Hello!

Our son's 2013 XC90 is throwing 4 obd codes with the CEL on that seem to be related to something with the emissions control system. Car won't pass inspection with the CEL or codes so we are just trying to find out any information on what these codes could mean. I've researched a ton and can find information about what each individual code might mean, but not sure if they are all related or indicating multiple individual problems.

The car does have 175k miles on it. Here are the codes:

po420
po151
po128
po154

Thanks for any insight!

 

The P051 and P0154 are telling you there's a signal issue with bank 2 front O2 sensor. The P0420 is a cat converter efficiency code that is set because the ECU is comparing the front and rear O2 sensor signals and the front's out of wack. The P0128 code is for a faulty thermostat or engine coolant temp sensor. Probably best to replace both the t-stat and ECT sensor and then check the connectors/wiring for the bank 2 front O2 sensor and consider testing/replacing if the wiring looks good.

 

Thank you! That information is super helpful in pulling together the information on the different codes and making sense of them!