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 Instructionsprovides 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 Programming and Relearningfor Control Solenoid Valve Assembly replacement, programming and setup.