ECM going out or gremlins?

[HSLD]

Every few months, I get a check engine light on my Classic, or the cruise won't work on a trip or some other gremlin rears it's ugly head. I had it checked out by a couple of shops and we cannot find anything wrong. The ECM checks fine. I check the fluid levels and other obvious items when I get the "light" on the road and they're all fine. Had a driver tell me the other day that it's a good sign that my ECM's fixing to go out. Guess my ECM's has been going out for about a year now becasue that's when this started.

Anyone got any ideas?

HSLD

[Chiefwhatdahey]

Clean all your grounds including the cab ground dirty ground connections cause funky codes and fool people into spending more $'s than they should.

I also remove the ground strap from the starter solenoid to the outer case this is a good source of corrosion that fools owners into buying a starter when they didn't need to.

[Capt._Chaos]

Clean all your grounds including the cab ground dirty ground connections cause funky codes and fool people into spending more $'s than they should.

I also remove the ground strap from the starter solenoid to the outer case this is a good source of corrosion that fools owners into buying a starter when they didn't need to.

In addition to the above, I'd suggest:

*Finding out what fault codes are in the ECM. If a few of the same are in there, then it's an indicator that the sensor in that particular circuit is going out.

*Removing the connectors to the ECM and checking the rubber seals for pliability, and to make sure water is not getting into the connectors. If moisture is present, it can & will wreak havoc on the ECM.

*Check the power feed harness for the ECM that connects directly to the batteries. Usually also has a ground wire that can get corroded and cause problems.

[LSMR]

What year truck & what make engine?That might help us figure this out.

[Chiefwhatdahey]

Clean all your grounds including the cab ground dirty ground connections cause funky codes and fool people into spending more $'s than they should.

I also remove the ground strap from the starter solenoid to the outer case this is a good source of corrosion that fools owners into buying a starter when they didn't need to.

In addition to the above, I'd suggest:

*Finding out what fault codes are in the ECM. If a few of the same are in there, then it's an indicator that the sensor in that particular circuit is going out.

*Removing the connectors to the ECM and checking the rubber seals for pliability, and to make sure water is not getting into the connectors. If moisture is present, it can & will wreak havoc on the ECM.

*Check the power feed harness for the ECM that connects directly to the batteries. Usually also has a ground wire that can get corroded and cause problems.

Not to step on any toes but unless HSLD knows what he's doing I wouldn't reccommend touching the ecm harnesses, he could end up calling a wrecker.

[HSLD]

What year truck & what make engine?That might help us figure this out.

1999, Detroit Series 60

HSLD

[HSLD]

Clean all your grounds including the cab ground dirty ground connections cause funky codes and fool people into spending more $'s than they should.

I also remove the ground strap from the starter solenoid to the outer case this is a good source of corrosion that fools owners into buying a starter when they didn't need to.

In addition to the above, I'd suggest:

*Finding out what fault codes are in the ECM. If a few of the same are in there, then it's an indicator that the sensor in that particular circuit is going out.

*Removing the connectors to the ECM and checking the rubber seals for pliability, and to make sure water is not getting into the connectors. If moisture is present, it can & will wreak havoc on the ECM.

*Check the power feed harness for the ECM that connects directly to the batteries. Usually also has a ground wire that can get corroded and cause problems.

No fault codes, that's the kicker. No moisture in the connections and the connections are clean.

The "light" has almost come to be the little boy that cries wolf. I'm not saying I ignore it, I'm not overly concerned with it like I was at first. I'd just like to know that when it does come on, it means something is wrong and not some gremlin showing up.

I can't help but think it's some little nit noid thing we're overlooking.........

HSLD

[LSMR]

I had a fleet with the 60 series that were around the same year as yours.Their was a period when some of the computers were not sealed correctly and moisture would get inside them.We had to replace 2 computers because of this.A good detroit shop can determine this.The detroit shop in our area is Penn-Diesel.They are not a truck dealer they only work on detroit/allison products.

[Chiefwhatdahey]

If you're not getting a code of any kind then it very well could be a connector or a sensor is getting moisture. Does the light come on when it's wet, humid or after the truck has been washed? if so then that could be your problem. Take a garden hose and douse your ecm first (don't force spray) watch your dash to see if the light comes on do this at all connections you can find, once again I wouldn't remove any plugs concerning the ecm as you might end towing the truck to the shop. good luck.

[HSLD]

If you're not getting a code of any kind then it very well could be a connector or a sensor is getting moisture. Does the light come on when it's wet, humid or after the truck has been washed? if so then that could be your problem. Take a garden hose and douse your ecm first (don't force spray) watch your dash to see if the light comes on do this at all connections you can find, once again I wouldn't remove any plugs concerning the ecm as you might end towing the truck to the shop. good luck.

I'm thinking humidity is probably what the problem is.