What does it mean?
P1323 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: ICM 24X Reference Circuit Low Frequency .
Symptoms
- MIL (check engine lamp) on
- Rough running, misfire and hesitation, most noticeable at low rpm
- Long cranking and hard starting
- Intermittent stalling, sometimes without warning
- Tachometer reading unstable or dropping while driving
Likely causes
- Damaged reluctor ring with worn, chipped or missing teeth
- Crankshaft position sensor air gap out of specification, or the sensor loose in its bore
- Metal debris built up on the sensor tip, common after internal engine wear
- Failing crankshaft position sensor with a weak output
- Open, chafed or electrically noisy 24X reference wire between the ignition module and the engine control module
- Failed ignition control module
- Poor grounds allowing interference to corrupt the pulse train
How to fix it
- Read the freeze frame and note the rpm and load when the fault was recorded
- Remove the crankshaft sensor and inspect the tip for metal debris, then check the air gap against specification
- Inspect the reluctor ring for damaged, missing or bent teeth
- Measure or scope the 24X signal frequency and compare it with the engine speed
- Test the reference wire for continuity, chafing and shorts to ground
- Clean and retighten the ignition module and engine ground points
- Replace the crankshaft sensor or the ignition control module once the mechanical and wiring checks are complete