My car spit out 8 codes the other day i replaced 1 out of 4 o2 sensors, cleared the codes and now it is only spitting out 4 codes but still the same 4 as last time.
(P0135) o2 sensor heater circuit malfunction Bank 1 Sensor 1
(P0141) o2 sensor heater circuit malfunction Bank 1 Sensor 2
(P0155) o2 sensor heater circuit malfunction Bank 2 Sensor 1
(P0161) o2 sensor heater circuit malfunction Bank 2 Sensor 2
Why would it still be saying ther is a problem with all four sensors even though i just replaced one?
And what would be causing all of the sensors to be malfunctioning like this?
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Voltage low on cam sensor ,how do you know that ? Is there a DTC - diagnostic trouble code associated with this ? Low voltage codes usually indicate an open on the circuit . Camshaft Position Sensor Circuit Quick Test
DTC P0171: Bank 1 system too lean. Probable cause:
1. Wire harness fault. Check for correct voltage, open, short to ground, short to voltage
2. Fuel pressure problem. Check pump, regulator, filter, lines
3. Exhaust leaks or restrictions
4. Vacuum leaks. Check for damaged hoses, incorrect routing
5. Fuel contamination
6. Incorrect sensor installation
P0171 is a lean Oxygen Sensor code. It is trying to tell you that your engine is running lean...not getting enough fuel, or getting too much air. That will cause the poor running and dying. This is most likely caused by a bad vacuum leak. The O2 heater code is probably caused by a failed O2 sensor heater. Sometimes it is caused by an open or short in the O2 sensor circuits, but most of the time it is the sensor itself.
I just got done replacing the O2 sensors in my 99 Cougar due to throwing a P0135 malfunction code. There's 3. Facing the engine there's one in the front coming off of the front header, which is easy to get to. Another more tricky one if between the engine and the fire wall on the rear header pipe. The third is under the vehicle behind the transmission pan on top of the exhaust. In order to replace the O2 sensor near the fire wall you will need to remove the 4 retaining bolts for the ECM module and move it out of the way. Additionally you will need to remove the 2 retaining nuts for a wiring harness that is seated below the ECM module. Pay close attention to the connectors because the front and under vehicle O2 sensors have round connectors the one near the firewall has a squared connector. I was able to replace all 3 by myself in approximately 35 minutes. If your throwing a O2 heater malfunction code it is most likely going to be the sensor near the firewall. make sure that you know someone with a code reader so the code can be cleared. If you're do for an emmissions inspection be sure to put at least 40 miles on the new O2 sensor with different types of driving (e.g. highway, coasting, decellerated turns and rapid acceleration). Gotta love project cars for your kids!!