P0338 code: Crankshaft Position Sensor A Circuit High
P0338 means crankshaft Position Sensor A Circuit High. The code says where to look, not what failed — the fix depends on which cause your car actually has.
What P0338 means
The crankshaft position sensor is the computer's master timing reference for firing spark and fuel. P0338 means the crank sensor's signal is reading HIGH — pegged at or above its maximum expected level — the mirror image of P0337 (circuit low). In practice this usually traces to a failed sensor, a wiring problem such as an open circuit or a short to voltage, or a corroded connector; a break anywhere in the circuit can leave the computer seeing a fixed high reading instead of the alternating signal a spinning crank should produce. The consequences are the same as any lost crank signal: stalling, hard starting, or a crank-but-no-start, often intermittent and heat-sensitive. Because the engine can quit without warning, this code deserves prompt attention.
P0338 symptoms
- Engine cranks but won't start, or starts hard
- Sudden stalling, sometimes with no warning
- Intermittent cutting out, often when hot
- Tachometer reading erratically or dropping to zero
- Check-engine light
What it costs to fix P0338
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 cheap and the job is usually short — the variable is access, since some crank sensors are behind the starter or bellhousing rather than up front. Chasing an intermittent wiring fault can add diagnostic time.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0338 for my exact vehicle →
How to fix P0338
Moderate — doable at home with common tools and patience
- Note when it stalls and what the tach does
P0338 can kill the engine without warning, so record the conditions: hot or cold, and whether the tachometer dropped to zero just before the stall, which on many cars is a classic sign of a lost crank signal. If it won't restart until it cools, a heat-sensitive sensor is likely; either way, tow it rather than risking another stall in traffic.
- Check terminal grip and the sensor ground path
An open ground or a loose terminal lets the signal float high. With the battery disconnected, measure resistance from the sensor's ground pin to the computer's sensor-ground pin — it should be close to zero ohms. Then push a matching test probe into each female terminal; one that slides in with no drag needs repinning.
- Look for the signal wire touching a powered circuit
With the sensor unplugged and the key on, the signal pin should show only the computer's own pull-up, often around 5 volts on Hall-type sensors. Battery voltage there means a short to a 12-volt wire — check where the harness passes the alternator, starter cable, or injector feeds, and look for melted spots where two wires have fused.
- Heat-test the sensor before you buy one
With a scan tool showing RPM, or a scope on the signal, warm the sensor body gently with a heat gun while the engine idles, keeping heat away from fuel lines and plastic parts. An RPM dropout or stumble as it heats confirms an internal break that opens when hot; no change sends you back to the wiring and connector.
- Fit a quality sensor and verify through a full heat cycle
Install an OE-grade sensor with its new seal, perform any crank relearn the service info calls for, and confirm the fix with a long drive followed by a hot restart. If P0338 returns on a new sensor and verified wiring, a cracked reluctor or a computer input fault is next — that's scope work for a shop.
DIY or shop? Most of this is multimeter work and patience: the ground and short-to-voltage checks and the heat test need nothing beyond a scan tool and a heat gun. The sensor swap is DIY when it's mounted at the timing cover or an open part of the block; when it's tucked behind the starter or against the transmission, getting at it is the real job. Go to a shop if the fault stays intermittent and you can't catch it, if a relearn needs dealer-level software, or if the engine keeps stalling — have it towed, not driven.
Tools for the DIY steps: Digital multimeter · Scan tool with live RPM data · Heat gun · Terminal test probe kit · Socket set · Wiring diagram
Not sure which step applies to your car? Get the likely cause for your exact vehicle before buying anything for P0338.
Start a case with P0338 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 P0338?
Redline can’t determine from a symptom or code alone whether your car is safe to drive.
P0338: common questions
What's the difference between P0338 and P0337?
Both are crank sensor circuit faults; the difference is direction. P0337 means the signal is stuck low (often a short to ground or dead sensor), while P0338 means it's stuck high (often an open circuit, short to voltage, or failed sensor). Either way the computer loses its timing reference.
Can I drive with P0338?
Not something a code can answer by itself. A failing crank signal can drop out without warning and stall the engine — potentially in traffic. Get it diagnosed quickly, avoid depending on the car until it's fixed, and if it stalls, have it towed.
Why does my car stall when hot and restart when it cools?
That's the classic failing-crank-sensor pattern: heat opens a marginal winding or connection, killing the signal, and it returns once things cool down. If P0338 comes with hot-stall behavior, the sensor is the prime suspect even if it tests fine cold.
How much does it cost to fix P0338?
Typically a modest repair — the sensor is an inexpensive part and usually takes an hour or less to swap, with total cost driven by how buried the sensor is on your engine. Wiring repairs are similar once the fault is located.
Related trouble codes
Don’t have a scanner yet? A ~$25 Bluetooth adapter reads codes like P0338 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 P0338 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.