I have been troubleshooting my 94 Volvo 850 Turbo Wagon and find that I am not able to read any codes off of the OBD2 diagnostic unit in the engine compartment. When I set the test lead in the A-6 pin location & press the test button, the LED comes up red for as long as I depress the test button but once released shows nothing. I have also tried the procedure for clearing codes (hold the test button down for five seconds) and still nothing.

I have the check engine light on and knew to replace the oxygen sensors(which I have done) and now want to take it in for an emmissions test but the check engine light is still on and I need it off to be able to be tested.

Any advice out there on this?
Signed, Troubled in Oregon

 

OBDI port btw. What directions are you using for it? There are specific sequences to operate it.

 

The instructions here are pretty good; try it again.

 

If all else fails, take it to AutoZone or somewhere & ask them to clear it. You may also want to get a defferent code reader.