6T30/6T40/6T45 - 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
Circuit/System Description
The transmission control module (TCM) continuously monitors the system voltage on the Ignition 1 voltage circuit. 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 control module (ECM) communicates that the engine is running through the controller area network (CAN).
Conditions for Setting the DTC
The TCM detects 6 volts or less on the ignition 1 voltage circuit at the TCM for 7 seconds or greater.
Action Taken When the DTC Sets
* DTC P2534 is a type A DTC.
* The TCM turns OFF all high side drivers.
* 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 transmission to operate in reverse and fifth range.
* The TCM inhibits Tap Up/Tap Down operation.
* The TCM inhibits manual up, manual down shifts with the shift selector.
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.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (6T30/6T40/6T45 - Automatic Transmission)
Connector End View Reference
* Component Connector End Views (Connector End Views By Name)
* Inline Harness Connector End Views (Connector End Views By Number)
Description and Operation
* Transmission General Description (Transmission General Description)
* Transmission Component and System Description (Transmission Component and System Description)
* Electronic Component Description (Electronic Component Description)
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)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Special Tools
DT-48616-10 Adapter Harness
Circuit/System Verification
1. Engine ON, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.4-14.5 volts.
• If the voltage is not within the specified range, or the charge indicator light is on, refer to Charging System Test (Charging System Test).
2. Observe the scan tool TCM Ignition Voltage parameter. The reading should be between 12.4-14.5 volts.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, disconnect the 14-way harness connector at the transmission.
2. Connect the DT-48616-10 to the 14-way transmission harness connector.
3. Test for less than 5 ohms between the ground circuit terminal 2 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
4. Ignition ON, verify that a test lamp illuminates between the B+ and ignition circuit terminals listed below and ground.
* Terminal 1
* Terminal 12
* Terminal 13
• If the test lamp does not illuminate, test the affected B+ or ignition circuit for a short to ground or an open/high resistance.
5. If all circuits test normal, replace the control solenoid valve assembly. Refer to Control Solenoid Valve and Transmission Control Module Assembly Replacement (Service and Repair).
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
Important: Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection (Control Solenoid Valve and Transmission Control Module Assembly Inspection).
* Refer to Control Module References (Programming and Relearning) for control solenoid (w/body and TCM) valve assembly replacement, setup, and programming.
* Perform the Service Fast Learn Adapts (6T30/6T40/6T45 - Automatic Transmission) following all transmission related repairs.