Automatic Transmission - 2MT70

DTC P2534

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.

DTC Descriptor
DTC P2534
- Ignition 1 Switch Circuit Low 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. Lower than normal voltage may be inadequate to operate the transmission control solenoids properly. Improper solenoid operation may cause erratic transmission operation, which may result in internal damage.

Conditions for Running the DTC

The TCM is communicating on the GMLAN serial data bus.

Conditions for Setting the DTC

The TCM detects less than 2 volts on the IGN voltage circuit at the TCM for greater than 60 seconds in a 65 second window.

Action Taken When the DTC Sets

* DTC P2534 is a Type A DTC.
* The TCM turns OFF all solenoids.
* The TCM commands maximum line pressure.
* The TCM freezes transmission adaptive functions.

Conditions for Clearing the DTC

DTC P2534 is a Type A DTC.

Diagnostic Aids

Ensure the transmission connector and harness terminals are clean and not damaged, and the charging system is functioning correctly.

Reference Information
Schematic Reference

Automatic Transmission Controls Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)

Circuit/System Testing

1. Ignition OFF, disconnect the transmission 20-way in line harness connector at the transmission, verify that a test lamp does not illuminate between the ignition voltage circuit terminal 13 and ground.

• If the test lamp illuminates, test the IGN voltage circuit for a short to voltage.

2. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal 13 and ground.

• If the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance.
• If the circuit tests normal replace the control solenoid (w/body and TCM) valve assembly.

Repair Instructions

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

Control Module References (Programming and Relearning) for control solenoid (w/body and TCM) valve assembly replacement, setup, and programming.