P0320 – Meaning, Symptoms, Causes & How to Fix It

P0320 – Ignition/Distributor Engine Speed Input Circuit means the engine control unit is not receiving a proper engine speed (RPM) signal from the ignition system or distributor. This signal is critical for controlling spark, fuel delivery, and misfire detection. When the engine speed input is missing, erratic, or out of range, the ECU may trigger hard starting, stalling, or a no-start condition. This guide explains what P0320 means, its symptoms, causes, diagnosis steps, and the best repair solutions to restore proper engine operation.

What Does P0320 Mean?

P0320 is a generic OBD-II trouble code indicating a malfunction in the ignition/distributor engine speed input circuit. This system typically uses the crankshaft position sensor (CKP), camshaft position sensor (CMP), or distributor pickup to report engine speed to the ECU. When the ECU does not see a valid RPM signal, it cannot properly control ignition timing or fuel injection.

This code commonly appears on vehicles with distributor-based ignition systems, but it also applies to modern coil-on-plug engines where the PCM receives the engine speed signal from the CKP/CMP sensors.

Quick Reference

OBD-II Family: P-Code (Powertrain)
Scope: Generic
System: Ignition / Distributor / Engine Speed Monitoring
Difficulty Level: Moderate–Advanced
Estimated Repair Cost: €80–€450+
Last Updated: 9 December 2025

Real-World Example / Field Notes

A vehicle arrived with intermittent stalling and P0320 stored. Live data showed the RPM signal dropping to zero even though the engine continued spinning. The crankshaft position sensor wiring harness had a broken internal conductor caused by vibration. Repairing the wiring restored a clean RPM signal and the code disappeared.

Another case involved a distributor-equipped engine with hard starting. The pickup coil inside the distributor was cracked and failed intermittently when warm. Replacing the distributor assembly resolved the issue completely.

Symptoms of P0320 – Ignition/Distributor Engine Speed Input Circuit

No-start condition: The engine may crank but not fire.
Intermittent stalling: Loss of RPM signal shuts down spark and fuel.
Rough running: Incorrect timing due to unstable speed input.
Hard starting: RPM signal delay slows fuel delivery and spark.
Erratic tachometer: RPM needle may drop or bounce.
Check engine light: Often paired with CKP/CMP sensor codes.

Common Causes of P0320

Most Common Causes

Failed crankshaft position sensor (CKP)
Faulty camshaft position sensor (CMP)
Distributor pickup coil failure (if equipped)
Damaged or corroded CKP/CMP wiring and connectors
Incorrect air gap between sensor and tone wheel

Less Common Causes

Failed ignition control module (ICM)
Worn distributor shaft or internal bearing play
PCM not receiving RPM input due to internal fault
Loose or damaged reluctor ring/tone wheel
Aftermarket remote-start or alarm wiring interference

Diagnosis: Step-By-Step Guide

Diagnosing P0320 focuses on ensuring that the RPM signal from the CKP, CMP, or distributor is reaching the ECU correctly and consistently.

Tools You’ll Need

OBD-II scanner with live data, multimeter, oscilloscope (preferred), wiring diagrams, feeler gauges, and basic hand tools.

Check freeze-frame data: Note engine temperature and RPM when the code set.
Monitor live RPM data: RPM should display steadily during cranking and running.
Inspect crankshaft and camshaft sensors: Look for damage, loose mounting, or contamination.
Check wiring harness: Wiggle-test CKP/CMP harness while watching RPM data.
Test CKP/CMP with multimeter: Verify resistance and signal output.
Use oscilloscope if available: Check for clean square-wave or sine-wave signals.
Inspect distributor components: Check pickup coil, reluctor, and shaft play.
Inspect tone wheel: Verify no cracked or missing teeth.
Check for interference: Look for aftermarket wiring spliced into ignition circuits.
Test ignition control module: If signal is present but PCM does not receive proper timing input.

Pro Tip: Many intermittent P0320 issues are caused by heat-related CKP sensor failure—test the sensor both cold and warm for accurate results.

Possible Fixes & Repair Costs

Replace crankshaft position sensor: €40–€120
Replace camshaft position sensor: €40–€100
Replace distributor pickup coil or distributor assembly: €80–€250
Repair sensor wiring or connectors: €50–€150
Replace ignition control module (ICM): €80–€180
Replace PCM (rare): €200–€450+

Can I Still Drive With P0320?

Driving with P0320 is risky. The engine may suddenly stall without warning due to loss of RPM input. A complete no-start condition can occur at any time. If your vehicle is running inconsistently or stalling, do not continue driving until the issue is repaired.

Last updated: March 1, 2026

Key Takeaways

P0320 means the ECU is not receiving a valid engine speed signal.
CKP/CMP sensors and wiring are the most common causes.
Stalling and no-start conditions are likely if ignored.
Early diagnosis prevents sudden roadside breakdowns.

FAQ

Is P0320 caused by a bad crankshaft sensor?

Yes, the CKP sensor is the most common cause, especially if the engine stalls or won’t start.

Can a bad distributor cause P0320?

On distributor-equipped engines, a failing pickup coil or worn distributor shaft can trigger the code.

Will the car start with P0320?

Sometimes, but many vehicles will not start or may stall unpredictably.

Can wiring issues trigger P0320?

Absolutely. Damaged or corroded signal wires are a frequent cause of intermittent P0320 faults.

Is P0320 dangerous?

It can be. Loss of the engine speed signal may cause sudden stalling while driving.

P0320 – Ignition/Distributor Engine Speed Input Circuit