status parameters display OK:
* Line Pressure Control Solenoid Performance Test Status
* Line Pressure Control Solenoid Control Circuit High Voltage Test Status
* Line Pressure Control Solenoid Control Circuit Low Voltage Test
• If any test status parameter displays Fault or Malfunction, replace the Q8 control solenoid valve assembly.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Control solenoid valve assembly replacement. Refer to Control Module References (Programming and Relearning) for replacement, setup, and programming.
* Perform the Service Fast Learn Adapts (Programming and Relearning) following all transmission related repairs.