GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Opel 🢒 2007 🢒 Antara 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC P068A, P068B, or P2510

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 P068A: Engine Controls Ignition Relay Control Circuit

DTC P068B: Engine Controls Ignition Relay Control Circuit

DTC P2510 58: Engine Controls Ignition Relay Control Circuit Incorrect Reaction After Event

DTC P2510 59: Engine Controls Ignition Relay Control Circuit/Component Protection Time-Out

Circuit/System Description

The Engine Controls Ignition Relay or Main Relay, is controlled by the engine control module (ECM) depending upon input from the ignition switch. Battery positive voltage is supplied to the relay coil and switch. When the ignition switch is turned to the ON position, the ECM will provide ground on the control circuit of the relay using a low side driver. This will allow voltage through the relay switch contacts to the components. The ECM monitors the voltage level on the control circuit of the relay.

Conditions for Running the DTC

DTC P068A and P2510 58

    • The ignition is ON, or the engine is operating.
    • The DTCs run continuously once the above condition is met.

DTC P068B and P2510 59

    • The ignition is switched OFF.
    • The DTC runs continuously until the ECM powers down.

Conditions for Setting the DTC

The ECM detects the Engine Controls Ignition Relay Control Circuit is open, shorted to ground, or shorted to voltage.

Action Taken When the DTC Sets

DTCs P068A, P068B, and P2510 are Type C DTCs.

Conditions for Clearing the DTC

DTCs P068A, P068B, and P2510 are Type C DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Engine Control Module Connector End Views
    •  Engine Controls 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

Scan Tool Reference

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

Circuit/System Verification

Important: If You were sent here from Engine Cranks But Does Not Run proceed to Circuit/System Testing.

  1. Ignition ON, observe the DTC information with a scan tool. DTCs P068A, P068B, or P2510 should not set.
  2. Cycle the ignition from OFF to ON. You should hear and feel an audible click from the Main ignition relay. Repeat as necessary in order to verify Main ignition relay operation.
  3. If the vehicle passes the Circuit/System Verification test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records List.

Circuit/System Testing
  1. Ignition OFF, disconnect the Main ignition relay.
  2. Ignition ON, verify that a test lamp illuminates between the coil voltage supply circuit terminal 85 and ground.
    3. ⇒If the test lamp does not illuminate, repair the coil voltage supply circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect a test lamp between the coil control circuit terminal 86 and the coil voltage supply circuit terminal 85. The test lamp should not be illuminated.
    4. ⇒If the test lamp remains ON all the time, test for a short to ground on the control circuit. If the circuit/connections test normal, replace the ECM.
  4. Ignition ON. The test lamp should turn ON.
    5. ⇒If the test lamp remains OFF all the time, test for a short to voltage or an open/high resistance on the control circuit. If circuit/connections test normal, replace the ECM.
  5. Connect a 20A fused jumper wire between the switch voltage supply circuit terminal 30 and the ignition 1 voltage circuit terminal 87.
  6. Attempt to start the engine. The engine should start.
    7. ⇒If the engine does not start, test the ignition 1 voltage circuit between the EC ignition relay and the ECM for a short to ground or for an open/high resistance. If the circuit/connections test normal, replace the ECM.
  7. If all circuits/connections test normal, test or replace the Main ignition relay.

Component Testing
  1. Measure for 70-110 ohms of resistance between terminals 85 and 86 of the Main ignition relay.
    2. ⇒If the resistance is not within the specified range, replace the Main ignition relay.
  2. Measure for infinite resistance between the following terminals of the Main ignition relay:
    3. • 30 and 86
    • 30 and 87
    • 30 and 85
    • 85 and 87
    ⇒If continuity is detected, replace the Main ignition relay.
  3. Connect a 10A fused jumper wire from B+ to relay terminal 85. Connect a jumper wire from ground to relay terminal 86. Measure for less than 2 ohms between terminals 30 and 87 of the relay.
    4. ⇒If the resistance measures greater than 2 ohms, replace the Main ignition relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming