Hi,
I got a Code P0172 today, that translates as a system to rich Bank? What's it telling me Internet says it coulgd be a MAF sensor or an unhappy O2 sensor.

I think I'll turn it off first as a test to see if it goes away or not. Any other Troubleshooting tips?

TIA ,
Woody

The probable cause is a leak of un-metered air into the intake manifold, the extra air causes the engine to run rich. Running rich destroys the front O2 sensor by coating it with unburned gasoline.

True, you could have a dirty MAF, but that gets expensive. Same with the front O2 sensor. Check for vacuum leaks first, it is cheaper and usually the cause.

Klaus
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Two great Volvos, a 1967 220 and a 1998 V70R

Is there an equivelent Service manual printed like the 740 Haynes? if so Where do I get it?. I'm a visual guy and I'd lke to have a referance book to find these Vacum hoses?

Tia

Woody

The Haynes 850 book is pretty good for the 850, but there are many differences - like door panels, rear brakes, etc.

For vacuum hoses, I just mean any hose that comes from the intake manifold, plus the PVC system hoses. A turbo has additional hoses. Even a diagram is not complete for all models, Volvo tended to change the routing of the vacuum hoses every year.

Klaus
--
Two great Volvos, a 1967 220 and a 1998 V70R