Automatic Transmission - 6T40/6T45
DTC P2534
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) 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 speed is greater than 500 RPM for 5 seconds.
* Ignition voltage is between 9.0 volts and 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 6 seconds or more.
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 vehicle to operate in transmission protection mode.
* The TCM inhibits TU TD/MUMD operation.
Conditions for Clearing the DTC
DTC P2534 is a Type A DTC.
Diagnostic Aids
* Observe the driver information center (DIC) messaging that would indicate the electrical system requires service.
* Inspect for the following conditions:
- Loose or damaged terminals at the generator
- Loose or worn generator drive belt
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
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 (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
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 12.6-15.0 volts.
• If not within the specified range, refer to Charging System Test (Charging System Test).
2. Observe the scan tool TCM Ignition Voltage parameter. The reading should be between 12.6-15.0 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 10 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 ignition circuit terminals listed below and ground.
* Terminal 1
* Terminal 12
* Terminal 13
• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
5. If all circuits test normal, replace the control solenoid (w/body and TCM) valve assembly.
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 (Programming and Relearning) following all transmission related repairs.