Service Information

Volt

DTC P2537

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 P2537: Accessory Wakeup Serial Data 2

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Accessory Wakeup Serial Data 2	C0561, P0335, P0700, P0AC4, P1E00, P2537, U0100, U1818, U1861	C0561, P0335, P0700, P0AC4, P1E00, P2537, U0100, U1818, U1861	P0AC4, P1E00	-

The hybrid powertrain control module 2 supplies 12 V to the Accessory Wakeup Serial Data 2 circuit as a wakeup signal to the control modules listed below. This occurs when the body control module (BCM) signals the engine control module (ECM) that serial data is required.

•	G1 A/C Compressor

•	K1 14 V Power Module

•	K16 Battery Energy Control Module (BECM)

•	K17 Electronic Brake Control Module (EBCM)

•	K20 Engine Control Module

•	T6 Power Inverter Module

•	T12 Transmission Control Module (TCM)

•	T18 Battery Charger Control Module

Conditions for Running the DTC

•	The propulsion system is active for greater than 0.5 s.

•	The DTC runs once per ignition cycle when the above condition is met.

Conditions for Setting the DTC

The ECM detects that the state of the accessory line is low when it should be high.

Action Taken When the DTC Sets

DTC P2537 is a type B DTC.

Conditions for Clearing the DTC

DTC P2537 is a type B DTC.

Diagnostic Aids

A short to ground or an open/high resistance on the Accessory Wakeup Serial Data 2 circuit may set multiple no communication codes for high speed GMLAN control modules.

Reference Information

Schematic Reference

•	Data Communication Schematics

•	Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

•	Hybrid Modes of Operation Description

•	Data Link Communications Description and Operation

Electrical Information Reference

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Vehicle in Service Mode, observe the DTC information with a scan tool. DTC UXXXX should not be set.

⇒	If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.

Observe the DTC information with a scan tool. DTC P2537 should not be set.
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

Vehicle OFF, disconnect the X2 harness connector at the K114B hybrid powertrain control module 2.
Vehicle in Service Mode, verify that a test lamp does not illuminate between the accessory wakeup serial data 2 circuit terminal 69 X2 of the harness connector and B+.

⇒	If the test lamp illuminates, repair the circuit for a short to ground.

Connect a 3 A fused jumper wire between the accessory wakeup serial data 2 circuit terminal 69 X2 of the harness connector and B+. The scan tool Ignition Accessory Signal parameter should display ON.

⇒	If the parameter does not display ON, repair the accessory wakeup serial data 2 circuit for an open/high resistance.

If all circuits test normal, replace the K20 ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for control module replacement, programming and setup