P0322

Universal

Ignition/Distributor Engine Speed Input Circuit No Signal

Definition source: General OBD-II reference catalog
Definition verification: Not independently verified for display.
Time: Varies by diagnosis and vehicle | Diagnostic difficulty: Medium
High Severity

The engine control system is not detecting an expected engine-speed signal from the ignition or distributor input circuit. That signal helps the system manage engine operation, so its absence may cause hard starting, stalling, or a no-start condition. The code identifies a detected signal problem; it does not by itself prove that a particular sensor or part has failed. The exact system and diagnostic procedure depend on the vehicle's model, year, and engine.

Report an error with this code

⚠️ Before You Begin (Safety First)

If the engine stalls, will not restart reliably, or loses power in traffic, pull over somewhere safe and arrange assistance rather than continuing to drive. Avoid working near moving engine parts, and do not probe electrical circuits unless you know how to do so safely.

Common Symptoms

  • The engine may crank but fail to start if the control system is not receiving the speed signal it needs.
  • The engine may stall or run erratically if the signal is intermittent or disappears during operation.
  • Starting may be difficult or inconsistent.
  • The tachometer may not show engine speed on some vehicles if it relies on the affected signal.
  • There may be no noticeable symptoms if the condition is intermittent or does not affect normal operation at the time.

Common Causes

  • An engine-speed pickup or ignition/distributor signal generator may fail to produce a signal, where that component is used.
  • A damaged, loose, corroded, or disconnected wire or connector may interrupt the signal.
  • A fault in circuit power or ground may prevent the signal source from operating correctly.
  • An ignition component or module in the signal path may not transmit the engine-speed input.
  • A mechanical problem affecting a distributor or its drive may prevent a signal from being generated on vehicles that use that arrangement.
  • A control-module or related circuit fault is possible, but should be considered only after the signal source and wiring are tested.

Diagnostic Steps

  1. Note whether the engine cranks, starts, stalls, or shows other warning lights, and record any related codes to help guide diagnosis.
  2. With the engine off, visually inspect accessible wiring and connectors related to the ignition or engine-speed input for looseness, corrosion, or obvious damage.
  3. Check the vehicle-specific owner information for any relevant fuses, and replace a fuse only with the specified type and rating if it is visibly blown.
  4. If you have a suitable scan tool, check whether engine speed is displayed while cranking; an absent reading can help direct further circuit testing but does not identify the failed part by itself.
  5. Use vehicle-specific service information for any electrical tests. If testing requires specialized signal equipment or the circuit is not clearly identified, have a qualified technician continue diagnosis.

When to Call a Professional

Check for related diagnostic codes and review scan data for engine speed while cranking, where supported. Inspect the relevant wiring and connectors, then test circuit power, ground, continuity, and signal using the vehicle-specific service information. A suitable oscilloscope or other signal-testing equipment may be needed to distinguish a missing input signal from a wiring, ignition, or control-system problem.

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Commonly Asked Questions

Does P0322 prove that the engine-speed sensor needs replacement?

No. The code indicates that the expected signal is not being detected. The cause could be the signal source, wiring, connectors, power or ground, an ignition component, or another part of the circuit.

Can I keep driving with this code?

Driving may be unsafe if the engine stalls, loses power, or is difficult to restart. If those symptoms occur, stop in a safe place and arrange assistance. A technician should assess the vehicle before continued use.

What does the engine-speed input signal do?

It provides information about engine rotation to the vehicle's control system, which uses engine-speed information to manage engine operation. The exact circuit design varies by vehicle.

How can a technician tell whether the signal source or wiring is at fault?

The technician can compare scan data with circuit tests, check power and ground where applicable, and examine the signal using suitable test equipment. Vehicle-specific service information is needed to interpret results.

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