P0321 - Ignition/Distributor Engine Speed Input Circuit Range/Performance
The P0321 code indicates that the Engine Control Module (ECM) has detected an issue with the ignition/distributor engine speed input circuit. This circuit is responsible for sending the engine speed (RPM) signal from the distributor or crankshaft position sensor to the ECM. The code is set when the signal is out of the expected range or performance parameters, often due to a faulty sensor, wiring issues, or a failing distributor.
01. Most Common Causes
- Faulty crankshaft position sensor
- Damaged or corroded wiring/connectors in the sensor circuit
- Failing distributor (if equipped)
- ECM software or hardware issue
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine misfire or rough idle
- Difficulty starting or stalling
- Poor acceleration or hesitation
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for related codes.
Step 2: Visually inspect the crankshaft position sensor and distributor wiring for damage or corrosion.
Step 3: Test the sensor's resistance and voltage output with a multimeter per manufacturer specs.
Step 4: Check the distributor cap and rotor for wear if applicable.
Step 5: If all else fails, test the ECM for proper signal reception.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the vehicle may stall or lose power unexpectedly, posing a safety risk.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on the specific cause and vehicle model.