P0321
PowertrainCrankshaft Camshaft Positionhigh severityIgnition/Distributor Engine Speed Input Circuit Range/Performance
What P0321 Means
The engine speed signal from the ignition or distributor sensor is present but out of expected range. This often means erratic or intermittent RPM readings that confuse the PCM.
Symptoms
- Erratic tachometer readings
- Hard starting or stalling
- Intermittent misfire feel
Common Causes
- Faulty crankshaft/RPM sensor
- Damaged sensor wiring or connector
- Reluctor ring damage
- Faulty ignition module
Diagnostic Steps
- Scan for related codes and freeze frame
- Inspect sensor wiring and connectors
- Check sensor signal with scope during crank
- Test reluctor ring and sensor air gap
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Serious DIY~$100
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✓ Autel official store
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