Engine light on when car off/Fuel Pump goes on and off
 

My 2004 Saturn Ion Quad Coupe 2.2 Liter has a strange problem. I noticed it the other day when I went to start it and the battery was dead. I charged the battery and noticed the yellow engine light was on when the car was off. I started the car and the light went off. When I turned the car off, the light went back on, then within a few seconds I heard a click under the dash (fuel pump relay) and the fuel pump would turn on for a few seconds then turn off. It would turn on again a after about 5 seconds and turn off again, and continue doing this, which apparently is what killed the battery. Since the battery was 6 years old already, I replaced it with a new one and the problem continued. After doing some research, and since the fuel pump relay is controlled by the ECM, I bought a matching used ECM on EBay for $19. I installed the new ECM, retrained the security pass code and the car started fine. When I turned it off, there it was again, the engine light went on and the fuel pump started its on and off thing again. Each time it goes on and off I hear the relay click. After more research I am thinking it might be a faulty oil pressure switch signaling the engine is running causing the fuel pump to operate. This is a problem in other vehicles, but I am not sure if the Ion is wired this way. Any thoughts on this?

So look in the owners manual or look it up on the internet and see what light it is. Why, because we have no idea what light came on.

Sorry, I figured "Yellow Engine Light" was descriptive enough but apparently not. Perhaps there are other yellow engine lights on the car I am not aware of which caused the confusion. It is the yellow light in the shape of an engine on the instrument panel next to the speedometer that typically turns on when problems with a system are detected. In this case, it only goes on when the key is in the off position and the fuel pump keeps going off and on. A symptom not described in the owners manual or could be found on the Internet after an extensive search. The closest thing I could find was a possible short in the wiring to the pump, or even a stuck OIL pressure sensor which signals the fuel pump relay to power the fuel pump once the vehicle is started and pressure is detected indicating the engine is on and is need of fuel. After starting the OIL pressure sensor signal is responsible for activating the fuel pump relay and the ECM is by-passed. The ECM only trips the relay during start-up. Other GM vehicles are configured this way, but I am not sure if the Ion is and was hoping someone could tell me, but I am going to disconnect the oil pressure sensor and see what happens and if nothing else, eliminate it as the culprit.

Stop in the new member area and introduce yourself. Once done with that open the USER CP top left of most pages and add your first name location and car info to your signature......

THANKS.

That is something that I've never heard of , but then again, Saturns do have their unique "quirks" that seem to be exclusive. Sounds like you're on the right track with disconnecting the OPS to start with. It does seem to have to be an electrical problem. You don't state how many miles you have on it, and even though it's not common, OPS do get flaky or short out sometimes. Let us know if unplugging it has any effect. I'd try replacing it if it were me. Where in the world did you find the info about the OPS having that effect on the starting system? I'm just curious.

Thanks for responding. I couldn't begin to guess where I got the OPS info, but they came up in a Google search. I believe it was from a Chevy S-10 forum, and a GMC truck forum. As it turns out, the OPS is not the culprit, but I think I found it. I discovered a second clicking under the dash besides the click from the fuel pump relay. During my several engine on/off cycles during my testing, the infamous "power steering" warning appeared on the message display. The power steering had never had an issue, however, the message just started. The secondary click (after the engine was off) was coming from the control box on the power steering assist motor. I unplugged the wire connectors from the box and no more clicking, no more check engine light, no more fuel pump running. I am guessing a fault in the power steering system was somehow energizing the the fuel pump relay...perhaps one of those exclusively Saturn quirks you referred to. Fortunately, GM extended the coverage to 150,000 miles for the power steering problem.

I had no idea there even was a power steering assist motor. Learn something new every day! Hopefully, you'll find a Saturn friendly GM dealer that will take care of that for you. Let us know what happens. Nice job trouble shooting too!