4ET50 - Automatic Transmission

DTC P2534 or P2535

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 Descriptor
DTC P2534
- Ignition 1 Switch Circuit Low Voltage

DTC P2535
- Ignition 1 Switch Circuit High Voltage

Diagnostic Fault Information






Typical Scan Tool Data






Circuit/System Description

The transmission control module (TCM) samples the system voltage on the Ignition 1 voltage circuit every 0.1 seconds. higher or lower than normal voltage may cause erratic transmission operation.

Conditions for Running the DTC

The transmission control module is communicating on the GMLAN serial data bus.

Conditions for Setting the DTC

The transmission control module detects less than 2 volts on the ignition voltage circuit at the transmission control module for greater than 10 seconds.

Action Taken When the DTC Sets

* DTCs P2534 and P2535 are Type A DTCs.
* The transmission control module turns OFF all solenoids.
* The transmission control module commands maximum line pressure.
* The transmission control module freezes transmission adaptive functions.

Conditions for Clearing the DTC

DTCs P2534 and P2535 are Type A DTCs.

Diagnostic Aids

* Verify the control solenoid valve assembly X1 connector and harness terminals are clean and not damaged.
* Verify the charging system is functioning correctly.

Reference Information
Schematic Reference

Automatic Transmission Controls Schematics Electrical Diagrams
Connector End View Reference

Component Connector End Views Hybrid/EV Battery Pack X1 A4
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

Circuit/System Testing

1. Ignition OFF, disconnect control solenoid valve assembly X1 connector.
2. Ignition ON, test for 8-18V between the Q8 control solenoid valve assembly X1 connector ignition voltage circuit terminal 12 and ground.

• If not within the specified range, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal replace the Q8 control solenoid valve assembly.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

Control Module References Control Module References for Control Solenoid Valve Assembly replacement, programming, and setup.