Error codes after replacing O2 and MAF sensors

[JFP in PA]

Originally Posted by dbeesley1

Hi, I still get the following 4 codes after replacing all 4 O2 sensors and the MAF sensor:

P0151
P0131
P0157
P0137

After replacing all 4 O2's, I took for a test drive and the water pump failed. After getting towed to the dealer, they told me the MAF sensor was faulty. I just replaced it and I still get the 4 codes above.

Any recommendations on next steps?

Thanks,
David

I’m not surprised; all four codes are indicative of all four o2 sensors being shorted to ground, which usually points to a wiring issue, not the sensors themselves. And none of these codes point to anything to do with the MAF.

When one O2 sensor throws a code, the first thing you should do is test the electrical diagnostics of the sensor, which requires about 5 min. and a digital multi meter to test voltage, continuity, etc.; the sensor does not even have to be removed to do this.

When all four O2 sensors throw the same codes at the same time, you need to be circumspect; the probability of all four dying the same way and the same time is lower than wining the lottery, it just does not happen; something else is involved. In this case, either the wiring or the DME have a problem; changing out about a grand’s worth of parts is not going to change that fact; you need to look further……………