P0322

What does P0322 mean?

P0322 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Ignition/Distributor Engine Speed Input Circuit Low.

This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.

Symptoms commonly associated with this code

Symptoms that drivers often report alongside this code. Not all may apply to every case:

• • Engine turns over on the starter but won't catch, or fires up then dies a second later
• • Engine warning light on, sometimes with no other obvious problem
• • Random stalling while driving or coming to a stop at a junction
• • Rough idle and misfiring, the engine hunting and stumbling
• • Flat spots and hesitation when you put your foot down
• • Intermittent no-start that comes and goes with no pattern, classic sign of a wiring or connector fault rather than a dead sensor

Possible causes

Causes commonly associated with P0322, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.

1. 1. Crankshaft position sensor failed or on its way out, by far the usual offender. Heat soak near the engine block kills these over time
2. 2. Damaged or corroded wiring and connectors in the sensor circuit, often where the loom runs close to hot exhaust components
3. 3. Dirty or loose plug at the sensor itself, a bit of oil or muck on the pins can drop the signal enough to trip the code
4. 4. Camshaft sensor or distributor pick-up playing up on older vehicles that still run one
5. 5. Weak battery or charging fault leaving the sensor without enough voltage to produce a recognisable signal
6. 6. Metal swarf or debris stuck to the reluctor ring or the sensor face, scrambling the readings
7. 7. ECU fault, rare but not impossible if everything else checks out clean

How mechanics typically diagnose

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.

1. 1. Plug in a scanner and read every stored code, not just this one. Other crank and cam sensor codes (P0335, P0340) point you straight at the circuit and tell you how many sensors are involved
2. 2. Get under the car and eyeball the crank sensor connector and harness. You're looking for chafed insulation, green corrosion on the pins, melted plastic near the exhaust, or a plug that isn't fully seated
3. 3. Check battery and charging voltage. You want around 12.6V resting and above 13.8V with the engine running, because a tired battery can starve the sensor of a clean signal
4. 4. Put a multimeter across the sensor supply with the ignition on. Hall-effect types want roughly 5V on the feed. No supply means the fault is upstream in the wiring, not the sensor
5. 5. Hook up an oscilloscope and crank the engine. A healthy sensor gives a steady square wave around 2-5V. A flat line or ragged trace while everything else is good confirms the sensor
6. 6. Only fit a new crank sensor once the wiring and supply have passed. Clear the codes and road test, because swapping the sensor without finding a chafed wire just gets you the same fault back

Common questions about P0322