P0791 — Intermediate Shaft Speed Sensor A Circuit

P0791: Intermediate Shaft Speed Sensor A Circuit — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

Intermediate Shaft Speed Sensor A Circuit. Basic catalogue definition; diagnostic details have not yet been reviewed.

Affected system: Powertrain

Symptoms

  • A transmission warning may accompany a fault in the intermediate-shaft speed sensing circuit.
  • Gear changes can be delayed or abrupt; the vehicle may select a restricted operating mode.

Possible causes

  • A damaged speed sensor, a loose connector or compromised wiring can disturb the speed signal.
  • A transmission-control fault remains a possibility only after sensor and circuit checks.

What to check

  • Record this code and related transmission faults; compare the intermediate-shaft speed reading with other available speed data.
  • Inspect the sensor connector and harness; perform supply, ground and signal tests specified for this gearbox before replacing parts.

Also written as: P0791-00, P079100, PO791 (some scan tools add the fault-type byte, e.g. -00).