code 12

[VIPER1988]

i know it means egr lift sensor. but the light does not come on till after 15-20 mins of driving. and goes off every time i turn off the car. also i have a huge vacuum leak, sounds like it might be coming from egr valve. leak is big enough that it can be heard over the engine running. is the lift sensor attached to the egr valve or separate. and why would the light go out and not come back on till 15-20 mins of driving?

Thanks

[Nafs Asdf]

i know it means egr lift sensor. but the light does not come on till after 15-20 mins of driving. and goes off every time i turn off the car. also i have a huge vacuum leak, sounds like it might be coming from egr valve. leak is big enough that it can be heard over the engine running. is the lift sensor attached to the egr valve or separate. and why would the light go out and not come back on till 15-20 mins of driving?

Thanks

I think the EGR doesn't come into function until the car is warmed up, and I guess it's then that it notices it malfunctioning. The CEL is supposed to go off when you shut the car down.

[88LXi68]

The CEL is supposed to go off when you shut the car down.

But the code is stored in the ecu and until the problem is fixed and the ecu reset it will continue to display a CEL

[Nafs Asdf]

Yes the code will be stored, but the light won't go on until it detects something wrong again. That's how mine works at least.

[VIPER1988]

even if the engine is already at operating temp. if i turn it off then back on the light wont come back on for 15-20 min.

[Dr_Snooz]

It's always a good idea to fix what you know to be broken (like vacuum leaks) before trying to troubleshoot further.

[VIPER1988]

replaced egr valve. didnt change anything. inspected all vacuum hoses that i could see, none of them are dry rotted or cracked. its a huge vacuum leak somewhere in the area of the egr valve. cant figure out exactly where its coming from.

[88LXi68]

how do you know there is a vacuum leak? did you spray brake cleaner in the area and the car stall?

if you haven't done so make sure you reset the ecu after repair work

[VIPER1988]

yes im sure there is a leak. it can be heard over the running engine. i unhooked battery while i was changing the valve, which took about 30 mins.