This code indicates that the engine computer has detected an abnormally high voltage in the ignition switch accessory (ACC) position circuit. It typically points to a short to power, damaged wiring, or a failing ignition switch rather than a computer malfunction.
Internal shorts or worn contacts within the ignition switch can send continuous or excessive voltage down the accessory circuit.
Chafed or damaged wiring in the accessory circuit can short to an adjacent power source, causing a high voltage reading at the computer.
Corroded, loose, or damaged connectors at the ignition switch or inline harness can alter circuit resistance and trigger a false high voltage condition.
The engine computer is highly unlikely to cause this code, though an internal failure in the reference voltage circuit is theoretically possible.
No, it almost never does. While some mechanics might hastily blame the computer, the cause is almost always a faulty ignition switch or a wiring issue. Replacing the PCM for this code is usually an incorrect and expensive misdiagnosis.
It means the computer is detecting voltage on the accessory circuit where it shouldn't be, or a higher voltage than expected, typically caused by a short to power or a stuck switch.
While the car might run, the underlying electrical issue could drain your battery or cause erratic accessory behavior, so it should be diagnosed and repaired promptly.
Not always. The key cylinder is the mechanical part you put the key into, while the ignition switch is the electrical component attached to it that actually routes the power.