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: Ignition Accessory Switch Circuit Low Voltage

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Ignition Voltage	P2537	--	--	P2534

Typical Scan Tool Data

Accessory Voltage

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
*Operating Conditions:* Key ON *Parameter Normal Range:* 8-18 volts
Accessory	0 volts	0 volts	B+

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Operating Conditions: Key ON

Parameter Normal Range: 8-18 volts

Accessory

0 volts

B+

Circuit/System Description

The transmission control module (TCM) samples the system voltage on the accessory voltage circuit every 0.1 seconds. Higher or lower than normal voltage may cause erratic transmission operation.

Conditions for Running the DTC

The transmission control module is communicating on the serial data circuits.

Conditions for Setting the DTC

The transmission control module detects less than 2 volts on the ignition voltage circuit at the transmission control module for greater than 10 seconds.

Action Taken When the DTC Sets

•	P2537 is a Type A DTC.

•	The transmission control module turns OFF all solenoids.

•	The transmission control module commands maximum line pressure.

•	The transmission control module freezes transmission adaptive functions.

Conditions for Clearing the DTC

P2537 is a Type A DTC.

Diagnostic Aids

•	Verify the Q8 control solenoid valve assembly X1 connector and harness terminals are clean and not damaged.

•	Verify the charging system is functioning correctly.

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Circuit/System Testing

Vehicle OFF, disconnect Q8 control solenoid assembly X1 connector.
Vehicle ON, test for 8-18V between the Q8 control solenoid valve assembly X1 connector ignition voltage circuit terminal 15 and ground.

⇒	If not within the specified range, test the accessory voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal replace the Q8 control solenoid valve assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Control Solenoid Valve Assembly and Transmission Control Module Assembly replacement, programming, and setup.