DTC P1336
Circuit Description
The Crankshaft Position (CKP) sensor sends pulses to the PCM when the reluctor wheel teeth rotate past the CKP sensor. The PCM uses the CKP pulses in order to synchronize the ignition and the fuel injector operation, and in order to time the interval between each CKP pulse. The PCM determines when an excessive change in the crankshaft speed occurs by comparing each new time interval with the previous interval. A misfire causes an unexpected change in the crankshaft speed. A certain amount of acceleration or deceleration is expected between each firing stroke, but if the crankshaft speed changes more than an expected amount, the PCM interprets this as a misfire. The interval between CKP sensor pulses is extremely small. At high engine speeds, slight variations in the following components make misfire detection difficult:
- The crankshaft
- The reluctor wheel
- The CKP sensor
The PCM learns variations during the Crankshaft Position System Variation Learning Procedure. The PCM compensates for these variations when it performs detect misfire calculations. Only a scan tool can command the PCM to perform the Crankshaft Position System Variation Learning Procedure again.
After the following actions, perform the learning procedure:
- A PCM replacement
- Any operation or repair involving the crankshaft, the CKP sensor, or the CKP sensor to reluctor wheel gap relationship.
- An engine replacement
- The ignition switch is in the ON position until the battery is drained.
Important
A PCM power disconnect with the ignition ON may erase the stored pulse value and set the DTC P1336.
Disconnecting the PCM will not erase the learned Crankshaft Position System Variation as long as the ignition switch is in the OFF position.
Important
Reprogramming the PCM does not require running the Crankshaft Position System Variation Learn Procedure unless the PCM is new or is from another vehicle.
A DTC P1336 sets if the Crankshaft Position System Variation is not within an acceptable range, or cannot be learned.
Conditions for Running the DTC
DTCs P0335, P0336, P0341, P0342, and P0343 are not set.
Conditions for Setting the DTC
The PCM has not learned the Crankshaft Position System Variation.
Action Taken When the DTC Sets- The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.
Conditions for Clearing the MIL/DTC- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.