2004 Honda Civic Si Q&A
2004 Honda Civic Si Question: after replacing 02 sensor check engine light still on.
First it is not a O2 sensor. It is a Air Fuel Sensor. It is the upstream sensor. P2252 Air Fuel Sensor (Bank 1 Sensor 1) VS Line Low Voltage - With Automatic TransmissionPossible Causes Setting Conditions AFS1 connector is damaged (check pins for damage, and for moisture) AFS1 VS circuit is shorted to ground AFS1 has failed (it may be contaminated with fuel, silicone or water) Update the PCM to the latest software. If the code remains, substitute a known good PCM and retest. If the problem goes away, the original PCM has failed. Engine running; and the PCM detected an unexpected low voltage condition on the Bank 1 Air Fuel Sensor 1 (AFS-11) VS circuit. This code sets in 1 Trip(s). This code will turn on the MIL (Malfunction Indicator Lamp) - EXPERTEC
after the correct repair is made, the repair tech will clear the light and do a drive cycle to verify the repair. Roy - mastertech6371