P0675
DTC P0671-P0678
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 Instructions)provides an overview of each diagnostic category.
DTC Descriptors
DTC P0671
- Cylinder #1 Glow Plug Control Circuit
DTC P0672
- Cylinder #2 Glow Plug Control Circuit
DTC P0673
- Cylinder #3 Glow Plug Control Circuit
DTC P0674
- Cylinder #4 Glow Plug Control Circuit
DTC P0675
- Cylinder #5 Glow Plug Control Circuit
DTC P0676
- Cylinder #6 Glow Plug Control Circuit
DTC P0677
- Cylinder #7 Glow Plug Control Circuit
DTC P0678
- Cylinder #8 Glow Plug Control Circuit
Diagnostic Fault Information
Circuit/System Description
The glow plug control module has the ability to perform internal checks for an open or a short to ground on each of the glow plug circuits. If the glow plug control module senses a problem in a glow plug circuit, the glow plug on the affected cylinder will be disabled and the glow plug control module will send an error message to the engine control module (ECM). If this condition exists, the appropriate DTC will set.
Conditions for Running the DTC
* The ignition is ON.
* DTCs P0671-P0678 run continuously.
Conditions for Setting the DTC
The glow plug control module detects that the glow plug control circuit is open, shorted to ground, or has more than 1 ohm of resistance.
Action Taken When the DTC Sets
DTCs P0671-P0678 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P0671-P0678 are Type B DTCs.
Diagnostic Aids
If the battery is connected with the ignition ON, the glow plugs could be damaged without finding any circuit fault.
Reference Information
Schematic Reference
Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Glow Plug System Description (Description and Operation)
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)
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
Circuit/System Verification
1. Ignition ON, using a scan tool observe the following parameters:
* Glow Plug 1
* Glow Plug 2
* Glow Plug 3
* Glow Plug 4
* Glow Plug 5
* Glow Plug 6
* Glow Plug 7
* Glow Plug 8
All parameters should closely match each other.
2. 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
Note: If a glow plug is replaced and the tip is missing or burned off, the cylinder head must be removed and all debris be cleaned out of the cylinder.
1. Ignition ON, glow plugs not commanded ON, verify that a test lamp does not illuminate between the appropriate Glow Plug Supply Voltage circuit terminal A and ground.
• If the test lamp does illuminate, test the glow plug control circuit for a short to voltage. If the circuit tests normal, replace the K34 glow plug control module.
2. Command the Glow Plugs ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
• If the test lamp does not turn ON and OFF, test the appropriate glow plug control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K34 glow plug control module.
3. If all circuits test normal, test or replace the appropriate E12 glow plug.
Component Testing
1. Igniting OFF, disconnect the harness connector of the appropriate glow plug.
2. Testing for less than 1 ohm between terminal A and ground.
• If the resistance is more than 1 ohm, replace the affected glow plug.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Glow Plug Replacement - Bank 1 (Glow Plug Replacement - Bank 1)
* Glow Plug Replacement - Bank 2 (Glow Plug Replacement - Bank 2)
* Control Module References (Programming and Relearning)for glow plug control module replacement, programming, and setup.
Repair Verification
1. Install any components or connectors that have been removed or replaced during diagnosis.
2. Perform any adjustment, programming, or setup procedures that are required when a component or module is removed or replaced.
Note: The glow plugs must be commanded ON before the GPCM will clear DTC P0671-P0678.
3. Ignition ON, with a scan tool, command the glow plugs ON.
4. Clear the DTCs.
• If DTC P0671-P0678 is present, a condition with the system still exists.