1993 Chevrolet Lumina coupe z34
The check engine light has been on for a couple months but I haven't had the money for any repairs so I let it go. Well, now it's emissions time.
So I covered the check engine light with a picture of my nephew
and took it in.
Here are the results...
Code:
| my emissions | applicable standard | result
HC | .31 | 1.00 | pass
CO | 4.37 | 12.00 | pass
NOx | 2.88 | 2.50 | fail
After some research on the internet I found a whole list of things it could be. I also found out how to check for error codes without a reader.
The codes I got are 15,32,42 (are those the numbers from lost?).
According to the trouble codes website.
15 - Coolant temperature sensor signal indicates a temperature colder than -37 F when the engine was running.
32 - EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas.
42 - The EST signal did not change when the ECM applied bypass voltage to the ignition module.
My questions.
1. -37 f doesn't seem too likely considering I live in Arizona, must be a bad sensor. Where is it?
2. Seems the EGR valve is bad. Is there a way to test it (digital EGR) like you can the vacuum type?
3. Is there a sensor for the EGR that may be the problem? If so, where?
4. Any help with the error code 42.
Thanks for any help.