Technical Description of OBD-II Trouble Code
Injection Timing for Cylinder 3
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that is applicable to most OBD-II equipped vehicles, including but not limited to VW Volkswagen, Dodge, Ram, Kia, Chevrolet, GMC, Jaguar, Ford, Jeep, Chrysler, Nissan, etc. Although it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
A stored code P020C indicates that the powertrain control module (PCM) has detected a malfunction in the injection timing circuit for a specific cylinder of the engine. In this case, the malfunction is related to cylinder three. To determine the exact location of cylinder number three for the vehicle in which the P020C code is stored, consult a reliable source of vehicle information.
Based on my experience, a code P020C is typically stored in vehicles equipped with diesel engines. Modern diesel engines that utilize clean burning (direct injection) technology require extremely high levels of fuel pressure.
Due to the high fuel pressure involved, only qualified individuals should attempt to diagnose or repair the high-pressure fuel system.
When unit injectors are used, the high-pressure injection pump is driven by the engine timing chain and timed according to the position of the crankshaft and camshaft/s. Each time the engine crankshaft and camshaft/s reach a specific point, the high-pressure injection pump is pulsed, resulting in an extremely high degree of fuel pressure (up to 35,000 psi).
Common rail direct injection systems use a common high-pressure fuel rail and individual solenoids for each cylinder. In this type of system, the PCM or a stand-alone diesel injection controller is responsible for controlling injector timing.
Inconsistencies in the timing of specific cylinder injections, caused by variations in camshaft and/or crankshaft timing, alert the PCM and trigger a stored code P020C. In some cases, multiple ignition cycles with a failure may be required for this type of code to be stored and for the malfunction indicator lamp to illuminate.
Other injection timing codes related to cylinders 1 through 12 include: P020A, P020B, P020D, P020E, P020F, P021A, P021B, P021C, P021D, P021E, and P021F
Severity of the Code & Symptoms
All codes related to the high-pressure fuel injection system should be considered severe and addressed with a sense of urgency.
Symptoms that may be associated with a P020C engine code include:
Possible Causes
Possible causes for the P020C code include:
Diagnostic and Repair Procedures
To diagnose a code P020C, I would need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information.
Begin by visually inspecting the components and wiring harnesses related to the high-pressure fuel system. Look for any signs of fuel leakage, as well as damage to the wiring or connectors.
Check for any technical service bulletins (TSB) that pertain to the vehicle, symptoms, and codes in question. If you find a relevant TSB, it can provide valuable information for diagnosing this code.
Next, connect the scanner to the vehicle’s diagnostic port and retrieve all stored trouble codes and freeze frame data. Make a note of this information, as it may be useful during the diagnosis process. Clear the codes and take the vehicle for a test drive to see if the code is reset. If there are any stored codes for the crankshaft sensor and/or camshaft position sensor, address and repair those issues before attempting to diagnose the injector timing code.
If the code is reset:
If the vehicle is equipped with a common rail injection system, use the DVOM and the vehicle information source to test the injector solenoid for the specific cylinder in question. Replace any component that does not meet the manufacturer’s specifications before proceeding. After repairing or replacing suspicious parts, clear any codes that may have been stored during testing and test drive the vehicle until the PCM enters readiness mode or the code is reset. If the PCM enters readiness mode, it indicates a successful repair. If the code is reset, there is still a problem that needs to be addressed.
If the injector solenoid is within specifications, disconnect the controller and use the DVOM to test the system circuits for shorts or opens. Repair or replace any system circuits that do not meet the manufacturer’s specifications, referring to the pin-out chart in your vehicle information source.
Unit injector failure is often associated with engine timing component failure or some type of high-pressure fuel system leak.
