Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Originally my CAT and resonator went bad so I replaced the entire exhaust system along with a new o2 sensor, sensor 2. Since the entire replacement of the exhaust system was done two weeks ago the code P0054 comes up on a morning cold start, ONLY EVERY OTHER MORNINGS! When the P0054 comes on in the morning I clear it and it won't come back on until the second cold start( two mornings or 48 hours from the time of clearing the code). This happens consistantly, P0045 every other morning.
I had a garage check the o2 wires and connection and was told the wire loom on each side of the connector looked good, not against exhaust pipe, broken wire , etc.
BTW, I read something about clearing the codes before installing new o2 sensors. The code for the CAT may have not been cleared before the replacement of the exhaust system. Could this be a contributing factor? Also the weather temp. has been consistant the few weeks, no extreme climate changes.
I'm having a hard time understanding how a possibly bad o2 sensor can cause a P0054 only ON EVERY OTHER MORNING. I am going to check the heater resistance of the o2 sensor? Should the resistance be about 5 or 6 ohms? If the resistance is good what could be causing this every other morning P0054 code? PCM?
More info: Yesterday was the morning the code was to come up again, but the night before I pulled off the positive cable of the battery for a few minutes and reconnected it. So by removing power, the code P0054 did not come on yesterday morning but it did come up this morning so the problem is still there. Don't know if that helpful or not.
That is a heater resistance code. The PCM may only check the resistance at a cold start and it is likely a 2 trip fault. So you clear the code and it takes 2 cold starts to set the code again. Check the heater resistance.
Conditions for Running the DTC
P0054
The ignition is OFF for more than 10 hours.
The engine coolant temperature (ECT) Sensor parameter is between -30 and +45°C (-22 and +133°F) at engine start-up.
The difference between the start-up ECT and the intake air temperature is less than 8°C (14.4°F).
The system voltage is between 10–18 volts.
This diagnostic runs one time per valid cold start when the above conditions are met.
Conditions for Setting the DTC
P0054
The PCM detects that the HO2S heater calculated resistance is not between 21.2–8.8 ohms at engine start-up for 1 second.
Topic Author
