# P0335: Crankshaft Position Sensor "A" Circuit **Verdict:** Drive to a shop this week Engine sensors - Generic OBD-II code, applies to all gasoline cars and light trucks sold in the US since 1996. - **Typical cost:** $150-$600 - **Urgency:** This week - **Most likely:** Failed crankshaft position sensor - **DIY?:** Sometimes, if easy to reach ## Quick answer P0335 means the engine computer is not getting a usable signal from the crankshaft position sensor, which tells it how fast the engine is turning and where the pistons are. The engine needs this signal to time spark and fuel, so a bad sensor can cause stalling or a no-start. The usual fix is a new sensor or a wiring repair. ## What does P0335 mean? The crankshaft position sensor reads a toothed reluctor ring on the crankshaft, harmonic balancer or flywheel. Each passing tooth produces a pulse, and a gap where teeth are missing marks a reference point. From those pulses the engine computer calculates engine speed and piston position, which it needs to time every spark and injector pulse. It also uses tiny changes in crank speed to detect misfires. P0335 is a circuit code for crank sensor "A", the first or only crank sensor. The computer sets it when it sees no crank signal, or an erratic one, while other signals such as the camshaft sensor show the engine is turning. Because the engine depends on this signal, the code can set the first time the fault happens. Sensors come in two types: two-wire magnetic sensors that generate their own voltage, and three-wire Hall-effect sensors fed a reference voltage by the computer. ## What are the symptoms of P0335? - Engine cranks but will not start - Engine stalls without warning, often once it is warm - Tachometer drops to zero or jumps around while driving - Rough running or misfires - Check engine light on ## What causes P0335? Ranked from most to least likely. Check them in this order: the cheap, common causes first. 1. **Failed crankshaft position sensor** (most common). The sensor's electronics and windings break down with years of heat cycles, and a failing sensor often cuts out once the engine is fully warm, then works again after cooling. That stall-when-hot, restart-when-cool pattern points strongly to the sensor. It can happen at any mileage but is more common on older vehicles. A scope on the signal confirms it. 2. **Damaged wiring or loose connector** (common). The sensor sits low on the engine, near the crank pulley, bell housing or oil pan, where its wiring can rub, crack from heat or soak in oil. A loose connector can drop the signal over bumps. Look for chafed insulation, oil in the connector and bent pins, then wiggle-test the harness while watching rpm on a scan tool. 3. **Damaged reluctor (tone) ring** (less common). The sensor reads teeth on a reluctor ring attached to the crankshaft, harmonic balancer or flywheel. Missing or bent teeth, a slipped balancer outer ring, or a ring damaged during clutch or engine work gives a bad signal even with a new sensor. An irregular scope pattern, or a code that returns right after a new sensor, points here. 4. **Oil-soaked or debris-covered sensor tip** (less common). Magnetic crank sensors attract fine metal particles from engine wear or clutch dust, and the buildup can distort or weaken the signal. An oil-soaked tip from a nearby leak does the same. Cleaning the tip sometimes restores the signal, but a new sensor plus fixing the oil leak is the more reliable repair, especially on high-mileage engines. 5. **Engine computer fault** (rare). The engine computer powers Hall-effect sensors with a reference voltage and processes their signal. An internal fault, water intrusion or a shorted sensor that damaged the 5-volt circuit can stop it from reading the crank signal. Because this is rare, a shop confirms good sensor output and wiring at the computer connector before replacing or reprogramming the computer. ## How do you diagnose P0335? 1. Watch the tachometer while cranking. If it stays at zero on a no-start, the crank signal is likely missing. 2. Check for related codes such as P0340 (camshaft sensor), which can point to wiring or timing problems. 3. Inspect the crankshaft sensor connector and wiring for oil, damage, or looseness. 4. Test the sensor's output with a scan tool RPM reading or a scope while cranking, and check power and ground at the connector. ## How do you fix P0335, and what does it cost? | Fix | Typical cost | What it involves | | --- | --- | --- | | Replace crankshaft position sensor | $150-$400 | Most sensors are reachable from under the car. Some require removing other parts, raising labor. | | Repair sensor wiring or connector | $120-$350 | Fixes a chafed wire or corroded plug. | | Repair damaged reluctor ring | $600-$2,000 | Rare. Depending on the engine, it may mean replacing a harmonic balancer or flywheel, or internal engine work. | ## Is it safe to drive with P0335? > **Drive to a shop this week.** Drive only if you must. A failing crankshaft sensor can stall the engine in traffic with no warning, which is dangerous, so get it repaired before long trips. ## Will P0335 fail an emissions test? With P0335 stored and the light on, the car fails an OBD-based emissions test. A faulty crank signal can also keep the misfire monitor from working properly, because the computer relies on crank speed to detect misfires. After the repair, clear the code, complete any crank relearn your vehicle needs, and drive several days so the readiness monitors report complete. ## After the repair: clearing P0335 Clear the code, then start the engine several times both cold and fully warm, since many crank sensors fail only when hot. Some vehicles, including many GM models, need a crankshaft position variation relearn with a scan tool after the sensor is replaced, or misfire detection may be inaccurate. If stalling and the code do not return within a week, the fix worked. ## How to prevent P0335 - Fix oil leaks near the crankshaft sensor, such as a leaking front or rear crankshaft seal. - Keep the sensor connector clipped in place and its wiring away from exhaust and moving parts. - Buy a quality replacement sensor; poor-quality parts can bring the code straight back. - Have a stall-when-warm pattern checked early, before it strands you in traffic. ## Codes often seen with P0335 - [P0340](/codes/p0340): Camshaft Position Sensor "A" Circuit (Bank 1 or Single Sensor) - [P0300](/codes/p0300): Random/Multiple Cylinder Misfire Detected - [P0016](/codes/p0016): Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor A) ## Frequently asked questions ### Can I drive with a P0335 code? It is risky, because the engine can stall suddenly when the sensor drops out, and power steering and brake assist get harder without the engine running. If the car is running fine, drive it straight to a shop, avoid highways if you can, and do not plan long trips. ### Why does my car stall when warm and restart after cooling down? A failing crankshaft position sensor is the classic cause of this pattern. The sensor's electronics fail when hot and recover once they cool, which is why the problem seems to come and go. A shop can confirm it by watching the crank signal on a scope while the engine is hot. ### How much does it cost to replace a crankshaft position sensor? Most independent shops charge $150 to $400 including the part. It costs more on engines where the sensor is buried behind other components or reached only after removing a starter or heat shield. Wiring repairs run $120 to $350, and rare reluctor ring damage costs far more. ### Do I need to relearn anything after replacing the crank sensor? Some vehicles, including many GM models, need a crankshaft position variation relearn with a scan tool after replacement. Without it, misfire detection can be inaccurate and a misfire or crank code may return. Ask the shop whether your model needs this step before you leave. ### Will a car start with a bad crankshaft position sensor? Often it will not. With no crank signal, the computer cannot time spark or fuel, so the engine cranks but never fires. A few engines can start using the camshaft signal as a backup, but they usually run poorly. A tachometer that stays at zero while cranking is a strong clue. ### Where is the crankshaft position sensor? It is usually low on the engine: near the crankshaft pulley at the front, on the side of the block, or at the back near the transmission bell housing, where it reads the flywheel. Location varies by engine, so check service information. Many are easiest to reach from under the car. ### Can a bad crank sensor cause a misfire? Yes, an erratic crank signal can confuse the computer's timing and misfire detection, causing rough running or false misfire codes. If misfire codes appear on several cylinders along with P0335, check the crank sensor and its wiring before replacing spark plugs or ignition coils. ### What is the difference between P0335 and P0340? P0335 is a crankshaft position sensor circuit problem, while P0340 is a camshaft position sensor circuit problem. The crank sensor reports engine speed and piston position; the cam sensor reports which stroke each cylinder is on. Both together suggest shared wiring, a power supply fault or a timing problem. ### Can I replace a crankshaft position sensor myself? Sometimes, if it is easy to reach and held by one bolt. Disconnect the battery, unplug the sensor, remove the bolt and install a quality replacement with a new O-ring if supplied. Some sensors need an air gap set or a scan-tool relearn afterward, so check service information first. ### Will P0335 pass inspection? No, P0335 with the check engine light on fails an OBD-based emissions inspection. A faulty crank signal may also stop the misfire monitor from working properly. After the repair, clear the code, perform any required relearn and drive normally until the readiness monitors complete before testing. ## Sources - [SAE J2012: Diagnostic Trouble Code Definitions](https://www.sae.org/standards/content/j2012_201812/) ## Other engine sensors codes - [P0325 Knock Sensor 1 Circuit (Bank 1 or Single Sensor)](https://diagxcar.com/codes/p0325) - [P0326 Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor)](https://diagxcar.com/codes/p0326) - [P0327 Knock Sensor 1 Circuit Low (Bank 1 or Single Sensor)](https://diagxcar.com/codes/p0327) - [P0332 Knock Sensor 2 Circuit Low (Bank 2)](https://diagxcar.com/codes/p0332) - [P0336 Crankshaft Position Sensor "A" Circuit Range/Performance](https://diagxcar.com/codes/p0336) - [P0339 Crankshaft Position Sensor "A" Circuit Intermittent](https://diagxcar.com/codes/p0339) - [P0340 Camshaft Position Sensor "A" Circuit (Bank 1 or Single Sensor)](https://diagxcar.com/codes/p0340) - [P0341 Camshaft Position Sensor "A" Circuit Range/Performance (Bank 1 or Single Sensor)](https://diagxcar.com/codes/p0341) - [P0344 Camshaft Position Sensor "A" Circuit Intermittent (Bank 1 or Single Sensor)](https://diagxcar.com/codes/p0344) - [P0345 Camshaft Position Sensor "A" Circuit (Bank 2)](https://diagxcar.com/codes/p0345) - [P0016 Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor A)](https://diagxcar.com/codes/p0016) - [P0017 Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor B)](https://diagxcar.com/codes/p0017) - [P0018 Crankshaft Position - Camshaft Position Correlation (Bank 2 Sensor A)](https://diagxcar.com/codes/p0018) - [P0019 Crankshaft Position - Camshaft Position Correlation (Bank 2 Sensor B)](https://diagxcar.com/codes/p0019) ## Symptoms - [Why does my car crank but not start?](https://diagxcar.com/symptoms/car-cranks-but-wont-start) - [Why does my car stall while driving?](https://diagxcar.com/symptoms/car-stalls-while-driving) - [Why won't my car start?](https://diagxcar.com/symptoms/car-wont-start) ## Repair costs - [Crankshaft position sensor replacement cost](https://diagxcar.com/cost/crankshaft-position-sensor-replacement) - [Timing belt replacement cost](https://diagxcar.com/cost/timing-belt-replacement) --- Source page: https://diagxcar.com/codes/p0335 Updated: 2026-11-03 General information, not a substitute for a qualified mechanic.