This code indicates that the engine computer has detected an abnormally low voltage in the ion current sensing circuit for cylinder 1. The ion sensing system monitors the electrical conductivity across the spark plug gap during combustion to detect misfires or engine knock. A low reading typically means the system cannot properly read the ionization in that specific cylinder.
The ignition coil for cylinder 1 may have failed internally, preventing proper ionization or signal generation to the engine computer.
A spark plug with excessive wear, carbon fouling, or an incorrect gap can prevent the ion current from forming properly across the electrode.
Corroded, loose, or damaged wiring and connectors in the cylinder 1 ion sense circuit can cause a low voltage signal or high resistance.
If the vehicle uses a separate ignition control module, it may fail to process or transmit the ion current signal correctly.
An internal failure in the ECM is rare but can cause an incorrect low circuit reading if the internal resistor or monitoring circuit fails.
It is not recommended to drive extensively with this code, as it often indicates a misfire which can damage the catalytic converter over time and cause poor engine performance.
No, it rarely means the ECM is bad. Mechanics often mistakenly recommend replacing the ECM for this code, but the actual cause is almost always a failed ignition coil, spark plug, or a wiring issue.
It is a system that measures the electrical conductivity across the spark plug gap during combustion. This allows the engine computer to detect engine knock and misfires without using additional sensors.
The easiest method is to swap the cylinder 1 ignition coil with one from a different cylinder. If the code changes to the new cylinder, the coil is faulty. If the code stays at cylinder 1, the wiring or connector is likely the issue.