P0335 Code: Crankshaft Position Sensor A Circuit Malfunction
The engine computer lost the crankshaft position signal. Expect stalling or a crank-no-start.
Stop driving
If the engine has stalled or cut out even once, don't drive it in traffic or on the highway. A dead engine means heavy steering and only a few assisted brake applications. If it won't start, have it towed. If it runs smoothly, a short, low-speed trip straight to a shop is the most you should risk.
At a glance
Severity: High
- Meaning
- Crankshaft Position Sensor A Circuit Malfunction
- System
- Ignition & Misfire · Powertrain
- Safe to drive?
- With caution
- Typical repair cost
- $50–$900
- DIY difficulty
- Moderate
The crankshaft position sensor reads a toothed tone ring on the crankshaft, harmonic balancer or flywheel. It gives the engine computer its most important input: exactly where the crank is and how fast it is turning. Spark timing, injector timing and misfire detection all depend on it. P0335 sets when the computer gets no signal, or an implausible one, from sensor A while the engine is cranking or running. Many engines won't start at all without this signal. Others limp along using the camshaft sensor as a backup but can stall with no warning, often once the engine is hot.
How to read P0335
- P Powertrain
- 0 Generic (SAE)
- 3 Ignition / misfire
- 35 Specific fault
Symptoms
- Engine cranks normally but won't start
- Stalling while driving or at a stop, often when fully warmed up, then restarting after it cools
- Tachometer drops to zero or jumps while the engine is running
- Rough running, misfires or hesitation
- Check-engine light on, sometimes with P0340 or misfire codes
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Failed crankshaft position sensor, often breaking down internally when hot
- Chafed, broken or oil-soaked wiring or connector at the sensor
- Damaged, loose or dirty tone ring (slipped balancer ring, missing teeth, metal debris on a magnetic sensor tip)
- Low battery voltage or poor engine grounds weakening the signal while cranking
- Shorted 5-volt reference shared with another sensor pulling the crank sensor supply down
- Sensor not fully seated, or wrong air gap after previous work
- Engine computer fault
Diagnosis step by step
Watch rpm on a scan tool while cranking
Connect a scanner and watch engine rpm while someone cranks the engine. A healthy system shows roughly 150–300 rpm while cranking. Zero rpm while the engine is clearly turning over means the computer isn't receiving a crank signal, which confirms the code.
Tools: OBD-II scanner
Check battery and cranking voltage
Measure battery voltage while cranking. If it drops below about 9.6 volts, the sensor signal and the computer can drop out. Fix a weak battery or bad cable before condemning the sensor, and check for P0562 as well.
Tools: Multimeter
Inspect the sensor wiring and connector
Depending on the engine, the sensor may sit at the front near the balancer, on the side of the block or at the rear by the flywheel. Look for melted insulation near the exhaust, a connector full of oil, broken locks or pulled terminals.
Tools: Flashlight
Test the sensor by type
A two-wire magnetic sensor should show a resistance within spec and produce an AC voltage while cranking. A three-wire Hall sensor needs a steady reference voltage (usually 5 volts, sometimes 12), a good ground, and a signal that switches on and off as the engine turns. Test the supply and ground first, because they are the most often overlooked.
Tools: Multimeter
Pull the sensor and inspect the tip and tone ring
Look for metal shavings stuck to a magnetic tip and for rubbing marks, which mean the ring or crank is out of position. Through the sensor hole, rotate the engine by hand and check the ring for missing or bent teeth. On balancer-mounted rings, look for a ring that has slipped on its rubber.
Tools: Flashlight
Replace with a quality sensor and do any relearn
Crank sensors are an area where cheap parts often fail quickly, so an OE-grade sensor is worth the money. After installation, some makes require a crankshaft position variation relearn with a capable scan tool so misfire detection works correctly.
Tools: OBD-II scanner
Where the parts are
- 1Ignition coil
- 2Spark plug
- 3Fuel injector
- 4Camshaft sensor
- 5Crankshaft sensor
- 6Engine computer (ECM)
- 7Intake manifold
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Replace crankshaft position sensor (easy access) | Yes | $150–$350 |
| Replace crankshaft position sensor (behind starter, under intake or transmission-side) | No | $300–$650 |
| Repair sensor wiring or connector | No | $100–$350 |
| Replace harmonic balancer or damaged tone ring | No | $300–$900 |
| Crankshaft position variation relearn (scan tool) | No | $50–$150 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Notes by brand
Nissan
Early-2000s Nissan models with the 2.5L QR25DE and 3.5L VQ35DE engines (Altima, Sentra, Maxima and others) are known for crankshaft and camshaft position sensor failures that cause sudden stalling. Some of these vehicles were covered by a recall, so run your VIN through NHTSA's recall lookup before paying for sensors.
Chevrolet
On many GM engines, the computer has to learn crankshaft position variation after a crank sensor, crankshaft or balancer replacement. Without that relearn, misfire detection may not work correctly and a relearn code can set, so make sure the shop or your scan tool can perform it.
Emissions / smog test impact
Will fail
If the car runs well enough to reach the test, a stored P0335 with the check-engine light on fails an OBD smog inspection. The misfire monitor relies on this sensor, so readiness status may not be complete until it has been fixed and driven.
Frequently asked questions
My engine cranks but won't start. Is it the crank sensor?
It's one of the top suspects, especially if P0335 is stored and the scan tool shows zero rpm while cranking. Other no-start causes, such as no fuel pressure, a failed fuel pump relay or immobilizer problems, usually show normal cranking rpm, so that one reading narrows it down quickly.
Why does it only stall when the engine is hot?
Many failing crank sensors develop internal cracks that open up as they heat and expand. The signal drops out, the engine dies, and after 20–30 minutes of cooling it restarts. That pattern points strongly at the sensor itself.
Is an aftermarket crank sensor okay?
Quality varies widely. Cheap sensors are a common reason for a repeat failure or a code that comes back within weeks. For a part that can leave you stranded, an OE or OE-supplier sensor is worth the extra cost.
Will the engine run on the camshaft sensor alone?
Some engines can, in a backup mode with reduced performance. Most need the crank signal to start or to stay running reliably. Don't count on it.