This article explains the P1336 diagnostic trouble code (DTC) and its relation to the Crankshaft Position (CKP) system variation learning procedure, often referred to as CASE (Crankshaft Angle Sensor Error) relearn. A practical approach to performing this relearn using a Tunerpro ADX script and a USB AVT OBD-II cable is also discussed.
CASE Relearn Process and Monitoring
A Tunerpro ADX script can automate the CASE relearn process and provide real-time feedback via a USB AVT OBD-II interface. Observing specific parameters on the dashboard during the process is crucial.
Key Dashboard Indicators
- Learn Active: This indicator turns blue and displays “Yes” when the relearn process is active.
- CKP Request OK’d: A “Yes” status confirms that the Powertrain Control Module (PCM) has accepted the relearn request. A “No” indicates rejection, possibly due to an incorrect data frame for the model year or existing DTCs. While it should remain “Yes” throughout the relearn, a “No” after completion signifies a successful learn and the PCM rejecting further attempts.
Status Flags (Pre-2000 Model Year PCMs)
Older PCMs provide additional status flags:
- Cool temp too Low: Indicates the engine hasn’t reached the required operating temperature for the relearn.
- Too many attempts: Signals that the maximum number of relearn attempts has been exceeded.
- Errors Detected: This flag sets if a P1336 DTC is present after the relearn. While it doesn’t prevent PCM and sensor pairing, it indicates a potential issue. Other error flags relate to the crank encoder, cam sensor, or crank sensor and should ideally remain unset.
P1336 DTC and its Implications
The P1336 code signifies a discrepancy in the crankshaft position signal. This often necessitates a CASE relearn to synchronize the crankshaft and camshaft position sensors with the PCM. The relearn process involves monitoring the “Errors Detected” flag. While a P1336 after relearn might not prevent operation, it suggests further diagnostics are required.
Applicability to Various Vehicle Models
This method, developed and tested on a 1999 model, leverages the OBD logic within the Vortec PCM. While untested on newer VPW PCMs, the similar OBD architecture suggests potential compatibility. However, always consult specific vehicle documentation for confirmation.
Conclusion
Understanding the P1336 code and the CASE relearn process is vital for diagnosing and resolving crankshaft position sensor related issues. Utilizing tools like the Tunerpro script and monitoring dashboard parameters can significantly simplify this procedure. While this information provides a general guideline, referring to specific vehicle and PCM documentation remains crucial for accurate diagnosis and repair.
