There is no Check Engine light with the key on engine off?

GARY49

MEMBER
1998 GEO TRACKER

I went thru local emissions and failed. The main reason being that there is NO Check Engine light with the key on engine off. Ive only had the car for a short time and have never noticed a check engine light. It also showed P0135 ( 02 sensor heater circuit malfunction-Bank 1) P0340 (Camshaft Position Sensor Circuit Malfunction) P0500 (Vehicle Speed Sensor Malfunction). I recently had a oil leak fixed and the battery was unhooked for this procedure. My questions would be: Is there a particular fuse path I would search out that would cause there to be no Engine Light and is it possible that the same wiring problem has caused all the problems. It starts good and gets to normal operating temp just fine and drives down the road just like everything is normal. I checked the fuse box under the hood to the best of my ability and the fuses appeared to be good. There was no fuse in the ABS slot but when I put a good one into the slot it didn't make a difference so I am guessing that it doesn't need that fuse. Any Suggestions?

1 Reply

DANNY L

MECHANIC
5,648 POSTS

Hello, I'm Danny.

Yes, when having a smog test performed the person has to verify the check engine light illuminates prior to performing any testing. I could be a simple burned out bulb in the cluster. I've attached picture steps below on how to remove the dash trim and cluster so you can access and replace the bulb in the cluster. Here is are a few tutorials for you to view regard the codes you mentioned:

https://www.2carpros.com/articles/camshaft-angle-sensor-replacement

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

I've also included diagnostic picture steps below for the 3 codes (P0135, P0340, P0500) you mentioned in your post relating to your Tracker. Hope this helps and thanks for using 2CarPros.

Images (Click to make bigger)