Honda motorcycle fault codes and warning indicators, with meanings, causes, and step-by-step fixes.
121 models · 12 error codes
On Honda motorcycles and scooters, PGM-FI code 1 means the ECM has detected a fault in the MAP (manifold absolute pressure) sensor circuit — the sensor that reads intake pressure so the ECM can set the right fuel and ignition.
On Honda motorcycles and scooters, PGM-FI code 7 means the ECM has detected a fault in the ECT (engine coolant temperature) sensor circuit. The ECM uses coolant temperature to enrich the mixture on cold starts and to manage the cooling fan.
On Honda motorcycles and scooters, PGM-FI code 8 means the ECM has detected a fault in the TP (throttle position) sensor circuit — the sensor that tells the ECM how far the throttle is open.
On Honda motorcycles and scooters, PGM-FI code 9 means the ECM has detected a fault in the IAT (intake air temperature) sensor circuit. The ECM uses intake air temperature to fine-tune fueling for air density.
On Honda motorcycles and scooters, PGM-FI code 11 means the ECM has detected a fault in the VS (vehicle speed) sensor circuit — the sensor that reports road speed to the ECM and speedometer.
On Honda motorcycles and scooters, PGM-FI code 12 means the ECM has detected a fault in the No. 1 fuel injector circuit — the injector that sprays fuel into the intake for that cylinder.
On Honda motorcycles and scooters, PGM-FI code 21 means the ECM has detected a fault in the O2 (oxygen) sensor circuit. The O2 sensor lets the ECM trim the mixture for clean, efficient running (closed-loop).
On Honda motorcycles and scooters, PGM-FI code 29 means the ECM has detected a fault in the IACV (idle air control valve) circuit — the valve that meters air to hold a steady idle.
On Honda motorcycles and scooters, PGM-FI code 54 means the ECM has detected a fault in the bank angle (tip-over) sensor circuit. This safety sensor cuts fuel and ignition if the bike falls over.
On Honda motorcycles and scooters, PGM-FI code 18 means a fault in the camshaft position (CMP) sensor circuit — the sensor that identifies the cylinder cycle for injection and ignition timing. The engine typically won’t start.
On Honda motorcycles and scooters, PGM-FI code 23 means an open or short in the oxygen (O2) sensor heater circuit — the heater that brings the O2 sensor up to temperature. The engine usually runs normally.
On Honda motorcycles and scooters, PGM-FI code 86 means a serial-communication fault between the ECM and the instrument cluster/gauge — the two aren’t exchanging data correctly.
These codes apply across Honda models, including:
