OBD-II Code
P0321
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)
$80–$1,800
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
P0321 indicates the ignition or distributor engine speed input is out of expected range or performance — meaning the signal is present but the frequency, amplitude, or pattern doesn't match what the ECM expects.
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 procedureP0321 indicates the ignition or distributor engine speed input is out of expected range or performance — meaning the signal is present but the freque…
P0321 indicates the ignition or distributor engine speed input is out of expected range or performance — meaning the signal is present but the frequency, amplitude, or pattern doesn't match what the ECM expects. This is more diagnostic-sensitive than P0320 (no signal) or P0322 because intermittent signal degradation can come from many sources: a partially failed sensor putting out a weak signal, a damaged reluctor tooth on the crank tone wheel, a worn timing chain stretching the crank-to-cam relationship past the learned correlation window, or harness shielding failure letting alternator/coil noise corrupt the signal. Start with a scope on the CKP signal at cranking and idle — a healthy magnetic pickup sweeps from about 0.5V peak-to-peak at cranking up to 80V+ at redline; a Hall-effect 3-wire should produce a clean 0-5V square wave with consistent duty cycle.
Caveat
aftermarket lightweight underdrive pulleys without proper reluctor alignment will throw P0321 from day one; verify pulley OEM-spec before chasing sensor parts.
Vehicle-specific patternsBMW M54/M52TU inline-6 (E46 330i, E39 530i, E60 525/530i, 1999-2006) — stretched timing chain plus worn guides cause CKP-to-CMP correlation drift, P0…
BMW M54/M52TU inline-6 (E46 330i, E39 530i, E60 525/530i, 1999-2006) — stretched timing chain plus worn guides cause CKP-to-CMP correlation drift, P0321 with hot-start hesitation; replace chain, guides, and tensioner as a kit ($400-700 parts, 8-12 hr labor). Toyota 2GR-FE V6 (Camry, Avalon, RAV4, 2007-2017) — VVT-i actuator wear creates intermittent P0321 paired with cold-start rattle. GM 3.6L LY7/LLT V6 (CTS, Acadia, Traverse, 2007-2011) — timing chain stretch is the signature on this engine family by 100K miles. Nissan VQ35DE V6 (Maxima, Altima, Murano, 350Z, 2002-2008) — failed CKP sensor producing weak signal at hot operating temp; sensor is $60-90 part on the bellhousing.
Estimated repair$80 to $1,800.
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