OBD-II Code · Powertrain
P0338
Crankshaft Position Sensor A Circuit High
Severity
critical
Highest on our scale. Expect major repair cost if it is ignored.
Can you drive it
Not for long
Driving on this one risks further damage. Get it to a shop rather than carrying on with it.
Indicative cost (USD)
$120–$650
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
CKP signal voltage pegged above threshold.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- No-start
- Stall
- Check engine light
Likely causes
- Short to power on signal wireMost common
- Sensor internal open
- Connector pin backed out
Read the full diagnostic procedureP0338 means the CKP signal voltage is pegged above the high-threshold limit — typically stuck at 5V reference voltage or higher with no pulsing to gr…
P0338 means the CKP signal voltage is pegged above the high-threshold limit — typically stuck at 5V reference voltage or higher with no pulsing to ground, which the ECM reads as a shorted-to-power or open-circuit condition. The signal looks like a flat line at the top of the scope rather than a pulse train.
Cheapest-first ladder
- key on engine off, back-probe the signal wire at the ECM connector and measure to ground (should read 5V or 12V depending on sensor type with no pulsing — that confirms the high stuck condition).
- Unplug the sensor and check if the signal wire drops to 0V (if it stays high, you have a short to power upstream of the sensor; if it drops, the sensor itself is shorted internally).
- Inspect the harness routing for chafing against valve cover bolts or intake brackets where the signal wire could be shorted to a 12V feed.
- Check for water intrusion in the CKP connector — corrosion can create high-resistance paths that pull the signal high.
- The expensive misdiagnosis is condemning the ECM for an internal pull-up fault when the actual problem is a chafed wire touching a fuel injector harness.
Vehicle-specific patternsFord 5.4 3V Triton (2004-2010 F-150, Expedition, Navigator) sets P0338 when the cam phaser failure corrupts CMP timing so badly that the ECM throws c…
Ford 5.4 3V Triton (2004-2010 F-150, Expedition, Navigator) sets P0338 when the cam phaser failure corrupts CMP timing so badly that the ECM throws crank-side codes as collateral — diagnose the phaser rattle first, fix the CMP/phaser side, and the crank-side code clears. GM 3.6L LY7 throws P0338 when the CKP connector pin backs out from heat cycling and the wire lifts off the sensor pin, presenting as a stuck-high open. Subaru EJ25 (2005-2012 Outback, Forester, Impreza) sees P0338 when oil leaks from the cam carrier soak the CKP connector and corrode the pin terminals to high resistance.
- 2011-2016Chrysler 3.6 Pentastar sets P0338 intermittently from a poorly-crimped ECM-side pin at the main connector — wiggling the connector loom often reproduces it.
Estimated repair$120 to $650.
Look up another code
P0338 — frequently asked
What does a P0338 code mean?
CKP signal voltage pegged above threshold.
What causes a P0338 code?
Common causes: Short to power on signal wire; Sensor internal open; Connector pin backed out.
What are the symptoms of a P0338 code?
Typical symptoms: No-start; Stall; Check engine light.
Is it safe to drive with a P0338 code?
Not for long. Driving on this one risks further damage. Get it to a shop rather than carrying on with it. Estimated repair: $120-$650.
How do I diagnose a P0338 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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