P0336: crankshaft position sensor range/performance and the reluctor ring

There is an important distinction between the two most common crankshaft sensor codes, and it decides whether you are buying an inexpensive sensor or removing a gearbox.

P0335 — circuit malfunction. Usually no signal at all. P0336 — range/performance. A signal exists, but its pattern does not match what the ECU expects.

Related: P0335 crankshaft position sensor diagnostics.

What “range/performance” means physically

The crankshaft signal is a series of pulses from a toothed wheel, with a deliberate gap or irregularity that marks a reference position. The ECU counts teeth and finds that reference to know exactly where the crank is.

P0336 sets when the count is wrong: teeth missing where there should be teeth, an extra pulse, or a reference gap that appears in the wrong place.

That is a pattern problem, and a pattern problem is more often the wheel than the sensor.

Causes ordered by what you should check

1. Air gap

The sensor mounts at a specified distance from the ring. A mounting bolt not fully tightened, debris trapped between sensor and ring, or a sensor fitted without its spacer all change the gap.

Too far and pulses weaken; too close and they distort. Both produce a pattern the ECU rejects.

Check the mounting before anything else. It is free.

2. Debris on the ring

Metallic swarf from a clutch or a worn component sticks to the ring — the sensor’s magnetic field attracts it. The extra material reads as extra teeth.

This is a genuinely common finding on engines where the ring sits inside the bellhousing.

3. Damaged or cracked reluctor ring

Teeth chipped by a slipping tool during previous work, or a ring cracked from age. On engines where the ring is part of the flywheel or the crank pulley, this is where the repair becomes expensive.

4. The sensor

Degraded sensors produce weak or noisy signals. Still common, still cheap, but check items 1 to 3 first — the code is telling you it received something.

5. Wiring and shielding

The signal is low level and the cable is shielded. A previous repair that ignored the shield produces exactly this kind of intermittent pattern fault.

6. Crankshaft end float

Excessive end float lets the crank move axially, changing the air gap dynamically. Rare, serious, and worth knowing exists — it usually arrives with other symptoms.

The symptom set

• Intermittent stalling, sometimes with an immediate restart: engine stalls while driving.
• Long cranking before it fires: engine cranks but won’t fire.
• Misfire codes with no misfire — the ECU misjudges cylinder position and misfire detection depends on this signal being clean.
• Correlation codes alongside, because crank/cam correlation is calculated from this signal: P0016 crank-cam correlation.

That third point is worth emphasising. Random misfire codes with no rough running are frequently a crank signal problem, not an ignition problem. People replace coils and plugs for this.

After a clutch or gearbox job

If P0336 appeared after clutch, flywheel or gearbox work, treat the timing as evidence rather than coincidence. Likely causes:

• Swarf on the ring from clutch material.
• The sensor disturbed or refitted without its spacer.
• A wrong flywheel fitted — a dual mass and a solid conversion can have different tooth patterns.
• The harness pinched during reassembly.

Reading the data

Log engine RPM and look at the shape, not the number.

Behaviour	Meaning
Smooth and matching the tachometer	Signal healthy
Spikes or dropouts at steady RPM	Pattern fault — ring or gap
Drops to zero while the engine runs	Signal loss
Reads high at cranking	Noise being counted as teeth

If misfire codes appear at the same instant as RPM spikes, they are the same fault.

Reading live data graphs properly.

Where to start

1. Read all codes — correlation and misfire codes alongside are informative.
2. Note whether it followed recent work on the clutch or gearbox.
3. Inspect the sensor mounting and its air gap.
4. Look for debris on the ring where access allows.
5. Check the harness and shield.
6. Replace the sensor with an OE-quality part.
7. If it persists, the ring itself needs inspection — and that is where cost enters.

This check needs no workshop — an ELM327 adapter and the free tier of the app cover it. Log RPM alongside misfire counters. Spikes that line up between the two are one fault wearing two disguises.