Technical Description of OBD-II Trouble Code
The fuel injector in cylinder 5 is leaking.
What does that mean?
This is a generic diagnostic trouble code (DTC) that applies to OBD-II vehicles. This includes vehicles from various manufacturers. Although it is a generic code, the specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
If your OBD-II equipped vehicle has stored a code P02AD, it means that the powertrain control module (PCM) has detected a possible fuel injector leak in cylinder #5 of the engine.
Automotive fuel injectors need to maintain a precise fuel pressure to deliver the correct amount of fuel in a specific spray pattern to each cylinder’s combustion chamber. To achieve this precision, fuel injectors must be free of leaks and restrictions.
The PCM monitors various factors such as fuel trim requirements, exhaust oxygen sensor data, crankshaft position, and camshaft position to detect a lean condition and identify the specific cylinder with the malfunction. Oxygen sensor data alerts the PCM to a lean exhaust condition and indicates which bank of the engine is affected. By analyzing the position of the camshaft and crankshaft, the PCM can determine which fuel injector is experiencing a problem. Once the PCM identifies a lean condition and locates the affected fuel injector in cylinder #5, it stores a code P02AD and may illuminate the malfunction indicator lamp (MIL).
In some cases, multiple failure cycles may be required for the MIL to illuminate.
A cross section of a typical fuel injector:
What is the severity of this DTC?
A P02AD code should be considered severe because a lean fuel condition could potentially cause damage to the cylinder head or engine.
What are some of the symptoms of the code?
Symptoms of a P02AD trouble code may include:
What are some of the common causes of the code?
Possible causes for this P02AD fuel injector code may include:
What are some P02AD troubleshooting steps?
Prior to diagnosing a code P02AD, it is recommended to diagnose and repair any MAF and MAP related codes.
Start the diagnosis by inspecting the fuel injection rail area. Focus on the fuel injector in cylinder #5. Check for signs of corrosion or leakage on the exterior of the fuel injector. If heavy corrosion or leakage is present, it is likely that the fuel injector has failed.
If no obvious mechanical issues are found in the engine bay, several tools will be needed for an accurate diagnosis:
Connect the scanner to the vehicle’s diagnostic port and retrieve all stored codes and freeze frame data. This information will be helpful during the diagnosis. Clear the codes and test-drive the vehicle to see if the P02AD code reappears.
If the P02AD code immediately returns, use the scanner to perform an injector balance test to confirm that the misfire is caused by an injector problem. Once this is confirmed, proceed to step 1.
Step 1
With the engine running, use the stethoscope to listen to the fuel injector in question. You should hear a repeated clicking sound in a specific pattern. If there is no sound at all, proceed to step 2. If the sound is strained or intermittent, suspect that the injector for cylinder #5 has failed or is clogged. If needed, compare the sounds from that cylinder’s injector to others for comparison.
Step 2
Use the DVOM to test for voltage and a ground pulse while the engine is running. Most manufacturers use a system where one terminal of the fuel injector receives constant battery voltage, while the other terminal receives a ground pulse from the PCM at the appropriate time.
If no voltage is detected at the connector of the fuel injector in question, use the DVOM to test the system fuses and relays. Replace any faulty fuses and/or relays.
It is recommended to test system fuses with the circuit under a load. A fuse that appears to be good when the circuit is not loaded (key on/engine off) may fail when the circuit is loaded (key on/engine running).
If all system fuses and relays are functioning properly and there is still no voltage, use the vehicle information source to trace the circuit back to the ignition switch or fuel injection module (if applicable).
Note: Exercise caution when testing/replacing high-pressure fuel system components.
