Ignition/Distributor Engine Speed Input Circuit
What it means
The engine computer is not receiving a valid engine speed signal from the ignition system, whether from a pickup inside the distributor on older cars or from the crankshaft position sensor, depending on the design. Without this signal the computer cannot time spark and fuel, so the engine may stumble, stall or not start.
Symptoms5
- Hard starting, or the engine cranks but does not start.
- Sudden stalling while driving or when stopping.
- Stumbling or misfires.
- Tachometer flickers or drops to zero.
- Check engine light on.
Possible causes6
- Failed distributor pickup or crankshaft position (CKP) sensor.
- Damaged or corroded wiring or connector between the sensor and the engine computer.
- Faulty ignition module on systems that pass the signal through it.
- Poor engine or ignition system ground.
- Damaged tone ring or metal debris stuck to a magnetic sensor.
- Engine computer fault (rare).
How to diagnose6
- Use the service manual to find the speed signal source on this car: a distributor pickup or the CKP sensor.
- Watch engine RPM on a scan tool while cranking; no reading confirms the signal is lost.
- Inspect the connector and wiring for corrosion, chafing or heat damage, and wiggle them with the engine running to find an intermittent fault.
- Measure the sensor signal with a meter or oscilloscope and compare it with the manufacturer specification.
- Check the grounds and the ignition module if fitted.
- Remove the sensor and inspect its tip and the tone ring for debris or damage.
How to fix5
- Clean the connector and repair damaged wiring or grounds.
- Clean metal debris off the sensor tip if that weakened the signal.
- Replace the CKP sensor or distributor pickup if it is proven faulty.
- Replace the ignition module, or the whole distributor on cars where the pickup is part of it.
- Clear the codes, start the engine, road test and confirm the code does not return.
Repair cost
In Saudi riyals; the highlighted part is the expected range for this fault.
The cost is low for a connector or wire, rises with a new sensor, and reaches the top of the range if an ignition module or complete distributor is needed.
Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026
Frequently asked questions
Can I drive with code P0320?
Only very carefully and for a short distance, because the engine may stall suddenly while moving. If it keeps stalling, have the car towed to a shop.
How is this code related to the crankshaft sensor?
On many modern cars the CKP sensor is the source of the speed signal, so this code can appear with P0335 and share the same fix.
This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.
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