4L80-E/4L85-E - Automatic Transmission

DTC P2534

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 provide an overview of each diagnostic category.



DTC Descriptors
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 second. 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 transmission damage.


Conditions for Running the DTC

The engine is running.


Conditions for Setting the DTC

The TCM detects an open or short to ground on the ignition 1 voltage circuit.


Action Taken When the DTC Sets

DTC P2534 is a type A DTC.


Conditions for Clearing the DTC

DTC P2534 is a type A DTC.


Reference Information
Schematic Reference

Automatic Transmission Controls Schematics (6.6L) (Electrical Diagrams)Automatic Transmission Controls Schematics (4.8L and 6.0L) (Electrical Diagrams)
Connector End View Reference

Component Connector End Views
Description and Operation

Transmission General Description (Transmission General Description)
Electrical Information Reference

* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference

Control Module References for scan tool information
Special Tools

J 35616 GM Terminal Test Kit


Circuit/System Verification

Ignition ON, observe the Ignition 1 Signal parameter with the scan tool. The Ignition 1 Signal parameter should read between 12.0-14.5-volts.


Circuit/System Testing

1. Measure the voltage at the battery terminals and compare it with the Ignition 1 Signal parameter on the scan tool. Verify that battery and Ignition 1 signal readings do not differ greater than 1.0-volt.

• --> If greater than 1.0-volt, test the Ignition 1 and ground circuits of the TCM for high resistance. If the circuits test normal, replace the TCM.

2. Refer to Charging System Test .



Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.


Control Module References for TCM replacement, setup, and programming.