Hi,

I just had engine replaced with used engine with 38M K, on my 199 S70 AWD.

Check engine light is on with code reading rear O2 sensor.

It seems strange as this was not the case before.

Installer (Volvo/Audi Specialist) is very good, chcked to with Ohmeter or something
to make sure no wires were broken, chcked out ok.

Will this go away as the engine is not running rich as before, or
is it a coincidence, and the O2 Sensor just happened to go at this particular moment.

Any suggestions apreciated.

Thanks in advance.

Ted

 

Hi Ted,

The O2 sensors on Volvos & European cars are notorious for premature failure (Bosch). Also, even if they are fine, they can trigger CEL for very trivial reasons, such as neglected tune-up that is causing less-than-perfect combustion.

I would go over the ignition components (plugs, plug wires, distributor cap & rotor, dump a large bottle of Techron fuel system cleaner into the fuel tank, check/replace air filter, fuel filter, etc...). Also, make sure that the EGR &PCV systems are in good working order, and clean the throttle body if you can.

I hope this gets you started.

Cheers,


JPN