P0301

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Steps 6 - 10:

Steps 11 - 12:

DTC P0301 Cylinder 1 Misfire Detected

Circuit Description
The powertrain control module (PCM) has the ability to detect a misfire by monitoring the 58X reference and the camshaft position sensor input signals. If the PCM detects a crankshaft speed variation that indicates 1% or more of cylinder firing events are misfires, the PCM will disable the torque converter clutch (TCC). It the RPM variation detected indicates a misfire, the PCM attempts to calculate which cylinder is misfiring by associating crankshaft angle (using the camshaft position sensor signal) with the RPM variation (using the 58X reference). If cylinder #1 isolated as the misfiring cylinder, DTC P0301 will set.
If the ABS Rough Road sensor input signal to the PCM determines that a rough road condition is present, the misfire diagnostic will be temporarily disabled.

Conditions for Setting the DTC
- None of the following DTCs occur: TP sensor, MAF sensor, camshaft position sensor, vehicle speed sensor, ECT sensor, ABS Rough Road sensor, crankshaft position sensor.
- The engine speed is between 600 and 6250 RPM.
- The system voltage is between 11 and 16 volts.
- The ECT indicates an engine temperature between -7 °C (28 °F) and 120 °C (248 °F).
- The throttle angle is steady.
- The PCM is detecting a crankshaft RPM variation that indicates a misfire on cylinder #1 sufficient to cause three-way catalytic converter damage or emissions levels to exceed mandated standard.

Action Taken When the DTC Sets
- The PCM will illuminate the malfunction indicator lamp (MIL) the first time the fault is detected.
- If the misfire is severe enough to cause possible catalyst damage, the PCM will flash the MIL for as long as the misfire remains at catalyst damaging levels.
- The PCM will store conditions which were present when the DTC was set as Freeze Frame and in the Failure Records data.

Conditions for Clearing the MIL/DTC
- The PCM will turn the MIL OFF on the third consecutive ignition cycle in which the diagnostic has been run and the fault condition is no longer present.
- A history DTC P0301 will clear after 40 consecutive ignition cycles occur without a fault. A
- DTC P0301 can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

Diagnostic Aids
Check for the following conditions:
- System grounds - Ensure all connections are clean and properly tightened.
- Injector - Perform the injector coil/balance test to locate a faulty injector that contributes to a lean condition on the affected cylinder. In addition to the above test, check the condition of the injector 0-ring.
- Faulty spark plug - Check for a cracked insulator, carbon tracking, incorrect gap, and worn electrodes.
- Damaged or faulty ignition coil - Check for cracks or other damage.
- Substitute a known good coil - Swap the ignition coils and retest. If the misfire follows the coil, replace the ignition coil.