P0320
UniversalIgnition/Distributor Engine Speed Input Circuit Malfunction
High SeverityThe P0320 code indicates a problem with the electrical circuit that provides engine speed information to the vehicle's computer, often involving the crankshaft position sensor or distributor signal. This malfunction can cause the engine to run poorly, stall unexpectedly, or prevent it from starting at all, significantly impacting the vehicle's reliability.
⚠️ Before You Begin (Safety First)
Always ensure the vehicle is on a stable, level surface and the engine is off and cool before beginning any inspection or repair. Disconnect the battery's negative terminal before working on electrical components to prevent accidental shorts or injury. Wear appropriate eye protection and gloves.
Common Symptoms
- Check Engine Light illuminated
- Engine cranks but won't start
- Engine stalls unexpectedly
- Rough idle or misfires
- Reduced engine power
- Erratic speedometer/tachometer readings (less common)
Common Causes
- Faulty Crankshaft Position Sensor
- Faulty Camshaft Position Sensor (if applicable)
- Damaged or corroded wiring or connectors in the ignition/distributor circuit
- Faulty ignition coil or distributor pickup coil
- Loose connection at the PCM
- Faulty Powertrain Control Module (PCM) - rare
Frequently reported on: 1998-2005 Ford F-150, 2000-2006 Chevrolet Silverado, 1996-2004 Honda Civic, 1999-2005 Jeep Grand Cherokee
Diagnostic Steps
- Inspect the wiring harness and connectors leading to the crankshaft position sensor, camshaft position sensor, and distributor (if equipped) for any visible damage, corrosion, or loose connections. Repair as needed.
- Using a multimeter, test the resistance and voltage output of the crankshaft position sensor according to manufacturer specifications.
- If the vehicle has a distributor, inspect the distributor cap, rotor, and pickup coil for wear or damage.
- If testing indicates a fault, replace the suspected sensor (crankshaft position sensor, camshaft position sensor, or distributor pickup coil).
- Clear the code with an OBD-II scanner and test drive the vehicle to confirm the repair.
👨🔧 When to Call a Professional
While inspecting wiring and replacing the crankshaft position sensor or distributor components can often resolve this code, if the issue persists or if there are intermittent symptoms, a professional diagnostic technician should be consulted to accurately test the circuit's integrity and rule out potential PCM issues.
Commonly Asked Questions
What specifically does P0320 mean?
P0320 indicates that the engine's computer is not receiving a correct or consistent engine speed signal from the ignition system or distributor, which is critical for proper engine operation.
Can a bad ignition coil cause a P0320 code?
Yes, a faulty ignition coil, especially in older systems where it's part of the engine speed input circuit, can sometimes trigger a P0320 code. However, the crankshaft position sensor is a more common culprit.
Is it safe to drive with a P0320 code?
It is generally not safe to drive with a P0320 code because the engine may stall unexpectedly or fail to start, potentially leaving you stranded or causing dangerous situations on the road.
How do I diagnose P0320 if I've already checked the sensor?
If the sensor checks out, thoroughly inspect the entire wiring harness for breaks, shorts, or corrosion from the sensor to the PCM. You may also need to check the PCM's power and ground connections or test its input signal with an oscilloscope.
Can this code be related to P0300 (Random Misfire)?
Yes, absolutely. An inaccurate or missing engine speed signal from a P0320 fault can directly lead to the engine's computer miscalculating ignition timing and fuel delivery, resulting in misfires and potentially triggering P0300 or specific cylinder misfire codes.