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 VoltageDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Ignition 1 Voltage | P2534 | P2534 | -- | P0562, P0563 |
Typical Scan Tool Data
Circuit | Normal | Short to Ground | Open/High Resistance | Short to Voltage |
|---|---|---|---|---|
Operating Conditions: Engine running in Park, normal operating temperature Parameter Normal Range: 12.0-14.5 volts | ||||
Ignition Voltage | 12.0-14.5 volts | 0 volts | 0 volts | 12.0-14.5 volts |
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 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. |
| • | The TCM commands maximum line pressure. |
| • | The TCM commands an immediate landing to 2nd gear. |
| • | The TCM freezes transmission adaptive functions. |
Conditions for Clearing the DTC
DTC P2534 is a Type A DTC.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
Special Tools
| • | J 35616 GM terminal test kit |
| • | J 44152 Jumper Harness (20 pins) |
Circuit/System Verification
Start and idle the engine. Using the scan tool, select the Ignition Voltage parameter on the scan tool. The Ignition Voltage parameter should be between 12-14.5 volts.
Circuit/System Testing
- Remove the TRANS fuse. Inspect the fuse for an open.
- Disconnect the TCM connector. Turn ON the ignition leaving the engine OFF. Using the J 35616 GM Terminal Test Kit, measure the voltage at the ignition 1 voltage circuit. The voltage should be near battery voltage.
| ⇒ | If the fuse is open, test the ignition 1 voltage circuit for a short to ground. |
| ⇒ | If the voltage is below the specified value, test the ignition 1 voltage circuit for an open or high resistance. |
| ⇒ | If all circuits and connections test normal, replace the TCM. |
Component Testing
Verify that there is near battery voltage on the ignition 1 voltage circuit at the TCM.
| ⇒ | If the voltage is not near the specified value, repair the short to ground, open or high resistance in the ignition 1 voltage circuit. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for TCM replacement, setup, and programming.
