Applicable Systems
OBD-II
Symptoms
CKP sensor signal intermittent or out of expected range; engine may run rough or stall intermittently.
Possible Causes
- CKP sensor intermittent signal loss
- Sensor connector loose
- Flywheel reluctor wheel intermittent damage
Troubleshooting Steps
- Step 1: Monitor CKP sensor signal on oscilloscope
Clean square/sine wave pattern - Step 2: Check sensor connector for loose pins
Connector tight - Step 3: Inspect reluctor wheel for damage at multiple points
All teeth intact - Step 4: Replace CKP sensor if signal intermittent
New sensor signal clean - Step 5: Clear code and perform crank relearn
Signal stable, no codes
How to Reset
Clear with OBD-II scanner; perform crank position relearn.
Common Replacement Parts
- Crankshaft Position Sensor (OEM spec)
Frequently Asked Questions
- Q: What is crank position relearn?
Procedure where ECM learns the exact CKP sensor signal pattern relative to TDC. Performed via OBD-II scanner. Required after sensor or flywheel replacement.
Source: SAE J2012 standard DTC list + OBD-II portal
Category: OBD-II