1997 S70 T5 stock boost pressure?

[Vuym]

Both those codes are for the downstream sensor on the cat. How do you not have one on your car? Did you have it removed? If it is not there it will throw a code and in these cases for readings out of spec.

Neil.

So when I bought the car, the catalytic converter was supposedly stolen few days prior along with the rear O2 sensor. Can I fit in any P80 O2 sensor to replace it or does it need to be from an S70? Could these codes potentially be limiting boost when the TCV has all its vacuum lines in place?

[scot850]

There will be one for your car but any turbo should work. However, if I recall correctly the part numbers changed in 99. They were made by Bosch, just watch out for copy parts labelled as Bosch. So buy from a good supplier. Again double check as some of the rear O2 sensors had a short connector harness, but I can't recall if your does or not. If you plan to replace the sensor, check before trying to fit that the connector is correct and it is long enough to reach whatever connector your car still has.

It could limit the boost, but my understanding of these earlier cars is the rear one really just confirmed what the front one was doing was correct.

Is your temperature gauge working correctly? Another age related issue is the ECT (coolant temp sensor mounted by the thermostat) either going out of spec or failing. There are resistance values you can check at ambient temperature to confirm the unit is recording correctly. If it is not, the car can run over rich. Check the connector at the back of the power steering pump is not crumbling or the wiring or connectors into and out of it.

Is your IAC valve working correctly? They also get sticky and can cause running issues.

Neil.