P0689
DTC P0685, P0689, or P0690
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructionsprovides an overview of each diagnostic category.
DTC Descriptors
DTC P0685
- Engine Controls Ignition Relay Control Circuit
DTC P0689
- Engine Controls Relay Feedback Circuit Low Voltage
DTC P0690
- Engine Controls Relay Feedback Circuit High Voltage
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The powertrain relay is a normally open relay. The relay armature is held in the open position by spring tension. Battery positive voltage is supplied directly to the relay coil and the armature 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 module (ODM). The ODM output control is configured to operate as a low side driver for the powertrain relay. The ODM for the powertrain relay also incorporates a fault detection circuit, which is continuously monitored by the ECM. When the ECM commands the powertrain relay ON, ignition 1 voltage is supplied to the ECM, and to several additional circuits.
Conditions for Running the DTC
P0685
* The ignition is ON.
* The battery voltage is between 9-16 V.
P0689
* The ignition is ON.
* The powertrain relay is commanded ON.
* DTC P0685 is not set.
P0690
* This DTC will run with the ignition ON or OFF.
* This DTC will run when the powertrain relay is commanded ON or OFF.
* DTC P0685 is not set.
Conditions for Setting the DTC
P0685
* The commanded state of the ODM and the actual state of the control circuit do not match.
* The condition is present for more than 5 s.
P0689
* The ECM detects less than 5 V on the ignition 1 voltage circuit to the ECM.
* The condition is present for more than 5 s.
P0690
* The ECM detects more than 16 V on the ignition 1 voltage circuit to the ECM when the relay is commanded ON.
* The ECM detects more than 2 V on the ignition 1 voltage circuit to the ECM when the relay is commanded OFF.
* The condition is present for more than 2 s.
Action Taken When the DTC Sets
DTCs P0685, P0689, and P0690 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P0685, P0689, and P0690 are Type B DTCs.
Diagnostic Aids
This test procedure requires that the vehicle battery has passed a load test and is completely charged. Refer to Battery Inspection/Test Battery Inspection/Test.
Reference Information
Schematic Reference
* Engine Controls Schematics [1][2]Electrical Diagrams
* Power Distribution Schematics Power Distribution Schematics
Connector End View Reference
Component Connector End Views Connector End Views By Name
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
* Probing Electrical Connectors Probing Electrical Connectors
* Electrical Center Identification Views Application and ID
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Programming and Relearning for scan tool information
Special Tools
* J 35616 GM-Approved Terminal Test Kit
* J 43244 Relay Puller Pliers
Circuit/System Verification
1. Ignition ON, engine OFF, command the powertrain relay ON and OFF, with a scan tool, while observing the following powertrain relay coil control circuit status parameters.
* Powertrain relay coil control Ckt. Short Gnd Test Status
* Powertrain relay coil control Ckt. Open Test Status
* Powertrain relay coil control Ckt. Short Volts Test Status
Each parameter should toggle between OK and Not Run or Not Run and OK
2. Ignition ON, observe the DTC information with a scan tool. DTC P0685, P0689 or P0690 should not set.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Note: You must perform the Circuit/System Verification first.
1. Ignition OFF, disconnect the KR75 powertrain relay.
2. 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, test the relay battery voltage circuit for an open/high resistance or a short to ground.
Note: The ignition voltage circuit is between the powertrain relay and the ECM. The ignition voltage is a feedback circuit.
3. Ignition OFF, verify that a test lamp does not illuminate between the ignition voltage circuit terminal 87 and ground.
• If the test lamp illuminates, test the ignition voltage circuit for a short to voltage.
4. Connect a 20 A fused jumper wire between the relay switch B+ circuit terminal 30 and the relay switch ignition voltage circuit terminal 87.
5. Ignition ON, observe the scan tool EC Ignition Relay Feedback Signal parameter. The ECM should communicate, and the parameter should display 9-14 V.
• If not the specified range, or the ECM does not communicate, 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 K20 ECM.
6. Ignition OFF, verify that a test lamp does not illuminate between the control circuit terminal 86 and B+.
• If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
7. Connect a DMM set to the diode setting between the control circuit terminal 86 and ground.
8. Ignition ON, verify the DMM does not display OL.
• If the DMM displays OL, test the control circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
9. If all circuits test normal, replace the KR75 powertrain relay.
Component Testing
Note: Depending on the application, the relay coil resistance will be within one of the following ranges.
1. Test for one of the following resistance specifications between terminals 85 and 86 of the KR75 powertrain relay:
* 70-100 ohm
* 200-250 ohm
• If not within the specified range, replace the KR75 powertrain relay.
2. Test for the infinite resistance between the following terminals to the KR75 powertrain relay:
* 30 and 86
* 30 and 87
* 30 and 85
* 85 and 87
• If not the specified value, replace the KR75 powertrain 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 KR75 powertrain relay.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Relay Replacement
* Control Module References Programming and Relearningfor ECM replacement, setup, and programming