P0322
Ignition/Distributor Engine Speed Input Circuit No Signal
If your vehicle's onboard computer has flagged the diagnostic trouble code P0322, it refers to a detected anomaly regarding "Ignition/Distributor Engine Speed Input Circuit No Signal". This systemic engine fault needs a targeted check before symptoms expand.
Driver's Summary
P0322 is triggered when the PCM detects an abnormal condition associated with ignition/distributor engine speed input circuit no signal. In practice, this fault causes engine cranks but will not start, no tachometer reading. Given the high severity of this code, continuing to drive risks significant mechanical damage. Have it diagnosed immediately.
Symptoms
Engine cranks but will not start, no tachometer reading
Common Causes
- Dead crankshaft position sensor
- Unplugged speed sensor
- Severed wiring harness
- PCM failure
How to Fix
- 1 Replace crankshaft position sensor
- 2 Ensure sensor is plugged in securely
- 3 Repair cut wiring
- 4 Test PCM for signal reception
Technical Explanation
The ECM detects code P0322 by continuously monitoring the relevant sensor circuit against calibrated threshold values stored in its non-volatile memory. The PCM monitors crankshaft rotational velocity via the CKP sensor at a resolution of individual tooth gaps on the reluctor ring. A combustion event in each cylinder produces a measurable acceleration spike; its absence or weakness is flagged as a misfire event within a 200-revolution or 1000-revolution test window. The fault remains stored in memory even after the MIL is cleared; it becomes a confirmed DTC after failing two consecutive drive cycles, and the PCM logs a freeze frame record of the engine's exact operating state at the moment of detection.
Is It Safe to Drive?
Driving with an active P0322 fault risks accelerating damage to dead crankshaft position sensor and related components. The longer the fault persists, the more expensive the eventual repair becomes — what starts as a sensor or solenoid issue can escalate to major mechanical failure.
Mechanic's Pro Tip
Before replacing any component on P0322, spend 5 minutes inspecting the wiring harness and connector first — corrosion, chafed insulation, and backed-out pins cause the majority of these faults and cost nothing to fix. Use a multimeter to measure voltage drop across the connector pins under load; anything above 0.1V indicates excessive resistance that will cause intermittent failures even after replacing the sensor.
Crank sensor replacement: $150 - $350