DTC P0683
Diagnostic Instructions
DTC Descriptor
DTC P0683 00: Glow Plug Control Module Communication Circuit Malfunction
DTC P0683 3A: Glow Plug Control Module Communication Circuit Incorrect Component Installed
DTC P0683 71: Glow Plug Control Module Communication Circuit Invalid Data
Circuit/System Description
The glow plug control module monitors the glow plugs, and control circuits for faults. This information is communicated to the engine control module (ECM) over a discrete communication circuit.
Conditions for Running the DTC
• | The ignition is ON or the engine is running. |
• | The ignition voltage is greater than 9 V. |
• | The DTCs run continuously once the above conditions are met. |
Conditions for Setting the DTC
P0683 3A
The ECM detects a glow plug control module hardware mismatch.
P0683 71
The ECM detects an invalid signal from the glow plug control module.
Action Taken When the DTC Sets
DTCs P0683 3A and P0683 71 are Type C DTCs.
Conditions for Clearing the DTC
DTCs P0683 3A and P0683 71 are Type C DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics : LLW
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
Circuit/System Verification
- Ignition ON, observe the DTC information with a scan tool. DTCs P0683 3A or P0683 71 should not set.
⇒ | If DTC P0683 3A is set, replace the K38 Ultrasonic Intrusion Sensor Module. |
- 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
- Ignition OFF, disconnect the harness connector at the K34 Glow Plug Control Module.
- Test for less than 5 Ω between the glow plug control module ground circuit terminal 7 and ground.
⇒ | If greater than the specified range, repair the ground circuit for an open/high resistance. |
- Ignition ON, verify a test lamp illuminates between the ignition 1 voltage circuit terminal 6 and ground.
⇒ | If the test lamp does not illuminate, repair the ignition 1 voltage circuit for a short to ground or an open/high resistance. |
- Test for greater than 10 V between the glow plug control module control circuit terminal 10 and ground.
⇒ | If less than the specified range, test the control circuit for an open or a short to ground. If the circuit tests normal, replace the K20 Engine Control Module. |
- Test for greater than 10 V between the glow plug control module communication circuit terminal 9 and ground.
⇒ | If less than the specified range, test the communication circuit for an open or a short to ground. If the circuit tests normal, replace the K20 Engine Control Module. |
- Test the DC frequency from the glow plug control module control circuit terminal 10. Command the glow plugs ON with a scan tool. Verify the DC frequency is between 30-35 Hz.
⇒ | If less than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module. |
⇒ | If greater than the specified range, test the control circuit for a high resistance. If the circuit tests normal, replace the K20 Engine Control Module. |
- Test the alternating current (AC) frequency from the glow plug control module communication circuit terminal 9. Command the glow plugs ON with a scan tool. Verify the AC frequency is between 30-35 Hz.
⇒ | If less than the specified range, test the communication circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module. |
⇒ | If greater than the specified range, test the communication circuit for a high resistance. If the circuit tests normal, replace the K20 Engine Control Module. |
- If all circuits test normal, test or replace the K34 Glow Plug Control Module.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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