ECU Hiccup

[UberRoo]

My check engine light came on the other day. The car had been sitting all night and it didn't want to run when I tried to start it. It cranked and cranked for a while, kicking and coughing, but my battery didn't last very long because I had been running my stereo with the engine off for quite a while the night before.

So I hooked my gadjillion amp charger up and kept cranking, because after all, it was at least trying to run with all the kicking and sputtering it was doing. When it finally started up after about a cumulative minute of cranking, the engine light was on. Later in the day, around lunch, it started just fine, but the light remained. The next morning however... With a cold engine, it didn't want to start.

I pulled the codes and got 21, engine temperature sensor, and 34, EGR solenoid. Well, code 21 explained why the cooling fans were both running even with a stone cold engine, but I had just replaced the temperature sensor. Anyway, I replaced it again with the sensor from my other SVX, which has no codes or trouble lights.

The problem was still there. So, just on a whim, I reset the ECU because I was down there playing with the wires anyway. Ha! The trouble light goes away, and it starts on the first crank. WTF?! The 'problem' didn't even exist. The 'problem' wasn't causing any troubles, the ECU was causing my headache! How 'bout that?

My conclusion is that the low battery from running the stereo caused the ECU to go stupid. For some reason, it did more than just store imaginary codes, but also screwed with it's engine management protocol. It's been running fine for a while now.

I thought you guys would appreciate knowing that gremlins do exist.