Wiring Systems and Power Management
DTC P2537
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 P2537
- Ignition Accessory Switch Circuit Low Voltage
Diagnostic Fault Information
Circuit/System Description
The transmission control module (TCM) continuously monitors the voltage on the Ignition Accessory/Run circuit from the body control module (BCM). When the ignition switch is in the ACCESSORY or RUN position, the BCM sends a 12 V wake up signal to the TCM. This wake up signal allows the TCM to power up and start functioning before the engine is started.
Conditions for Running the DTC
The ignition switch is in the Accessory or Run position.
Conditions for Setting the DTC
The TCM detects the Ignition Accessory/Run circuit is less than 6 V for 1 min.
Action Taken When the DTC Sets
DTC P2537 is a Type C DTC.
Conditions for Clearing the DTC
DTC P2537 is a Type C DTC.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics 6T40 (MH8,MHH) - Automatic Transmission
Connector End View Reference
* Component Connector End Views Sunshade - Left
* Inline Harness Connector End Views X110
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 Control Module References for scan tool information
Special Tools
DT 48616-10 - Jumper Harness
For equivalent regional tools, refer to Special Tools 6T40 (MH8,MHH) - Automatic Transmission.
Circuit/System Verification
1. Ignition in the ACCESSORY position.
2. Verify the scan tool BCM Accessory Relay Command parameter is Active.
• If the parameter is not Active
Refer to Power Mode Mismatch Power Mode Mismatch.
• If the parameter is Active
3. Ignition ON.
4. Verify the scan tool BCM Accessory Relay Command parameter is Active.
• If the parameter is not Active
Refer to Power Mode Mismatch Power Mode Mismatch.
• If the parameter is Active
5. Ignition ON, clear all DTCs in the K9 Body Control Module and the Transmission Control Module, ignition OFF for 2 min.
6. Engine Running for 1 min with the transmission in Park.
7. Verify DTC P2537 is not set in the K71 Transmission Control Module.
• If DTC P2537 is set
Refer to Circuit/System Testing.
• If DTC P2537 is not set
8. After performing the above steps, verify that the DTC does not set by operating the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions you observe from the Freeze Frame/Failure Records data. If the vehicle passes the Circuit/System Verification procedure, then STOP. Do not perform the Circuit/System Testing or Component Testing as this may result in an unnecessary part replacement. Refer to Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the T12 Automatic Transmission Assembly. Install the DT 48616-10 - jumper harness to the X1 vehicle wire harness connector.
2. Ignition ON.
3. Verify a test lamp illuminates between the ignition circuit terminal 13 and ground.
• If the test lamp does not illuminate.
1. Ignition OFF remove the test lamp, disconnect the X4 connector at the K9 Body Control Module.
2. Test for infinite resistance between the ignition circuit and ground.
• If less than infinite resistance, repair the short to ground in the circuit.
• If infinite resistance
3. Test for less than 2 ohms on the ignition circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K9 Body Control Module.
• If the test lamp illuminates
4. Replace the K71 Transmission Control Module.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
Refer to Control Module References Control Module References for body control module or transmission control module replacement, programming, and setup.