P06C5 Incorrect glow plug cylinder 1

P06C5 Incorrect glow plug cylinder 1

OBD-II DTC Datasheet

Incorrect glow plug cylinder 1

What does this mean?

This is a generic powertrain diagnostic trouble code (DTC) and is commonly applied to OBD-II vehicles. This may include but is not limited to VW, Audi, Ford, GMC, Ram, Chevy, etc. According to some reports, this code seems to be found mainly on Volkswagen / VW vehicles. Although general, the exact repair steps may vary depending on the model year, make, model, and transmission configuration.

When the P06C5 code persists, it means the powertrain control module (PCM) has detected the wrong degree of resistance in the glow plug circuit for cylinder # 1. Consult a reliable vehicle information source to determine the location of cylinder # 1 for your year / make / model. / transmission configuration.

Diesel engines use strong compression instead of a spark to start the piston movement. Since there is no spark, the cylinder temperature must be increased for maximum compression. For this, glow plugs are used in each cylinder.

The individual cylinder glow plug, which is often confused with spark plugs, is screwed into the cylinder head. Battery voltage is supplied to the glow plug element through the glow plug timer (sometimes called the glow plug controller or glow plug module) and / or the PCM. When voltage is applied correctly to the glow plug, it literally glows red hot and raises the temperature of the cylinder. As soon as the cylinder temperature reaches the desired level, the control unit limits the voltage and the glow plug returns to normal.

If the PCM detects unexpected resistance from the cylinder # 1 glow plug, a code P06C5 will be stored and a malfunction indicator lamp (MIL) may illuminate.

Photo of a typical glow plug:

What is the severity of this DTC?

Any code related to glow plugs is likely to come with driveability issues. The saved code P06C5 should be urgently referred to.

What are some of the symptoms of the code?

Symptoms of a P06C5 trouble code may include:

• Excessive black smoke from exhaust gases
• Engine control problems
• Delayed engine start
• Reduced fuel efficiency
• Engine misfire codes can be saved

What are some of the common causes for the code?

Reasons for this P06C5 fuel injector code may include:

• Defective or incorrect glow plugs
• Open or short circuit in the glow plug circuit
• Loose or defective glow plug connector
• Glow plug timer defective

What are some steps to troubleshoot the P06C5?

An accurate diagnosis of the P06C5 code will require a diagnostic scanner, a reliable source of vehicle information, and a digital volt / ohmmeter (DVOM). Use your vehicle information source to find the appropriate Technical Service Bulletins (TSB). Finding a TSB that matches the make and model of the vehicle, the symptoms shown, and the stored code will help you diagnose.

You may also need to obtain diagnostic block diagrams, wiring diagrams, connector views, connector pinout diagrams, component locations, and component test procedures / specifications from your vehicle information source. All this information will be needed to correctly diagnose a stored P06C5 code.

After thoroughly visually inspecting all glow plug wiring and connectors and glow plug control, connect the diagnostic scanner to the vehicle diagnostic port. Now extract all stored codes and freeze frame data and write them down for later use (just in case you need them). Then I would test drive the car to see if the P06C5 code has been reset. Move until one of two things happens: either the PCM enters ready mode or the code is cleared. If the code is cleared, continue diagnostics. If not, you are dealing with a recurrent illness that may need to get worse before an accurate diagnosis can be made.

When performing this test, be careful not to burn yourself or cause a fire. My usual method of checking glow plugs is to remove them and apply battery voltage. If the glow plug glows bright red, that's good. If the incandescent does not heat up, it is faulty. In the case of a stored P06C5 code, you will need time to verify it with the DVOM. If it doesn't meet the manufacturer's specifications for resistance, consider it defective.

If the glow plugs are working properly, use the scanner to activate the glow plug timer and check the battery voltage (and ground) at the glow plug connector (use a DVOM). If no voltage is present, check the power supply for the glow plug timer or glow plug controller. Check all relevant fuses and relays according to the manufacturer's recommendations. In general, I find it best to test system fuses and fuses with a loaded circuit. A fuse for a circuit that is not loaded can be good (when it is not) and lead you to the wrong path of diagnosis.

If all fuses and relays work, use the DVOM to test the output voltage at the glow plug timer or PCM (wherever). If voltage is detected on the glow plug timer or PCM, suspect you have an open or short circuit. You can find the reason for the mismatch or simply replace the chain.

• Attempts to diagnose the wrong cylinder happen more often than you think. Save yourself a headache and make sure you are referring to the correct cylinder before starting your diagnosis.

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