Ignition & misfire · Powertrain · generic (SAE-defined)
P0320: Ignition/Distributor Engine Speed Input Circuit
P0320 means the engine computer lost or received an erratic engine speed signal from the ignition or distributor reference circuit, which it needs to time spark and fuel.
Standard title per SAE J2012 / ISO 15031-6 · Updated 2026-11-07 · By CarWhere Research
How P0320 sets
The powertrain control module (PCM) relies on an engine speed reference signal, which on older engines comes from a distributor pickup or ignition module and on newer ones from a crankshaft position sensor. P0320 sets when that signal is missing, intermittent, or noisy while the engine is cranking or running. What counts as the engine speed input depends on the manufacturer.
Common causes of P0320
Roughly most likely first; the actual cause depends on the vehicle and needs testing to confirm.
- Failed distributor pickup coil or ignition module
- Faulty crankshaft position sensor on engines that use it for this input
- Damaged, loose, or corroded wiring and connectors
- Electrical interference from damaged plug wires or aftermarket accessories
- Damaged reluctor ring or trigger wheel
- Rarely, a PCM fault
P0320 symptoms
- Check engine light on
- Intermittent stalling or cutting out
- Crank but no start
- Tachometer dropping or behaving erratically
- Misfire or hesitation
How P0320 is diagnosed
- Check freeze frame data and look for crankshaft or camshaft position sensor codes.
- Identify the engine speed input source for the vehicle in service information.
- Inspect wiring and connectors at the distributor or sensor for damage and corrosion.
- Watch the rpm signal on a scan tool while cranking and while wiggling the harness.
- Test the sensor or pickup output with an oscilloscope or multimeter per specification.
- Check the reluctor or trigger wheel for damage.
Typical fixes for P0320
- Repair wiring or connector faults
- Replace the distributor pickup or ignition module
- Replace the crankshaft position sensor
- Replace damaged spark plug wires causing interference
Replace parts only after testing confirms the cause — a code names the circuit or condition that failed a check, not necessarily the faulty part. We don’t publish per-repair prices; for what households actually spend on upkeep, see car repair costs.
Manufacturer notes
Some manufacturers use P0320 for the crankshaft position signal or ignition module reference rather than a distributor. Definitions can vary by manufacturer; check factory service information.
Related codes & warning lights
P0320 FAQ
What does code P0320 mean?
P0320 means the engine computer lost or received an erratic engine speed signal from the ignition or distributor reference circuit, which it needs to time spark and fuel. The standard definition is "Ignition/Distributor Engine Speed Input Circuit."
Can I drive with a P0320 code?
Not reliably. The engine may stall, cut out, or fail to restart without warning, so limit driving and avoid traffic until the cause is found.
Why does the tachometer drop to zero with P0320?
The tachometer often uses the same engine speed signal. If that signal drops out, the gauge can fall to zero and the engine may stall at the same moment.
Is P0320 common on newer cars?
It is more often seen on older distributor-equipped engines. Newer engines usually report crankshaft signal problems with P0335 to P0339 instead.
Keep researching
Engine guides by brand (known issues, specs)
More ignition & misfire codes
Sources
- SAE J2012 — Diagnostic Trouble Code Definitions (standard code titles)
- ISO 15031-6 — Road vehicles: communication between vehicle and external equipment for emissions-related diagnostics, Part 6: Diagnostic trouble code definitions
- U.S. EPA — Vehicle Emissions Inspection and Maintenance (I/M) programs
- U.S. EPA, 40 CFR 86.1806-17 — Federal onboard diagnostics requirements for light-duty vehicles
General information written by CarWhere Research, not a diagnosis of your vehicle. Manufacturers can add their own sub-definitions and test conditions; confirm with the factory service information for your year, make and model. Before paying for a repair, check NHTSA for open recalls and your warranty booklet: federal law requires an emissions warranty on major emission-control parts such as the catalytic converter and engine computer.