P0337 code: Crankshaft Position Sensor A Circuit Low
P0337 means crankshaft Position Sensor A Circuit Low. The code says where to look, not what failed — the fix depends on which cause your car actually has.
What P0337 means
Every spark and injection event is timed off the crankshaft position sensor, the computer's master reference for where the crank is and how fast it's spinning so spark and fuel land at the right instant. P0337 means the signal from that sensor is reading LOW — stuck at or below its minimum expected level — as opposed to P0338, the same circuit reading high. Typical causes are a failed sensor, a wiring short to ground, a corroded or loose connector, or a damaged reluctor (tone) ring giving a weak signal; an incorrect sensor air gap or metal debris on the sensor tip can also weaken it. This is stalling and no-start territory: when the crank signal drops out the engine dies or won't fire, sometimes intermittently and without warning, so treat it promptly.
P0337 symptoms
- Engine cranks but won't start, or starts hard
- Sudden stalling, sometimes with no warning
- Intermittent cutting out or rough running
- Tachometer dropping to zero or behaving erratically
- Check-engine light
What it costs to fix P0337
Typical range: $100–$400 · about ~0.5–1.5 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| Crankshaft position sensor | $30–$150 | ~0.5–1.5 hrs |
| Wiring / connector repair | $10–$120 | ~0.5–1.5 hrs |
The sensor is a cheap part; the cost is mostly labor and depends on where it lives — some are right up front by the crank pulley, others hide behind the starter or transmission bellhousing. A damaged reluctor ring is a much bigger job and varies too much to quote.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0337 for my exact vehicle →
How to fix P0337
Moderate — doable at home with common tools and patience
- Treat it as a stall risk and read every stored code
Losing the crank signal cuts spark and fuel at once, so P0337 can stall the engine in traffic or cause a crank-no-start; if it has quit already, diagnose it where it sits or tow it. Then look for other circuit-low codes — cam sensor, MAP, or throttle position — logged at the same time, because they may share a 5-volt reference with the crank sensor.
- Find what's dragging a shared reference down
On three-wire Hall-type sensors, measure the reference pin with the key on; it's commonly 5 volts, on some designs battery voltage. If it's low and other sensors on the same reference also set codes, unplug them one at a time — the reference jumping back up when one is disconnected identifies a shorted sensor or harness branch, not the crank sensor.
- Check the signal wire for a short to ground
With the sensor unplugged and the key on, a Hall-type signal pin on most designs should sit at the computer's pull-up voltage; if it reads near zero, the wire is grounded somewhere along its run. On two-wire magnetic sensors, measure the coil resistance against spec and confirm neither wire has continuity to the block.
- Pull the sensor and check the tip, gap, and tone ring
A weak signal reads as circuit low too. Look for metal swarf or sludge on the tip, a cracked body, or a missing spacer, and confirm the sensor seats fully — too wide an air gap starves the signal. Through the mounting hole, rotate the engine by hand and look for chipped or bent reluctor teeth.
- Install a quality sensor and run any required relearn
Fit an OE-grade sensor with the O-ring or spacer supplied, and route its lead away from exhaust heat and the starter. Some vehicles need a crankshaft position variation relearn with a scan tool afterward; skip it and misfire monitoring may not run, with a 'variation not learned' code following.
DIY or shop? With the car in your driveway, the code check, reference and signal measurements, and a sensor swap are within home-mechanic reach when the sensor is accessible at the front of the engine or on the side of the block. Some sit behind the starter, on the bellhousing, or above the transmission and need the car safely on stands. Hand it off when the short is buried inside the harness, when the reluctor looks damaged, or when the vehicle needs a relearn your scanner can't perform — and tow it rather than driving there if it has been stalling.
Tools for the DIY steps: Digital multimeter · Back-probe pins · Scan tool (with relearn function where required) · Socket set and extensions · Jack and jack stands · Wiring diagram
Not sure which step applies to your car? Get the likely cause for your exact vehicle before buying anything for P0337.
Start a case with P0337 and your car. Redline weighs these causes against what your car shows, and names the check that would settle it before you buy parts.
Can I drive with P0337?
Redline can’t determine from a symptom or code alone whether your car is safe to drive.
P0337: common questions
What does 'circuit low' mean on P0337?
The sensor's signal is stuck at or below the minimum the computer expects — essentially flatlined low. That usually means a failed sensor, a wire shorted to ground, or a weak signal from a damaged tone ring, versus P0338 where the same circuit reads too high.
Can P0337 cause my car to stall or not start?
It can — that's the main risk. The crank signal is the computer's timing reference for spark and fuel, so when it drops out the engine dies or cranks without starting. Intermittent versions are common: the car stalls when hot, then restarts after cooling off.
Why does it happen intermittently?
Sensor windings and marginal connections often fail with heat — fine when cold, dropping out as the engine bay warms up. That's why a car with P0337 may stall on the highway, refuse to restart for twenty minutes, then run fine. Don't let a successful restart convince you it's healed.
How much does it cost to fix P0337?
Usually modest — the sensor itself is inexpensive and most replacements take an hour or less, with the total driven by how accessible the sensor is on your engine. A damaged reluctor ring is the exception and is a significantly bigger repair.
Related trouble codes
Don’t have a scanner yet? A ~$25 Bluetooth adapter reads codes like P0337 from your phone. See our guide to the best OBD2 Bluetooth adapters. Run a repair shop? See Redline for shops.
Generic OBD-II reference. Manufacturer-specific behavior varies. Confirm with a scan tool and, for safety-related codes, a professional inspection. Cost ranges are reference ranges, not quotes.
Seeing P0337 on your car?
Every problem becomes a Case. Tell Redline what the car is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.