2ML70 - Automatic Transmission

DTC P2534

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

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 serial data circuit.

Conditions for Setting the DTC

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

Action Taken When the DTC Sets

* 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

P2534 is a Type A DTC.

Diagnostic Aids

* Ensure the transmission pass through connector and harness terminals are clean and not damaged, and the charging system is functioning correctly.
* The transmission X176 24-way inline harness connector must be disconnected prior to disconnecting the transmission X1 16-way inline harness connector

Reference Information
Schematic Reference

Automatic Transmission Controls Schematics (2ML70 - Automatic Transmission)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
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 the X176 24-way harness connector at the transmission, then the X1 16-way harness connector at the transmission, verify that a test lamp does not illuminate between the ignition voltage circuit terminal 12 and ground.

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

2. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal 12 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 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.