OBD-II trouble code
P0320: Ignition/Distributor Engine Speed Input Circuit
The engine management system has lost confidence in the signal that tells it how fast the crankshaft is turning. The word 'Distributor' in the name is a leftover from the 1990s, and working out whether your engine actually has one is the first thing that decides the repair.
Quick facts
- System
- Powertrain
- Category
- Sensors / Timing
- Severity
- High severity
- Drivable
- No — stop driving until repaired
- Repair cost range
- $120 – $900
- DIY difficulty
- Intermediate DIY
What does P0320 mean?
Every decision an engine control module makes about spark and fuel starts from one number: where the crankshaft is right now and how fast it is turning. Without it the module cannot work out when to fire a plug, when to open an injector, or even whether the engine is running. This code is set when that engine speed signal goes missing, becomes unreliable, or reports something the module knows cannot be true.
The name of the code is the most misleading thing about it, and it is worth unpicking before you touch anything. When this number was assigned, a great many engines still took their speed reference from a pickup inside the distributor — a magnetic pickup coil or a Hall-effect switch sitting under the cap, triggered by a reluctor spinning on the distributor shaft. That is where 'Ignition/Distributor' comes from. On the overwhelming majority of vehicles built since distributors were phased out, there is no distributor anywhere on the engine, and the same signal comes from a crankshaft position sensor bolted to the block, the bellhousing or the front cover, reading a toothed reluctor wheel on the crank or the flywheel.
That matters because the two architectures have almost nothing in common as repairs. A distributor pickup lives inside a component that also carries the rotor, cap and shaft bushings, is often not sold separately, and on a worn distributor the shaft can develop enough side play to change the air gap and corrupt the signal all by itself — a mechanical fault dressed up as an electrical one. A crank sensor is a standalone part, usually inexpensive, but sometimes buried behind the harmonic balancer, the starter or the transmission bellhousing where the labour dwarfs the part. Establish which one you have before you price anything.
The other thing to understand is why this code behaves so differently from most circuit faults. A failed coolant temperature sensor gives the module a bad number and it carries on with a substitute. There is no substitute for engine speed. When this signal disappears, the engine stops — not gradually, not with a warning light and a limp mode, but immediately, exactly as though the ignition key had been switched off. It is also entirely capable of doing that once and then behaving perfectly for a fortnight. Treat a stored P0320 on a car that currently runs fine as a warning about a stall that has not happened yet, not as evidence the fault has gone away.
One further caution: several manufacturers use this number for something narrower than the generic definition suggests, sometimes pointing at an ignition control module output rather than the sensor input. If the vehicle's own service information disagrees with the generic wording, follow the vehicle.
Common causes
- Failed crankshaft position sensor on an engine with no distributor, which is the majority case on anything modern
- Worn or failed pickup coil inside the distributor on older engines that still have one
- Excessive distributor shaft side play changing the pickup air gap as the shaft wobbles
- Open, shorted or chafed wiring between the sensor and the control module
- Corroded or partly unseated connector at the sensor, which sits in one of the dirtiest, wettest places on the engine
- Damaged, cracked or contaminated reluctor wheel giving the module a pattern it rejects
- Failed ignition control module on systems where it conditions the signal before passing it on
- Poor engine-to-body ground raising the reference the signal is measured against
Symptoms
- Engine cranks but will not start
- Engine cuts out instantly while driving, as though the key had been turned off
- Tachometer needle drops to zero or does not move during cranking
- Long cranking before the engine catches
- Check engine light on, sometimes with the car running normally between episodes
- Random misfires or hesitation as the module works from a degraded reference
Diagnostic steps
- 1.Open the bonnet and establish whether the engine has a distributor at all. Everything after this step branches on the answer, and guessing wastes the most time of any mistake in this diagnosis.
- 2.Watch the tachometer while a helper cranks the engine. A needle that stays at zero means the module is seeing no engine speed at all and moves the fault to the sensor, its wiring or its supply.
- 3.Read all stored codes before clearing anything. A camshaft sensor code alongside this one usually points at a shared supply, a shared ground or a timing problem rather than at two independent failures.
- 4.Inspect the connector at the sensor or distributor for corrosion, spread pins, oil intrusion and a latch that has not clicked home. This connector lives in heat, road spray and oil mist and fails far more often than the part it feeds.
- 5.On a distributor engine, grasp the rotor shaft and check for side play before condemning the pickup. A shaft that moves visibly will change the air gap every revolution and produce this fault with a perfectly good pickup fitted.
- 6.Back-probe the signal wire and watch the waveform on a scope while cranking. A signal that is present but ragged, clipped or noisy is a different problem from one that is absent, and only a scope tells them apart.
- 7.Check the sensor's supply and ground at the connector rather than at the module, so the wiring between them is inside the test rather than outside it.
- 8.Remove the sensor and inspect its tip and the reluctor teeth for metal debris, chipped teeth and impact damage before fitting a replacement.
Repair cost
$120 – $900
A crankshaft position sensor is commonly $25 to $150 and often takes under an hour, so many repairs land between $120 and $350. The cost escalates when the sensor sits behind the harmonic balancer, the starter or the bellhousing, where two to four hours of labour is normal and the bill can reach $700 or more. A distributor pickup that is not sold separately forces a complete distributor, typically $90 to $450 in parts on top of fitting and timing. Wiring and connector repairs are usually the cheapest outcome and are worth ruling in before any part is ordered.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with crankshaft position sensor replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.