P1336

Diagnostic Chart:

Wiring Diagram:

Description:

Circuit Description
In order to detect engine misfire at higher engine speeds, the Powertrain Control Module (PCM) must know of any variation between the crankshaft sensor pulses. Most variations are due to the machining of the crankshaft reluctor wheel, however, other sources of variation are also possible. A Crankshaft Position System Variation Learning Procedure must be performed any time a change is made to the crankshaft sensor to crankshaft relationship or if the PCM is replaced or reprogrammed. The PCM measures the variations and then calculates compensation factors needed to enable the PCM to accurately detect engine misfire at all speeds and loads. A scan tool must be used to command the PCM to learn these variations. If for any reason the PCM is unable to learn these variations or they are out of an acceptable range, the PCM will set a DTC P1336. A PCM that has not had the Crankshaft Position System Variation Learning Procedure performed due to replacement or reprogramming will also set a DTC P1336.

Conditions for Setting the DTC

^ No crank or cam sensor DTCs.
^ PCM has not successfully learned crankshaft position system variation.

Action Taken When the DTC Sets

^ The Malfunction Indicator Lamp (MIL) will illuminate.
^ The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
^ A history DTC is stored.

Conditions for Clearing the MIL/DTC

^ The MIL will turn OFF after three consecutive ignition cycles in which the diagnostic runs without a fault.
^ A history DTC will clear after 40 consecutive warm up cycles without a fault.
^ DTC(s) can be cleared by using the scan tool.

Diagnostic Aids

Caution: When performing the Crankshaft Position System Variation Learning Procedure always set the vehicle parking brake and block the drive wheels. Release the throttle immediately when the engine starts to decelerate. Once the learn procedure is completed, engine control will be returned to the operator and the engine will respond to throttle position.

DTC P1336 will only set if the PCM has not learned the crankshaft position system variation. The PCM only needs to learn this variation once per life cycle of the vehicle unless the crank sensor to crankshaft relationship is disturbed. Removing a part for inspection and then reinstalling the same part is considered a disturbance. A fully warmed up engine is critical to learning the variation correctly. If a valid learn occurs, no other learns can be completed that ignition cycle.

If the engine cuts out before the specified learn procedure engine speed or at normal fuel cut-off Rpm, the PCM is not in the learn procedure mode. Review the Crankshaft Position System Variation Learning Procedure and re-enable the learn procedure. Verify that the scan tool says Test in Progress.

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored on the scan tool for later reference.

2. Engine temperature is critical to properly learn the crankshaft position system variation. Failure to properly warm the engine before performing this procedure will result in an inaccurate measurement of the crankshaft position system variation. The PCM learns this variation as the engine is decelerating and then allows engine control to be returned to the operator. All accessories must be turned OFF when learning the crankshaft position system angle variation. If the A/C is not disabled when the learn procedure is enabled the PCM will disable the A/C. When the PCM is ready to allow the learn procedure to run, the scan tool will display Test in Progress.

3. If after the specified number attempts the PCM cannot learn the crankshaft position system variation, then the variation is too large and no further attempts should be made until the variation problem is corrected.

4. Being unable to learn the crankshaft position system variation indicates that the variation is out of range. Using the Excessive Crankshaft Variation Troubleshooting will help to diagnose the area where the problem lies.