Applicable Systems
OBD-II
Symptoms
Engine speed input circuit to ignition module malfunction; engine may not start or run erratically.
Possible Causes
- Crankshaft position sensor signal loss to ignition module
- Ignition module internal failure
- Wiring between CKP sensor and ignition module open
Troubleshooting Steps
- Step 1: Check CKP sensor signal at ignition module
Signal present - Step 2: Inspect wiring from CKP to module
Wiring intact - Step 3: Check ignition module power and ground
Power and ground good - Step 4: Replace CKP sensor if signal absent
Signal present with new sensor - Step 5: Replace ignition module if signal present but no output
Engine starts
How to Reset
Clear with OBD-II scanner after repair.
Common Replacement Parts
- Crankshaft Position Sensor
- Ignition Module (if equipped)
Frequently Asked Questions
- Q: Do modern cars have distributors?
Most post-2000 vehicles use coil-on-plug (COP) or coil pack systems, no distributor. CKP sensor directly feeds ECM, not a separate ignition module.
Source: SAE J2012 standard DTC list + OBD-II portal
Category: OBD-II