Engine codes P1166 and P1167 codes on 2001 Honda Accord

Question

Have both P1166 and p1167 codes. I can't see both O2 sensors going out at the same time. I also have low RPM at idle in gear (idles fine without load), valve train noise on the number 4 cylinder, and hesitation on acceleration. The car runs great while driving but almost dies at a stop light/sign. Could these codes be due to something else (i.e. blocked cat, tps, bent valve, etc.)? I am repairing it for a friend trying to sell it and doesn't have a lot of money. I have checked/replaced all fuses, and relays.

Answer 1

Hi there

Both of these codes point to an issue with the front O2 sensor heater circuit. This is only one sensor and typically when the heater circuit fails, it is due to the sensor.

P1166 HONDA - Air/Fuel Ratio Sensor 1 Heater Circuit Malfunction
Read more: https://www.autocodes.com/p1166_honda.html

P1167 Honda Code - Air/Fuel Ratio Sensor 1 Heater System Malfunction
Read more: https://www.autocodes.com/p1167_honda.html