Well, spring is in the air, and I brought the car outa storage to do some work on it, before it hits the road.. now the car has been sitting dormant since the beginning of november, and when I put the battery in and fired it up, the ECM light came on for a while, then went off, and doesn't come on again, and it shows no error codes, just 12 which is ok.. any thoughts as to why it would come on like that in the first place?

 

FastE,

That "ECM" light is actually a Malfunction Indicator Lamp (MIL). There can be several things that set will force the lamp on without setting a permanent Diagnostic Trouble Code. A load such as the EGR solenoid, EVAP solenoid, injector, fuel pump relay, etc., may have been out of the tolerance range for whatever reason. Even a MAF signal that was out of the acceptable range can turn on the lamp and not set a DTC. It is possible that the MAF hot wire had "junk" accumulated on it from storage and didn't allow heat to radiate off the wire, causing a low MAF flow error. Once the wire became heated to the operating temperature of 75°C above the incoming air temnperature, the "junk" may have burned off. Any number of loads may have had a marginal connection that was "cured" when some current started to flow.

If it ain't broke, you can't fix it. Or a better quote from a former associate, "If it ain't broke, fix it until it is."

When you first turn on the ignition, and before cranking the engine, watch the MIL. It should turn on briefly, go off briefly, then turn back on and remain on until the engine is running. This lamp "bounce" indicates that the ECM has passed some rudimentary self-diagnostics. Part of this diagnostic is checking whether there is a valid EPROM installed, whether the loads are connected, and some firmware checking on the output transistors and input converters.

It is certainly is a good thing that you checked it out, but if the condition doesn't recur, I wouldn't lose a lot of sleep over it. Just make a note of it in your service record in case something related happens in the future.

I presume everything else is operating normally?

 

Thanks Vader... actually back in the fall, there was a problem starting to develop with the engine Temperature sensor, perhaps it is finally thowing a code.. I plan on repacing that sensor in the next week anyways.. But since I don't have a Mass Air Flow Sensor anyways.. the only other one I could check is the one in the air cleaner..

 

Fast,

OOPS! I guess I need to slow down a read a little more thoroughly. I caught the "89" part, but didn't pay any attention to the "L03" info. Obviously, forget about the MAF idea.

If you suspect the CTS, you can meter it easily. If you feel it is an intermittent problem, they're only about ten bucks and it would be a great excuse to flush and drain the cooling system. If your system is really tight, it may also be a good excuse to switch to Dex-Cool for maximum corrosion protection during those storage periods.