Engine Codes

[Vettn71]

Pulled codes on my 1995 GT

332 -EGR opening not detected
536 - Brake switch not changing state
632 - Overdrive switch not changing state

I've got a new EGR valve and position sensor. I don't think the EGR is working correctly, because when the car warms up at part throttle the light comes on; just when I'd expect the EGR to open

The other two codes don't make sense, as my brakes and lights work and my OD seems to be okay.

Anyone she'd some light on these?

TIA.

Jim

 

[Chythar]

The EGR is run via engine vacuum, so you may have a break in the line. The plastic vacuum lines are easily broken; they get brittle as they age. Also, it's really easy to hook up the wrong vacuum hose to the EGR; make sure GREEN is on the EGR, and RED is on the intake manifold. If one or both of those vacuum hoses is black rubber, someone has replaced broken parts of the hose. Trace the hoses back until you get to the plastic and see the original color.

The other codes may mean nothing; you have to press the brake and the overdrive switch during the KOEO test, or you'll get those codes. If you have a higher-end code reader, they'll tell you when to press both. Otherwise, it's difficult to tell when it's time to hit them during KOEO.

 

[Vettn71]

Chythar

I appreciate the info on the KOER test. I read the codes using a paper clip, so it didn't tell me anything :0)

I did find a good write up on troubleshooting the EGR system, so I hope to run through it next week. Odd thing is the car runs great, idles smooth and exhibits none of the usual symptoms; no pinging, loss of power at all. Just the light.

Regards
Jim

 

[jozsefsz]

It's also possible the EGR valve actuator itself has gone bad. You can test it by hooking it to direct manifold vacuum with the engine running, and it will stall if it's working. If it's broken you may hear it leak the vacuum and have little if any change in how the engine is running.