OBD-II Code P0336 — What It Means & How to Fix It

What Does This Error Mean?

P0336 means the crankshaft position sensor is generating a signal, but it is intermittent or out of the expected range. Unlike P0335 where the signal is completely missing, P0336 means the signal exists but is erratic or noisy. The ECM receives some data but cannot fully trust it. Common causes are a failing sensor, a damaged reluctor ring tooth, or wiring interference. Symptoms include rough running, misfires, and hard starting — especially when the engine is hot.

Affected Models

All vehicles 1996+
Common in Chevrolet Cobalt
Common in Pontiac G5
Common in Saturn Ion
Common in Ford vehicles with 4.6L engine

Common Causes

Crankshaft position sensor beginning to fail — generating a weak or intermittent signal
One or more damaged or broken teeth on the reluctor ring causing signal dropouts
Metal shavings or engine debris partially blocking the gap between the sensor and reluctor ring
Damaged wiring or loose connector causing intermittent signal loss
Excessive crankshaft end play or worn main bearings affecting reluctor ring alignment

How to Fix It

Inspect the crankshaft position sensor and its wiring harness first. Check the connector for corrosion or loose fit. Inspect the wire routing for damage from heat, abrasion, or contact with moving parts. Fix any wiring issues found.

An intermittent signal (range/performance code) is often caused by a bad connection rather than a completely failed sensor. A wiggle test on the wiring during a test drive can reveal the issue.
Check the air gap between the sensor tip and the reluctor ring. The gap should be very small — typically 0.020 to 0.050 inches. A sensor that has shifted or a reluctor ring that has moved can cause range errors.

Some CKP sensors are adjustable — a shim kit may be available for your vehicle. Others are fixed-gap designs. Check your vehicle's service information for the correct specification.
Use a scan tool with live data to watch the RPM signal while cranking the engine. A healthy CKP sensor should produce a smooth, consistent RPM reading. A signal that jumps erratically or drops to zero momentarily while cranking points to sensor or reluctor ring issues.

If the RPM signal disappears intermittently, pay attention to whether it coincides with specific conditions — like a hot engine or certain RPM ranges. This pattern helps identify whether the sensor or reluctor ring is the problem.
Replace the crankshaft position sensor as the most likely and least expensive fix. The sensor itself fails more often than the reluctor ring. Clear the code and test drive thoroughly, including getting the engine fully hot.

Some CKP sensor failures only show up when the sensor is hot. If the car runs fine cold but the code returns after full warm-up, the sensor is thermally failing — a very common failure mode.
If the code returns after sensor replacement, have a mechanic inspect the reluctor ring for damaged or missing teeth. This requires a visual inspection with the sensor removed and a light shined into the sensor bore while the crankshaft is rotated.

Reluctor ring inspection does not usually require engine disassembly — just sensor removal and a careful look with a flashlight. A missing tooth will be obvious.

When to Call a Professional

P0336 often leads to getting worse if not repaired — it can progress into P0335 (total signal loss). A crankshaft position sensor replacement costs $150-$350 parts and labor. If reluctor ring damage is suspected, a mechanic needs to perform an internal inspection. Reluctance ring damage on some engines is a known issue — ask a mechanic if your vehicle has a known pattern failure. Don't put this repair off if the engine is misfiring or stalling intermittently.

Frequently Asked Questions

What is the difference between P0335 and P0336?

P0335 means the ECM is getting no signal at all from the crankshaft sensor. P0336 means the ECM is getting a signal, but it is erratic or out of its expected range. P0335 usually causes a no-start or immediate stall. P0336 usually causes intermittent problems — hard hot starts, random misfires, or rough running. Both often point to the same sensor or wiring, but P0336 can also indicate reluctor ring damage.

Why does P0336 often show up when the engine is hot?

Sensors and their internal components expand when hot. A sensor that is starting to fail may work fine when cold but fail when it expands with heat. This is called a thermal failure and is very common in crankshaft position sensors. If your car starts fine cold, runs for 20-30 minutes, and then develops a rough idle or stall — suspect a thermally failing CKP sensor.

Can a bad crankshaft sensor cause misfires?

Yes, absolutely. The ECM uses the CKP signal to determine exact timing for spark and fuel injection. An erratic signal causes the ECM to fire the wrong cylinder at the wrong time. This creates misfires, rough running, and poor power. If you have both P0336 and misfire codes (P0300 series), the CKP sensor is almost certainly the cause of both.