OBD-II Trouble Code Technical Description
The glow plug in cylinder 7 is incorrect.
What does that mean?
This is a generic powertrain diagnostic trouble code (DTC) that is typically found in OBD-II vehicles, including VW, Audi, Ford, GMC, Ram, Chevy, etc. However, it is most commonly seen in Volkswagen / VW vehicles. The exact repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
When the code P06CB is stored, it indicates that the powertrain control module (PCM) has detected an incorrect level of resistance in the glow plug circuit for cylinder #7. To determine the location of the #7 cylinder for 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 will glow red hot and help 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 with the cylinder #7 glow plug, it will store the code P06CB 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 P06CB promptly.
What are some of the symptoms of the code?
Symptoms of a P06CB trouble code may include:
What are some of the common causes of the code?
Possible causes for this P06CB fuel injector code may include:
What are some P06CB troubleshooting steps?
To accurately diagnose a code P06CB, 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 the make, model, symptoms, and stored code of the vehicle.
You may also need to obtain additional information such as diagnostic flow charts, wiring diagrams, connector face views, connector pin out charts, component locations, and component testing procedures/specifications from the vehicle information source. All of this information will be necessary for a correct diagnosis of the stored code P06CB.
After visually inspecting all glow plugs 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 P06CB is reset. If it is reset, continue with the diagnosis. If not, you may be dealing with an intermittent condition that may need to worsen before an accurate diagnosis can be made.
Be cautious when performing tests to avoid burns or starting a fire. 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 P06CB, it is recommended to test it with a DVOM. If it does not comply with the manufacturer’s resistance specifications, it should be 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 no voltage is present, 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 important to test system fuses and fusible links with the circuit loaded to avoid misdiagnosis.
If all fuses and relays appear to be functional, use the DVOM to test the output voltage at the glow plug timer or PCM. If voltage is detected at the glow plug timer or PCM, there may be an open or shorted circuit. You can investigate the cause of the discrepancy or simply replace the circuit.
