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 provides an overview of each diagnostic category. |
DTC Descriptor
DTC P2534: Ignition 1 Switch Circuit Low VoltageCircuit/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 engine speed is greater than 500 RPM. |
| • | Ignition voltage is between 8.6-19.0 volts. |
Conditions for Setting the DTC
The TCM detects 2 volts or less on the ignition 1 voltage circuit at the TCM for 1.0 second or more.
Action Taken When the DTC Sets
| • | DTC P2534 is a Type A DTC. |
| • | The TCM turns OFF HSD1 and HSD2. |
| • | The TCM turns OFF all solenoids. |
| • | The TCM commands maximum line pressure. |
| • | The TCM freezes transmission adaptive functions. |
| • | The TCM commands the TCC OFF. |
| • | The TCM allows the vehicle to operate in transmission protection mode. |
| • | The TCM disables Tap up and Tap down functions. |
Conditions for Clearing the DTC
DTC P2534 is a Type A DTC.
Diagnostic Aids
| • | If all circuit tests are OK, ensure the transmission pass through connector and harness terminals are clean and not damaged, and the charging system is functioning correctly. |
| • | Verify there is a good connection at the body control module (BCM). |
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
Electrical Information Reference
Description and Operation
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
Clear the DTC and operate the vehicle under the conditions for running and setting the DTC.
| ⇒ | If the DTC resets, test the TCM ignition 1 voltage circuit for battery positive voltage at the TCM 16-way connector. |
| ⇒ | If the voltage is less than battery voltage, test the Ignition 1 voltage circuit for an open or short to ground and repair the circuit as necessary. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Perform the Service Fast Learn Adapts if internal transmission repairs are performed.
