P0685
DTC P0685, P0686, P0687, P0689, or P0690
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
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/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 under-hood fuse block.
Conditions for Running the DTC
P0685, P0686, and P0687
* The ignition voltage is between 10-18 volts.
* The engine speed is greater than 80 RPM.
* The powertrain relay has been commanded ON and OFF.
* The DTCs run continuously once the above condition is met.
P0689 and P0690
* The ignition voltage is between 10-18 volts.
* The ignition is ON.
* The DTCs runs continuously once the above condition is met.
Conditions for Setting the DTC
P0685, P0686, and P0687
The commanded state of the driver and the actual state of the control circuit do not match for greater than 4 seconds or for a cumulative of 30 seconds.
P0689 and P0690
The ECM detects that powertrain relay feedback voltage is less than 6 volts for greater than 1 second, when the powertrain relay is commanded ON or OFF. The condition exists for 4 seconds, or for a cumulative of 30 seconds.
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.
Reference Information
Schematic Reference
Engine Controls Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON, the scan tool should be able to establish communication with the ECM.
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, open the hood to disable the Auto-Stop function.
2. Ignition ON, verify the scan tool hood position parameter displays Open.
• If the hood position does not display Open, refer to DTC P254F (P254F).
3. Ignition OFF, remove the powertrain relay.
4. Ignition ON, verify a test lamp illuminates between both of the following relay battery voltage circuit terminals and ground.
* Terminal 85
* Terminal 30
• If the test lamp does not illuminate, repair the relay battery voltage circuit for a short to ground or an open/high resistance.
5. Ignition OFF, connect a test lamp between the relay coil control circuit terminal 86 and B+.
6. Cycle the ignition ON and OFF. 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 the control circuit for a short to ground. If the circuit/connections test normal, replace the ECM.
• If the test lamp remains OFF all the time, test the control circuit for a short to voltage or an open/high resistance. 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.
7. Connect a 20 A fused jumper wire between the relay switch B+ circuit terminal 30 and the relay switch ignition voltage circuit terminal 87.
8. 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.
9. If all circuits/connections test normal, test or replace the powertrain relay.
Component Testing
1. Test for 70-110 ohm between terminals 85 and 86 of the powertrain relay.
• If not within the specified range, replace the powertrain relay.
2. Test for infinite resistance between the following terminals of the powertrain relay:
* 30 and 86
* 30 and 87
* 30 and 85
* 85 and 87
• If not the specified value, replace the relay.
3. Install a 20 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohm between terminals 30 and 87.
• If greater than the specified range, replace the powertrain relay.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))
* Control Module References (Programming and Relearning) for engine control module replacement, setup, and programming