Technical Description of OBD-II Trouble Code
The glow plug in Cylinder 2 is incorrect.
What does that mean?
This is a generic diagnostic trouble code (DTC) that applies to OBD-II vehicles, including VW, Audi, Ford, GMC, Ram, Chevy, and others. However, it is commonly found in Volkswagen vehicles. The specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
When the code P06C6 is stored, it indicates that the powertrain control module (PCM) has detected an incorrect level of resistance in the glow plug circuit for Cylinder #2. To determine the location of Cylinder #2 in your specific vehicle, consult a reliable source of vehicle information.
In diesel engines, glow plugs are used to increase cylinder temperature and maximize compression, as there is no spark involved. Each cylinder has a glow plug threaded into the cylinder head, and when voltage is correctly applied, the glow plug becomes red hot and helps increase cylinder temperature. Once the desired temperature is reached, voltage is restricted and the glow plug returns to its normal state.
If the PCM detects an unexpected resistance in the glow plug for Cylinder #2, it will store the code P06C6 and may illuminate the malfunction indicator lamp (MIL).
Photo of a typical glow plug:
What is the severity of this DTC?
Any code related to glow plugs is likely to cause drivability issues. It is important to address a stored code P06C6 promptly.
What are some of the symptoms of the code?
Symptoms of a P06C6 trouble code may include:
What are some of the common causes of the code?
Possible causes for this P06C6 code may include:
What are some P06C6 troubleshooting steps?
To accurately diagnose a code P06C6, you will need a diagnostic scanner, a reliable source of vehicle information, and a digital volt/ohmmeter (DVOM). Use the vehicle information source to search for applicable technical service bulletins (TSB) that match your vehicle’s make, model, symptoms, and stored code.
You may also need additional information such as diagnostic flow charts, wiring diagrams, connector face views, connector pin out charts, component locations, and component testing procedures/specifications. After visually inspecting the glow plug and glow plug control wiring and connectors, connect the diagnostic scanner to the vehicle diagnostic port. Retrieve all stored codes and freeze frame data, and record them for reference. Test drive the vehicle to see if the code P06C6 is reset. If it is reset, continue with the diagnosis. If not, you may be dealing with an intermittent condition that requires further worsening for an accurate diagnosis.
Be cautious when performing tests to avoid burns or fires. One method to test glow plugs is to remove them and apply battery voltage. If the glow plug glows bright red, it is functioning properly. If it fails to heat up, it is defective. In the case of the stored code P06C6, use the DVOM to test the glow plug’s resistance. If it does not meet the manufacturer’s specifications, it is considered defective.
If the glow plugs appear to be working properly, use the scanner to activate the glow plug timer and test for battery voltage (and a ground) at the glow plug connector using the DVOM. If there is no voltage, test the power supply for the glow plug timer or glow plug controller. Test all related fuses and relays as recommended by the manufacturer. It is best to test system fuses and fusible links with the circuit loaded to avoid diagnostic errors.
If all fuses and relays are functional, use the DVOM to test the output voltage at the glow plug timer or PCM. If voltage is detected, there may be an open or shorted circuit. You can investigate the cause or simply replace the circuit.
