P064C Glow Plug Control Module
OBD-II Trouble Code Technical Description
Glow Plug Control Module
What does that mean?
This is a generic diagnostic trouble code (DTC) and applies to many OBD-II vehicles (1996-newer). That may include but is not limited to vehicles from Chrysler, Ford, General Motors, Mercedes-Benz, Nissan, Toyota, etc. Although generic, the exact repair steps may vary depending on year, make, model, and powertrain configuration.
A stored code P064C means that the powertrain control module (PCM) has detected a malfunction in the glow plug control module.
The glow plug control module is responsible for initiating the glow plug preheater timer and the glow plug for each individual cylinder. Glow plugs, the glow plug timer, and the glow plug controller are used exclusively in vehicles with diesel propulsion systems.
The glow plug control module may be a stand-alone module but it is most often an integral part of the PCM.
Each time the ignition is turned on and the PCM is energized, multiple controller self-tests are performed. By performing controller self-tests, the PCM can monitor serial data that is carried over the controller area network (CAN) to ensure that on-board controllers are interfacing properly.
If a problem is detected in monitoring the glow plug control module, a code P064C will be stored and a malfunction indicator lamp (MIL) may be illuminated.
A typical glow plug:
What is the severity of this DTC?
Glow plug control module codes may result in lack of glow plug function and create an engine no-start condition. The code P064C should be classified as severe.
What are some of the symptoms of the code?
Symptoms of a P064C trouble code may include:
One or more incapacitated glow plugs Delayed engine start-up (especially during cold weather) Engine stall at start-up Engine drivability issues Other stored codesWhat are some of the common causes of the code?
Causes for this code may include:
Faulty glow plug controller or PCM Open glow plug control module voltage supply circuit PCM programming error Open or shorted glow plug control circuitWhat are some P064C troubleshooting steps?
A diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of reliable vehicle information will be required to diagnose a code P064C.
Consult your vehicle information source for technical service bulletins (TSB) that replicate the code stored, vehicle (year, make, model, and engine), and symptoms exhibited. If you find the appropriate TSB, it may yield helpful diagnostic information.
Begin by connecting the scanner to the vehicle diagnostic port and retrieving all stored codes and freeze frame data. You will want to write this information down, just in case the code proves to be an intermittent one. After recording all pertinent information, clear the codes and test drive the vehicle (if possible) until the code is reset or the PCM enters readiness mode.
If the PCM enters readiness mode, the code is intermittent and will be more difficult to diagnose. The condition, which caused the P064C to be stored, may need to worsen before an accurate diagnosis can be reached. If the code is reset, continue with your diagnosis.
Use your source of vehicle information to obtain connector face views, connector pin-out charts, component locators, wiring diagrams, and diagnostic flow charts related to the code and vehicle in question.
Check to see if there is battery voltage on the glow plug control circuit by using the appropriate wiring diagram and your DVOM. If not check system fuses and relays and replace defective parts as required.
If there is no voltage (and/or ground) on the glow plug control circuit (and all fuses and relays appear to be functioning properly) an inspection of controller related wiring and harnesses is in
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