P0322 Code: Ignition/Distributor Engine Speed Input Circuit No Signal

What the P0322 code means

To fire the injectors and the spark at exactly the right moment, the computer has to know how fast the engine is turning and where it is in its rotation. On most vehicles that signal comes from the crankshaft position sensor. On others, mainly systems with a distributor, it comes from the ignition module itself.

The P0322 code is stored when that signal does not arrive at all. It is not that the signal is wrong or intermittent: it simply does not exist.

The consequence is immediate and leaves no room for nuance. Without the engine speed, the computer cannot decide when to open the injectors or when to fire the spark, so the engine will not start. If the signal is lost while driving, the engine stalls suddenly.

Diagnosis therefore points at the sensor, its wiring and its reluctor wheel. And there is one check worth doing first because it is free: the tachometer on the dash. If it does not move while you crank the engine, that confirms the signal is not arriving.

It helps to understand why the engine cannot even try to start without this signal. The computer has no other way of knowing where the pistons are or how fast they are turning, and without that it cannot decide the instant of the spark or of the injection. It is not that the engine runs badly: the system has no way to begin. That is why the typical symptom is so categorical, an engine that turns over on the starter with no sign at all of wanting to fire.

There is a pattern worth knowing that repeats a lot with this code and misleads many shops. A sensor that fails from thermal expansion works perfectly when cold and stops generating a signal once the engine reaches temperature. The vehicle stalls, the driver waits half an hour, and it starts again without trouble.

In that scenario, any measurement taken with the engine cold will come out fine and the diagnosis will be closed wrongly. The only way to confirm it is to reproduce the condition: let the engine reach temperature, or heat the area around the sensor with a heat gun while you watch the signal.

P0322 code symptoms

• The engine cranks but does not start.
• Sudden stall while driving.
• Tachometer stuck at zero while cranking.
• Check engine light on.
• No spark and no injector pulse.
• The engine starts sometimes and not others.
• May appear together with crankshaft sensor codes.
• The engine stalls after a while on the road and starts again about half an hour later.

Likely causes of the P0322 code

1. Failed crankshaft position sensor. The most frequent cause.
2. Defective ignition module on systems with a distributor.
3. Signal wire cut or shorted to ground.
4. Connector that is corroded, loose or has backed-out pins.
5. Crankshaft reluctor wheel damaged or with broken teeth.
6. Metal shavings stuck to the sensor tip.
7. Missing power supply on Hall effect sensors.
8. Open circuit ground.
9. Distributor with excessive play on the systems that have one.
10. Sensor that fails from thermal expansion, fine when cold and useless once the engine is hot.

How to diagnose the P0322 code step by step

1. Watch the tachometer while cranking. If it does not move, that confirms the signal is not arriving. It is the quickest check.
2. Check for spark and injector pulse while cranking.
3. Remove the sensor and clean its tip of metal shavings.
4. Measure the sensor resistance if it is an inductive type, or check its power supply if it is a Hall effect type.
5. Verify the continuity of the signal wire and its ground back to the computer.
6. Watch the signal with an oscilloscope while cranking. It should be clean and regular.
7. Inspect the reluctor wheel for damaged teeth or play.
8. Check the distributor shaft for play on the systems that have one.
9. Heat the area around the sensor with a heat gun while you watch the signal, if the fault only shows up with a hot engine.

How to fix the P0322 code

• Clean the sensor tip and its mounting bore before you consider replacing anything.
• Replace the crankshaft position sensor if it does not generate a signal while cranking.
• Replace the ignition module on distributor systems when the diagnosis points to it.
• Repair the signal wire that is cut or shorted to ground.
• Clean or replace the connector and protect it with dielectric grease.
• Correct or replace the damaged reluctor wheel.
• Restore the circuit ground down to bare metal.
• Replace the distributor if its shaft has excessive play.
• Replace the sensor if it stops generating a signal when heated, even though its cold measurements come out fine.

After the repair, clear the P0322 code and confirm that the tachometer moves as soon as the engine starts to turn.

Technical reference data

• Inductive sensors: typical resistance between 200 and 1,500 ohms, with no external power supply.
• Hall effect sensors: 5 or 12 volt supply and a square wave signal.
• Usual air gap between the sensor and the reluctor wheel: 0.5 to 1.5 mm (about 0.020 to 0.060 in).
• Usual crankshaft reluctor wheel: 58 teeth plus a reference gap.
• Without this signal there is no spark and no injection: the engine cannot start.
• A tachometer that stays still while cranking confirms the signal is missing.
• A sensor that fails from thermal expansion measures fine when cold and stops generating a signal when hot.

Brand-specific notes

The tachometer is the cheapest diagnostic tool there is for this code. If it does not move while the engine turns on the starter, the signal is not arriving and the diagnosis goes straight to the sensor and its circuit.

Many crankshaft sensors fail when hot and recover once they cool down. If the vehicle stalls after a while on the road and starts again half an hour later, that pattern points to the sensor even if the cold measurements come out fine.

Frequently asked questions about P0322