OBD-II Code
P0373
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$180–$850
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
P0373 means the PCM is seeing the high-resolution timing reference signal (often the CKP-B or secondary crankshaft sensor on engines that run a redundant pair) but the pulses are arriving intermittently or with erratic spacing — missing edges, doubled edges, or jitter outside the ECM's tolerance window.
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 follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
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
- Check engine light
Read the full diagnostic procedureP0373 means the PCM is seeing the high-resolution timing reference signal (often the CKP-B or secondary crankshaft sensor on engines that run a redun…
P0373 means the PCM is seeing the high-resolution timing reference signal (often the CKP-B or secondary crankshaft sensor on engines that run a redundant pair) but the pulses are arriving intermittently or with erratic spacing — missing edges, doubled edges, or jitter outside the ECM's tolerance window.
Cheapest-first ladder on the shop floor
- wiggle-test the CKP-B harness with the engine idling while watching scan-tool RPM-B / cam-correlation live data — if RPM stutters or drops momentarily, you've already found the bad connector or chafed wire.
- Scope the signal at the sensor connector — a Hall-effect CKP-B should produce a clean 0-5V square wave with crisp rising edges at cranking (300+ pulses/sec at 200 rpm cranking on a 58-tooth wheel), and a VR (variable reluctance) sensor should produce a 0.5-1.5V AC sine that grows to 5-15V peak-to-peak at 2,500 rpm. Ragged baselines, missing teeth that aren't the synchronization gap, or amplitude under 0.4V at cranking on a VR sensor all confirm sensor or air-gap problems.
- Pull the sensor and inspect the tip for ferrous debris — VR sensors are magnets and they collect timing-cover swarf that bridges the air gap and corrupts the waveform; wipe with a clean rag and retest before condemning the part.
- Inspect the reluctor/tone ring on the crankshaft for chipped teeth or a bent flange — a single bent tooth shows up on the scope as one bad edge per crank revolution and reads as 'intermittent erratic.' Expensive-misdiagnosis caveat: before you order a $300 CKP-B sensor, check the alignment of the reluctor wheel — on engines that share a timing-cover-mounted sensor (Ford 6.0L Powerstroke, GM Duramax LB7), a stretched timing chain or a worn cover bushing lets the reluctor wobble axially, producing intermittent pulses that look exactly like a bad sensor; replacing the sensor without correcting the chain/cover lasts about a week before P0373 returns.
Vehicle-specific patterns2003-2010 Ford 6.0L Powerstroke (F-250/350, Excursion) commonly throws P0373 alongside P0341/P0344 because the CMP and CKP-B share heat-soak failure…
- 2003-2010Ford 6.0L Powerstroke (F-250/350, Excursion) commonly throws P0373 alongside P0341/P0344 because the CMP and CKP-B share heat-soak failure modes on the front timing cover — the connector pins corrode from oil-vapor blow-by and the signal drops at hot idle; reseating with dielectric grease buys time but the proper fix is a sensor + pigtail.
- 2001-2010GM Duramax LB7/LLY/LBZ throws P0373 when the camshaft position correlation drifts — same redundant-timing-reference architecture, and the CKP-B sits on the engine block exposed to road spray; the harness chafes against the bracket and the signal goes intermittent during cold-soak starts.
- 2007-2009Mercedes M642 BlueTec 3.0 V6 diesel (Sprinter, GL320, ML320, R320 BlueTec) frequently throws P0373 from a known CKP wiring harness rub-through near the bell-housing — the wire insulation cooks against the exhaust manifold and shorts intermittently.
- 2009-2014BMW N57 3.0 inline-6 diesel throws P0373 typically from a failing crank sensor itself (Bosch units that go non-linear at temperature).
Estimated repair$180 to $850.
Look up another code
More free tools