P1336

P1171 Fuel Supply System Lean During Power Enrich

Circuit Description
In order to detect engine misfire at higher engine speeds, the powertrain control module (PCM)/engine control module (ECM) 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 (CKP) system variation learning procedure must be performed any time a change is made to the crankshaft sensor to crankshaft relationship of if the PCM/ECM is replaced or reprogrammed. The PCM/ECM measures the variations and then calculates compensation factors needed to enable the PCM/ECM to accurately detect engine misfire at all speeds and loads. A scan tool must be used to command the PCM/ECM to learn these variations. If for any reason the PCM/ECM is unable to learn these variations or they are out of an acceptable range, the PCM/ECM will set a DTC P1336. A PCM/ECM that has not had the CKP system variation learning procedure performed due to replacement or reprogramming will also set a DTC P1336.

Conditions for Setting the DTC
- DTCs P0117, P0118, P0121, P0122, P0123, P0336, P0337, P0341, P0342, P0502, P1627, P0722, P0723, and P1810 not set.
- Tooth error has not learned if mileage exceeds 100 miles since memory is cleared and the manufacture enable counter is set to zero.

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will illuminate.
- The PCM/ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffer.
- 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.
- DTCs can be cleared by using the scan tool.

Diagnostic Aids

CAUTION: To avoid personal injury 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 horn 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/ECM has not learned the CKP system variation. The PCM/ECM 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 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 cutoff rpm, the PCM/ECM is not in the learn procedure mode.

Step 1 - 6:

Test Description
The number(s) below refer to step(s) on the diagnostic table.
1. The On-Board Diagnostic (OBD II) 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 CKP system variation. Failure to properly warm the engine before performing this procedure will result in an inaccurate measurement of the CKP system variation. The PCM/ECM learns this variation as the engine is decelerating and then allows engine control to be returned to the operator. All accessories must be OFF when learning the CKP system angle variation. If the A/C is not disabled when the learn procedure is enabled, the PCM/ECM will disable the A/C.
3. If after the specified number attempts the PCM/ECM cannot learn the CKP 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 procedure indicates that the variation is out of range.