J35Z3
Advanced DiagnosticsDTC P0301: No. 1 Cylinder Misfire Detected (Engine Type: J35Z3)
DTC P0302: No. 2 Cylinder Misfire Detected (Engine Type: J35Z3)
DTC P0303: No. 3 Cylinder Misfire Detected (Engine Type: J35Z3)
DTC P0304: No. 4 Cylinder Misfire Detected (Engine Type: J35Z3)
DTC P0305: No. 5 Cylinder Misfire Detected (Engine Type: J35Z3)
DTC P0306: No. 6 Cylinder Misfire Detected (Engine Type: J35Z3)
General Description
The crankshaft vibrates slightly when each cylinder fires. If a misfire occurs, the crankshaft rotation speed changes rapidly. The engine control module (ECM) monitors engine misfiring based on the output pulses from the crankshaft position (CKP) sensor, counts the number of misfires, and determines which cylinder is misfiring. If a misfire is detected, a DTC is stored.
There are two types of misfire detection.
Type 1 (1 drive cycle): When the number of misfires per 200 engine revolutions reaches the level that damages the three way catalyst (TWC), a DTC is stored and the MIL blinks. When the misfire ceases, the MIL remains on steady instead of blinking.
Type 2 (2 drive cycles): When the number of misfires per 1,000 engine revolutions reaches the level that affects FTP mode exhaust emissions, a DTC is stored and the MIL comes on.
Monitor Execution, Sequence, Duration, DTC Type, OBD Status
Enable Conditions
Malfunction Threshold
Driving Pattern
1. Start the engine. Hold the engine speed at 3,000 rpm without load (in neutral) until the radiator fan comes on.
2. Drive the vehicle at a speed between 15 - 75 mph (24 - 120 km/h) for at least 3 minutes.
3. Stop the vehicle, and let the engine idle for at least 3 minutes.
- When freeze frame data is stored, drive the vehicle under those conditions instead of Driving Patterns 2 or 3.
- When you have difficulty duplicating the DTC because of road conditions and traffic situations, repeat the driving pattern several times.
- Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
Diagnosis Details
Conditions for illuminating the MIL
Misfire Type 1:
- If a type 1 misfire (catalyst damaging) occurs once, the MIL blinks once per second, a Temporary DTC is stored, and the high rpm fuel injection stop system activates. The fuel injection stops, at high rpm only, on the cylinder that has the highest misfire counts. the MIL continues to blink and the fuel injection stays off at high rpm, until the drive is completed.
- If a type 1 misfire occurs during a second drive cycle, the MIL and fuel injection behave the same and a DTC is stored.
- After a type 1 misfire has been detected during two drive cycles, the MIL comes on and stays on solid beginning with the third drive cycle, unless the Temporary DTC has been cleared by the ECM*. Even if the MIL is on, it will start blinking if a type 1 misfire occurs.
- If the malfunction recurs during the next (second) drive cycle, the MIL comes on and the DTC and the freeze frame data are stored.
Misfire Type 2:
If a type 2 misfire (emission-related but not severe enough to immediately damage the catalyst) occurs, a Temporary DTC is stored, but the MIL does come on or blink. If a type 2 misfire occurs during a second drive cycle, the MIL comes on and stays on unless the Temporary DTC has been cleared by the ECM*.
- The temporary DTC is erased under these conditions:
- The vehicle is operated under the same driving conditions as the first misfire detection, and no misfire is detected.
- 80 drive cycles are completed with no misfire detected.
Conditions for clearing the MIL
The MIL will be cleared if the malfunction does not recur during three consecutive drive cycles in which the engine conditions are similar to the first time the malfunction was detected. The MIL, the DTC, the Temporary DTC, and the freeze frame data can be cleared by using the scan tool Clear command or by disconnecting the battery.