Is it safe to drive with this code?

Continued driving is not recommended, as the engine may stall unexpectedly or fail to restart, which can be hazardous in traffic. If the vehicle runs, performance will typically be poor, and further stress on other engine components is possible. See our disclaimer for guidance on when to seek professional help.

It may affect your MOT result if the Malfunction Indicator Lamp (engine warning light) is illuminated at the time of the test. Under MOT regulations, a permanently lit MIL is typically a reason for failure. For full details on emissions and warning light rules, please see our MOT disclaimer.

Roughly how much does it cost to fix?

Costs vary by vehicle and location. The sensor itself is often in the low two-figure to low three-figure range, whilst labour can add a further low three-figure amount, particularly if access is awkward. Total repair costs commonly fall within the low to mid three-figure bracket. Main dealers may charge more than independent garages. If wiring repairs or ECM work are needed, costs can rise towards the high three-figure band.

Can I just reset the code and see if it comes back?

Clearing the code with a scanner may temporarily extinguish the warning light, but the underlying fault will typically cause the code to return unless the root cause—whether a faulty sensor, poor connection, or wiring issue—is properly addressed.

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← All fault codes | Misfire

P0321

Powertrain

Ignition/Distributor Engine Speed Input Circuit Range/Performance

The engine control unit has detected that the signal from the crankshaft position sensor (or distributor speed sensor on older vehicles) is erratic, falls outside the expected range, or isn't performing consistently.

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ⓘ Information only. This page provides general educational information about fault code P0321. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.

Recommended next steps

Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.

What does P0321 mean?

P0321 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Ignition/Distributor Engine Speed Input Circuit Range/Performance.

This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.

About Misfire codes

Misfire codes flag cylinders that aren't firing properly. P0300 means random cylinder; P0301-P0312 each name a specific cylinder. Causes range from worn spark plugs to failed coils, leaking injectors, or compression issues. A flashing warning light during a misfire risks catalytic converter damage.

P0321 is one of 73 codes in this category. Browse all Misfire codes →

What we know about P0321 specifically

We record the SAE J2012 standardised definition and the system this code belongs to, but we have not yet published detailed driver-reported symptoms, common causes, or step-by-step diagnostic guidance for P0321.

Rather than invent that information by generating generic content from a template, we leave it out. For specific guidance, the most reliable sources are:

•your vehicle's own service manual or manufacturer-specific technical bulletins
•a qualified mechanic with a manufacturer-level diagnostic tool
•a marque specialist familiar with your make and model

Codes nearby

Codes adjacent to P0321 in the P-code series. Many fault codes appear together with their neighbours because they relate to the same circuit or component.

P0318 Rough Road Sensor A Signal Circuit

P0319 Rough Road Sensor B Signal Circuit

P0320 Ignition/Distributor Engine Speed Input Circuit

P0322 Ignition/Distributor Engine Speed Input Circuit Low

P0323 Ignition/Distributor Engine Speed Input Circuit High

P0325 Knock Sensor 1 Circuit Malfunction (Bank 1)

Other Misfire codes

Other fault codes in the same system as P0321. The ones with detailed guides have plain-English explanations, symptoms, causes, and diagnostic steps.

P0300

Random/Multiple Cylinder Misfire Detected Detailed guide

P0301

Cylinder 1 Misfire Detected Detailed guide

P0302

Cylinder 2 Misfire Detected Detailed guide

P0303

Cylinder 3 Misfire Detected Detailed guide

P0304

Cylinder 4 Misfire Detected Detailed guide

P0305

Cylinder 5 Misfire Detected Detailed guide

Spotted an issue or have something to add? Mechanics, technicians, and drivers who have first-hand experience with P0321 can submit a correction or expansion. We review every submission before publishing, mechanic submissions are prioritised.

Information only, not professional advice

The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →

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