What the Job Is and What Is in the Price
The crank sensor reads a toothed ring on the crankshaft, flywheel, or harmonic balancer. Most rings have a missing tooth or two. That gap tells the computer where top dead center is. From the timing of the pulses, the computer knows engine speed down to a few rpm.
Every spark and every injector pulse is built from this signal. That is why a dead crank sensor usually means no start at all, and why a weak one causes stalling, misfires, or a tachometer that drops to zero while you drive.
A fair price includes scanning for codes, testing the sensor signal and wiring, swapping the sensor with a new O-ring, running a crank relearn if the car needs one, and a test drive. On easy engines the swap is short. On hard engines most of the cost is getting to it.
Why Prices Vary So Much
Where the sensor lives on your engine decides most of the price. Front mount sensors near the crank pulley can be done in half an hour. Sensors on the back of the block, above the starter, or in the bell housing can take one and a half to two hours because other parts come off first.
The relearn step adds time on some cars. Many GM, Ford, and some hybrid models want a crank variation relearn after the sensor is changed. Without it, the computer can set a misfire or crank code later. That needs a capable scan tool, which most shops and many mobile techs have.
Parts tier matters. Cheap sensors run $15 to $35 and work fine on some cars and fail fast on others. Quality and factory sensors run $50 to $160. On a part that can strand you, the better sensor is cheap insurance.
Dealers often add a full hour of diagnosis to a no start. Independent and mobile shops usually charge less for the same testing, and a mobile tech saves you the tow on a car that will not start.
Is It Really the Crank Sensor?
A crank no start has a dozen causes, and the crank sensor is only one of them. Before you buy the part, the tech should prove it.
The quickest check is the tachometer. If the tach needle does not move at all while you crank, the computer is not seeing engine speed. That points strongly at the crank sensor or its wiring. If the tach moves, look elsewhere first.
A scan tool can watch rpm while cranking. A scope can show the actual signal pattern. Either one beats guessing.
Wiring is a common culprit. The crank sensor harness often runs near the exhaust or the starter and can melt or rub through. A cracked plug or corroded pins cause the same symptoms as a bad sensor.
A damaged tone ring, a worn harmonic balancer that has slipped, or metal debris stuck to a magnetic sensor tip can also kill the signal. A new sensor will not fix any of those.
- Fuel pump not running or no fuel pressure
- Anti theft system blocking the start, often with a security light on
- Failed ignition coil pack or ignition module on older cars
- Melted or rubbed wiring near the exhaust or starter
- Damaged tone ring or slipped harmonic balancer
- Bad camshaft position sensor on engines that need both signals to start
What Usually Gets Done at the Same Time
Always put on the new O-ring and check the sensor tip for metal debris before installing. Debris on the old one is a clue that something inside the engine or transmission is shedding metal.
If the sensor is above the starter and the starter is original on a high mileage car, ask about doing the starter while it is apart. That only makes sense if the starter is already slow or noisy. Do not replace a good starter just because it is nearby.
If the wiring near the sensor is brittle, a pigtail repair is worth a few dollars more. Replacing the sensor and plugging it into a cracked connector is how you get a second tow.
Fuel system cleaning, a tune up, or a new cam sensor are not normal add-ons to this job. Ask for proof before you approve any of them.
Questions to Ask Before You Approve the Work
These questions tell you whether the shop has tested the problem or is guessing.
- Did the tach or scan tool show zero rpm while cranking?
- Did you check the wiring and plug, or only the code?
- Where is the sensor on my engine, and what has to come off to reach it?
- Does my car need a crank relearn, and is that in the price?
- What brand of sensor are you using?
- Is the tow or diagnostic fee credited toward the repair?
- What happens if the car still will not start after the new sensor?
Mobile Mechanic or Shop?
A crank sensor is one of the best jobs for a mobile mechanic, because the car often will not start and a tow costs $75 to $150 on its own. If the sensor is at the front of the engine or on the side of the block, a mobile tech can diagnose and fix it in your driveway.
Sensors that need the starter or exhaust removed, or that sit in the bell housing of a truck or diesel, are still doable on jack stands, but they take longer. Give the tech your year, make, and engine and ask where the sensor is before they come out.
How to Make the New One Last
A good crank sensor can last the life of the engine. Heat, oil, and broken wiring are what end them early.
Fix oil leaks near the sensor, keep the harness clipped away from the exhaust, and use a quality part. If a sensor fails again within a year, look hard at the wiring and the tone ring before buying a third one.
Signs you need this repair
- Engine cranks normally but will not start, and the tach needle does not move
- Engine stalls while driving, then restarts after it cools down
- Check engine light with codes from P0335 to P0339
- Tachometer drops to zero or jumps around while the engine is running
- Misfires, jerking, or surging at steady speed
- Hard starting that gets worse when the engine is hot
- Rough idle or vibration with no clear cause
Cost by vehicle type
| Vehicle | Typical range | Notes |
|---|---|---|
| Compact / economy car | $80 to $415 | Usually at the front of the engine near the crank pulley or on the side of the block, often reachable from below in under an hour. Parts are cheap. |
| Midsize sedan / small SUV | $85 to $440 | Four cylinders are usually easy. Several V6 sedans put the sensor on the back of the block or behind the transaxle, which can mean removing a heat shield or working from below. |
| Full-size truck / large SUV | $100 to $510 | Many V8 trucks mount the sensor on the side or back of the block, sometimes above the starter. Access is usually from under the truck and labor runs about an hour to an hour and a half. |
| Luxury / European | $120 to $620 | Several German engines mount the sensor at the back of the block near the transmission, and some need an exhaust or starter removal to reach. Factory sensors cost more, and many specialists stick with them for a clean signal. |
| Hybrid | $95 to $485 | Same sensor as the gas version of the engine. Some hybrids also need a scan tool relearn so the computer knows how the engine and motor line up after the swap. |
| Electric vehicle | Electric vehicles have no crankshaft, so there is no crank sensor. The motor has its own resolver or position sensor inside the drive unit. | |
| Diesel / heavy duty | $120 to $605 | A diesel will not start at all without this signal. Sensors sit low on the block or bell housing where grime and rust are common, so expect the top of the labor range and a pricier part. |
Ranges assume national-average labor rates ($95, $140/hr) and quality aftermarket parts.
Cost by state
State ranges reflect typical independent-shop labor rates for a midsize vehicle.
Common questions
How much does a crankshaft position sensor replacement cost?
Most drivers pay about $90 to $440 at an independent shop. Front mount sensors on small engines are near the bottom. Sensors buried behind the starter or bell housing on trucks and European cars are near the top.
Can I drive with a bad crankshaft position sensor?
It is not a good idea. The engine can shut off without warning, and you lose power steering and most of your brake assist when it does. If the car has stalled even once, get it fixed before you drive it in traffic.
Will a bad crank sensor always set a check engine light?
No. A sensor that dies completely can leave the car cranking with no code at all, because the computer never sees the engine turning. That is why a tech checks the tach or rpm reading while cranking.
Why does my car start when it is cold but not when it is hot?
That is a classic sign of a failing crank sensor. Heat opens up a crack in the sensor coil or wiring and kills the signal. When it cools, the crack closes and the car starts again until the next heat cycle.
Do I need to do a relearn after replacing the crank sensor?
Many GM, Ford, and some hybrid models need one, and others do not. The relearn teaches the computer the exact tooth spacing so it can detect misfires. Skipping it can set a code later, so ask the shop if your car needs it.
How much does a dealer charge for a crank sensor?
Dealers often land $100 to $250 above an independent shop. Most of that gap is a higher labor rate, a separate diagnostic charge, and factory parts. The repair itself is the same.
Can a bad crank sensor damage my engine?
It rarely causes damage inside the engine. The real danger is stalling in traffic. Misfires from a weak signal can also overheat the catalytic converter if you keep driving on them for a long time.
Related Repair Guides
More Engine Repair Costs
Sources and further reading
Primary sources behind this page. Federal safety, emissions and consumer-protection references, worth reading before you authorize any repair.
- Nevada DMV: On-Board Diagnostics testing How emissions programs read OBD codes and why a lit check engine light fails inspection.
- California Bureau of Automotive Repair Your rights on written estimates, approvals, and getting old parts back.
- fueleconomy.gov maintenance guide DOE and EPA guidance on how engine faults like misfires waste fuel.
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