OBD-II trouble code
P0322: Ignition/Distributor Engine Speed Input Circuit No Signal
Nothing at all is reaching the module — not a weak signal, not a noisy one, none. Total absence is the easiest fault in this family to pin down, and which of two sensor types you have decides the entire test sequence.
Quick facts
- System
- Powertrain
- Category
- Sensors / Timing
- Severity
- High severity
- Drivable
- No — stop driving until repaired
- Repair cost range
- $100 – $1,200
- DIY difficulty
- Intermediate DIY
What does P0322 mean?
This is the code that arrives with a car on a flatbed. Total absence of the engine speed signal usually means an engine that cranks over healthily and never fires, because the module has no idea the crankshaft is moving and therefore commands no spark and no injection.
The useful thing about a complete absence is that there is nothing intermittent to chase. Faults that come and go are the hard ones; a fault that is present every second of every test is the easy one, and it will still be there when you connect a meter. Everything is measurable on the spot, and a careful technician can usually name the cause in under half an hour.
What decides that half hour is a distinction that matters more here than anywhere else in this family: whether the sensor generates its own signal or is fed one. A variable reluctance sensor is a coil of wire around a magnet, with two wires and no supply. Spin a toothed wheel past it and it produces its own alternating voltage — no power feed, nothing to check upstream, and a straightforward coil resistance measurement that will read a sensible few hundred to a couple of thousand ohms if the winding is intact and open circuit if it is not. A Hall-effect sensor is an active device with three wires: a supply from the module, a ground, and a signal it switches. It cannot produce anything if its supply is missing, so on a three-wire sensor the very first measurement is whether the reference voltage is arriving at all. Testing a Hall sensor as though it were a coil produces a meaningless reading and sends people to the parts counter for no reason.
Count the wires at the connector before you do anything else. It takes ten seconds and it decides which of two completely different test sequences applies.
The other line of enquiry particular to a no-signal fault is recent work. This sensor commonly lives on the bellhousing, at the rear of the block or behind the starter — which is to say, in exactly the region that gets disturbed when a transmission, clutch, starter or flywheel is removed. A sensor left dangling, a bolt not refitted, a connector unclipped and forgotten, a harness pinched between the engine and the gearbox as they were drawn together: all of these produce a car that ran perfectly before the job and will not start after it. If the vehicle has been apart recently, look there before looking anywhere else.
Finally, do not overlook the wheel. A reluctor that has sheared off its mounting, a flywheel ring that has spun on the crank, or a sensor whose tip has been ground away by contact will all deliver an honest zero.
Common causes
- Open circuit inside the sensor winding, which reads infinite resistance on a two-wire type
- Missing supply voltage or ground to a three-wire Hall-effect sensor, which cannot output anything without them
- Sensor left unbolted, unplugged or dangling after transmission, clutch, starter or flywheel work
- Harness pinched or severed between the engine and gearbox during reassembly
- Broken wire inside the insulation where the harness flexes with engine movement
- Connector pushed apart by vibration or corroded to the point of no contact
- Sheared, missing or spun reluctor wheel giving the sensor nothing to read
- Failed input circuit inside the control module, which is rare and should be the last conclusion rather than the first
Symptoms
- Engine cranks strongly but never fires
- Tachometer stays at zero throughout cranking
- No spark and no injector pulse when tested
- Engine stopped while driving and will not restart
- Check engine light on, or on some vehicles no light at all because the module never sees the engine run
- Fuel pump primes normally, which confirms the problem is not fuel supply
Diagnostic steps
- 1.Count the wires at the sensor connector. Two wires means a self-generating reluctance sensor; three means an active Hall-effect device with a supply to verify. Every test after this depends on the answer.
- 2.Ask whether anything has been removed or refitted near the bellhousing, starter or front cover recently. On a no-signal fault the answer is frequently the whole diagnosis.
- 3.Confirm the sensor is physically present, fully seated and bolted down, with its connector latched. This sounds trivial and is the single most common finding after recent work.
- 4.On a two-wire sensor, measure winding resistance across the pins with the connector unplugged. Open circuit condemns it outright; a plausible reading means the fault is elsewhere.
- 5.On a three-wire sensor, check for the reference voltage and a good ground at the connector with the ignition on, before assuming the sensor itself has failed.
- 6.Verify signal continuity from the sensor connector all the way to the module pin rather than testing the two ends separately, so a break inside the insulation cannot hide.
- 7.Crank the engine while watching for any output on a scope at the module end. A genuine zero at the module with a healthy sensor and good wiring is the only evidence that justifies suspecting the module.
- 8.Remove the sensor and look through the hole at the reluctor while an assistant cranks. A wheel that is not turning, is missing, or has sheared explains the absence completely.
Repair cost
$100 – $1,200
This is often the cheapest code in the family to put right because the cause is frequently a disconnected plug, a loose sensor or a pinched wire found in minutes. A straightforward sensor replacement usually runs $120 to $400. A broken harness section is $100 to $350 depending on access. The expensive outcomes are mechanical: a sheared or spun reluctor wheel can require the transmission or the front cover off, pushing the job past $1,000, and a genuinely failed control module means replacement plus programming.
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.