GM Service Manual Online
For 1990-2009 cars only

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 P0615: Starter Relay Control Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

STRTR Relay Control

P0615

P0615

P0615

--

Ground

--

P0615

--

--

Circuit/System Description

When the ignition switch is placed in the start position, a discrete signal is supplied to the body control module (BCM) notifying it that the ignition is in the start position. The BCM sends a serial data message to the engine control module (ECM) that crank has been requested. The ECM then verifies that the automatic transmission is in Park or Neutral, and that the immobilizer is not disabling engine starting. If conditions are acceptable for cranking, then the ECM supplies 12 volts to the control circuit of the STRTR relay. When this occurs, battery voltage is supplied through the switch of the STRTR relay to terminal S X2 of the starter solenoid, and the engine cranks. The ECM monitors the voltage on the STRTR relay control circuit. If the ECM detects that the STRTR relay control circuit is open, shorted to ground, or shorted to voltage, then DTC P0615 sets.

Conditions for Running the DTC

    • The ignition is ON or in the start position.
    • The system voltage is between 9.5-18 volts.

Conditions for Setting the DTC

The ECM detects that the control circuit of the STRTR relay is open, shorted to ground, or shorted to voltage for 2 seconds.

Action Taken When the DTC Sets

DTC P0615 is a C type DTC.

Conditions for Clearing the DTC

The DTC passes when the ECM detects that the failure is no longer present for 2 seconds.

Diagnostic Aids

    • Verify that the ground connection for the STRTR relay ground circuit is clean and tight.
    • Inspect the terminals for the STRTR relay in the underhood fuse block for poor connections.

Reference Information

Schematic Reference

Starting and Charging Schematics

Connector End View Reference

Engine Electrical Connector End Views

Description and Operation

Starting System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

  1. Ignition ON, verify that no immobilizer or transmission DTCs are set that would cause the ECM to disable engine starting.
  2. If any DTCs are set that would cause the ECM to disable starting, then refer to Diagnostic Trouble Code (DTC) List - Vehicle .
  3. Clear the DTCs. Attempt to start the engine. The engine should crank and DTC P0615 should not set.

Circuit/System Testing

  1. Ignition OFF, disconnect the STRTR relay.
  2. Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 ohms between the relay ground circuit terminal 85 and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85. Turn the ignition to the start position. The test lamp should turn ON for no longer than 10 seconds when the ignition is in the START position, and OFF in all other positions.
  5. If the test lamp is always on, test the control circuit for short to voltage. If the circuit tests normal, replace the ECM.
    If the test lamp is always off, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  6. If all circuits test normal, test or replace the STRTR relay.

Component Testing

STRTR Relay

  1. Ignition OFF, disconnect the STRTR relay.
  2. Test for 60-180 ohms between terminals 85 and 86 of the relay.
  3. If not within the specified range, replace the STRTR relay.
  4. Test for infinite resistance between the following terminals:
  5. • 30 and 86
    • 30 and 87
    • 30 and 85
    • 85 and 87
    If not the specified value, replace the relay.
  6. Install a 20 amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87 of the relay.
  7. If greater than specified range, replace the relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Relay Replacement
    •  Control Module References for ECM replacement, setup, and programming.