[Otto]

at the end of the first day of the first de this season, the cayman developed a check engine light

open circuit, o2 sensor, driver side

chapman did a leak test. tested the o2 sensors, finding one "slow". they replaced all four o2 sensors.

almost immediately got the check engine light again, and the same code

gary baker thinks it could be the cats are bad and need replaced

chapman now thinks there is a short in the wire harness between the o2 sensors and the ecu.

i am at a loss as to what to do now.

any ideas my friends?

otto

[cmartin]

testing wire for the short should be simple, I would do that first. Just get a pinout of the ecu connector and a multimeter.

[Otto]

Originally Posted by cmartin

testing wire for the short should be simple, I would do that first. Just get a pinout of the ecu connector and a multimeter.

chapman tested the harness, and claims to find a short

not sure why a short would simply appear out of nowhere

now i am looking at exhaust systems as well, and i don't care for the numbers on that at the moment

[BlackTalon]

If it is a shorted wire, what do you hope to accomplish by replacing the exhaust system?

[cmartin]

while you're in there....

[BlackTalon]

That is definitely an odd "while you are in there item. You are typically talking about a couple thousand just for the new system (not including install). Only usually worth it is it has been shown that the stock system is hindering power.

[cmartin]

Its a slow day, trying to come up with something. I generally like to replace only whats bad, that seems so old school today.

[BillC]

Bad cats would not cause an "open circuit" error code. So, there's a good chance it really is a short.

And, intermittent shorts can be one of the hardest and most annoying problems to track down.

[trytryagain]

Wouldn’t the cats still be under warranty?

[tbernard]

Originally Posted by trytryagain

Wouldn’t the cats still be under warranty?

should be, emissions warranty is 8 years or 80k miles. If race gas has been used they could argue running at the track has burned them out.