O2 Sensors
 

I have a 1999 Boxster with 54,000 on the clock that I picked up in February. Car is running fine but the check light came on the other day, all o2 sensor codes P0151,p0131,po157 and p0137.

I have no maintenance history on the car. Something tells that all four cannot be failing at once. The car is running fine, no performance issues.

I may check all the connections, but is there something else I should be looking at? Any thoughts?

Those codes indicate "short to ground" on all four sensors. Possibilities:

Sensors were replaced and mis-wired/wrong sensors
harness is damaged (rodents, heat from contact with aftermarket headers)
DME is failing

Yes, odd messages. I would recheck the electrical grounds, reseat all the connectors, reset the codes, and see if they reappear.

-Wayne

Thanks
 

Thanks for your help. Wayne, love your book, you have already saved me at least $1,000 bucks in repairs.