Diagnostic Instructions

DTC Descriptors

DTC P0685: Engine Controls Ignition Relay Control Circuit

DTC P0686: Engine Controls Ignition Relay Control Circuit Low Voltage

DTC P0687: Engine Controls Ignition Relay Control Circuit High Voltage

DTC P0689: Engine Controls Ignition Relay Feedback Circuit Low Voltage

DTC P0690: Engine Controls Ignition Relay Feedback Circuit High Voltage

Diagnostic Fault Information

Circuit	Short to Ground	High Resistance	Open	Short to Voltage	Signal Performance
B+ Supply Voltage - Coil	P0685	P0685	P0685	--	--
B+ Supply Voltage - Switch	--	P0689	P0689	P0690	--
Relay Control Circuit	P0686	P0685	P0685	P0687	P0685
Ignition Voltage Circuit	--	P0689	P0689	P0690	--

Circuit/System Description

The engine controls (EC) ignition relay, or powertrain relay is a normally open relay. The relay switch is held in the open position by spring tension. Battery positive voltage is supplied directly to the relay coil and the switch contact at all times. The engine control module (ECM) supplies the ground path to the relay coil control circuit via an internal integrated circuit called an output driver. When the ECM commands the powertrain relay ON, ignition voltage is supplied to several fuses in the underhood fuse block.

The fuse that provides power to terminal 3, 5, or 6 of ECM connector X2 feeds the internal ECM circuits associated with the throttle actuator control (TAC) operation.

Conditions for Running the DTC

P0685, P0686, and P0687

P0689 and P0690

Conditions for Setting the DTC

P0685, P0686, and P0687

The commanded state of the ODM and the actual state of the control circuit do not match.

P0689 and P0690

The ECM detects that powertrain relay feedback voltage is less than 6 volts for greater than 500 mS.

Action Taken When the DTC Sets

DTCs P0685, P0686, P0687, P0689, and P0690 are Type C DTCs.

Conditions for Clearing the MIL/DTC

DTCs P0685, P0686, P0687, P0689, and P0690 are Type C DTCs.

Diagnostic Aids

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 35616 Connector Test Adapter Kit

Circuit/System Verification

1. Ignition ON, you should be able to communicate with the ECM using a scan tool.
2. Ignition ON, view the DTC information with a scan tool. DTC P0685, P0686, P0687, P0689, or P0690 should not set.
3. 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

1. Ignition OFF, disconnect the powertrain relay.
2. Ignition ON, load test for B+ between the ignition supply circuit terminal 85 and ground.

⇒	If less than the specified range, test the ignition supply circuit for an open/high resistance.

3. Ignition ON, load test for B+ between the ignition supply circuit terminal 30 and ground.

⇒	If less than the specified range, test the ignition voltage circuit for an open/high resistance.

4. Ignition OFF, connect a test lamp between the control circuit terminal 86 of the powertrain relay and the B+ supply circuit terminal 85, coil side of the powertrain relay.
5. Turn ON the ignition. The test lamp should turn ON when the ignition switch is cycled ON and OFF when the ignition switch is cycled OFF.

⇒	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.

⇒	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.

Note: The ignition voltage circuit is between the powertrain relay and the ECM. The ignition voltage is a feedback circuit.

6. Connect a 15 A fused jumper wire between the B+ supply circuit terminal 30 and the ignition voltage circuit terminal 87 of the powertrain relay.
7. Attempt to start the engine. The engine should start.

⇒	If the engine does not start, test the ignition voltage circuit between the powertrain relay and the ECM for a short to ground or for an open/high resistance. If the circuit/connections test normal, replace the ECM.

8. Ignition ON, test for less than 1 V between the ignition voltage circuit terminal 87 of the powertrain relay and ground.

⇒	If greater than the specified value, repair the short to voltage in the ignition voltage circuit.

9. If all circuits/connections test normal, test or replace the powertrain relay.

Component Testing

1. Measure for 200-250 Ω between terminals 85 and 86 of the powertrain relay.

⇒	If not within the specified range, replace the powertrain relay.

2. Measure the resistance between the following terminals of the powertrain relay, the DMM should display OL:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If less than the specified value, replace the powertrain relay.

3. Connect a 15 A fused jumper wire from the positive terminal of the battery to relay terminal 85. Connect a jumper wire from the negative terminal of the battery to relay terminal 86. Test for less than 2 Ω between terminals 30 and 87 of the relay.

⇒	If greater than the specified range, replace the powertrain relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.