The P0384: Glow Plug Control Module Control Circuit High code indicates that the engine control module (ECM) has detected a higher-than-expected voltage in the glow plug control module circuit. The glow plug control module manages the power supply to the glow plugs, which are crucial for starting a diesel engine, especially in cold conditions. High voltage in this circuit can prevent proper glow plug operation, leading to poor starting performance or damage to components.
P0384 – Quick Overview
| Meaning | P0384: Glow Plug Control Module Control Circuit High |
| Is it serious? | Yes, this code can lead to glow plug system malfunctions, causing hard starts or preventing the engine from starting. |
| Possible causes | – Faulty glow plug control module – Wiring issues – High voltage at the control module |
| How to diagnose? | – Test the glow plug control module – Check for high voltage at the control module – Inspect wiring for shorts or damage |
P0384 Meaning
The P0384: Glow Plug Control Module Control Circuit High code means that the ECM is detecting a higher-than-expected voltage in the control circuit of the glow plug module. The glow plug control module regulates the operation of the glow plugs in a diesel engine, and high voltage can indicate issues such as a short circuit or a fault within the module, leading to improper glow plug function.
Step-by-step diagnostic guide
Follow these steps to diagnose and resolve the P0384 code by addressing potential causes one by one.
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check for additional related codes. Codes related to the glow plug system may help further pinpoint the issue. | OBD-II Scanner |
| Test the Glow Plug Control Module | Use a multimeter to test the glow plug control module. Measure the output voltage and compare it to manufacturer specifications to ensure it is within the proper range. | Multimeter, Manufacturer’s Specifications |
| Check for High Voltage at the Control Module | Measure the incoming voltage to the control module to check for any excess voltage that could be causing the issue. Ensure that the voltage is within the expected range. | Multimeter, Manufacturer’s Specifications |
| Inspect Wiring for Shorts or Damage | Inspect the wiring leading to and from the glow plug control module for signs of damage, fraying, or short circuits that could cause high voltage. Repair or replace damaged wiring as needed. | Flashlight, Wiring Repair Kit |
| Replace Faulty Components | If the glow plug control module is faulty or the wiring is damaged, replace the necessary components to ensure the system operates correctly. | Replacement Glow Plug Control Module, Safety Gloves |
| Clear the Code and Test Drive | After making repairs, clear the P0384 code using an OBD-II scanner. Test drive the vehicle to ensure the problem is resolved and the glow plug system is functioning properly. | OBD-II Scanner, Vehicle Owner’s Manual |
| Recheck for Codes | After the test drive, re-scan the vehicle to confirm that the P0384 code has not returned. If the code reappears, further diagnosis may be needed. | OBD-II Scanner |
This diagnostic guide will help you resolve the P0384 code by ensuring the glow plug control module operates within the correct voltage range and the wiring is free from shorts or damage, ensuring proper glow plug function and reliable engine starting.
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I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko