ECM going bad? More LP problems.

Cozze44

Cozze44

Junkman
Joined
Feb 9, 2012
Messages
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Lift pump is plaguing me again... Had my pump stop running Sunday while I was at the flea market. Ended up cutting a piece of wire out that wasn't needed to drive and made a jumper to get home. I dug into it yesterday. Went through the fuses, and relays. Found that I wasn't getting any power from the harness to engage the LP relay. I have tested for power right out of the computer yet, to see if there is a break in the wire. Crossing my fingers that there is. If not, is it a sign the ECM is going bad. I have had more and more issues lately that may all point to the same thing. No LP, No Cruise (checked, and all vacuum is fine), and I get no boost reading on my Edge box. Anyone have a similar issue?
 
ECM. 9/10 times (yes that is an exact figure LOL) when more than one feature/function/sensor whatever it is stops working all of a sudden the ECM is the issue. The other times it is usually the engine harness had gotten diked up severely and quite obviously to the naked eye.
 
I have one out of a 2001 SO auto if an ECM is what you need. But just make sure you have 12v power to the ECM on both wires. I believe its pins 48 and 50
 
Thanks guys, I'm gonna see if I can pick one up local to throw in there quick to see if it is my issue. If I can't, i'll pin it out, and make sure I'm not wasting my time before I buy one on here.
 
why not just wire it to a key-on 12v... and not worry about it.
 
Mudn_1 said:
why not just wire it to a key-on 12v... and not worry about it.
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My guess is because if it is in fact the ecm he would rather not be stranded if the ecm takes a dump all together.
 
I get that. I have seen time and time again... a single driver go down in the ECM and not effect the truck otherwise... Not saying its not on its way out, but It might be fine.
 
Mudn_1 said:
I get that. I have seen time and time again... a single driver go down in the ECM and not effect the truck otherwise... Not saying its not on its way out, but It might be fine.
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Because i'm tired of have no cruise, boost gauge, and I just want it to be right.
 
Cruise control is controlled by the PCM. MAP sensor is hooked the ECM. Then Thee lift pump is directly signaled from ECM. You might have to check your clock spring for damage in the steering column.

Being there is several subsystem failed I would have the alternator tested for excessive AC noise. 0.1 AC Volts is a fail. 0.01 to 0.02 AC Volts is normal for alternator.

https://www.youtube.com/watch?v=MGaHaIXZioA
 
Finally I got lucky, cleaned ECM plug out, put it back together, hot damn! Good to go. I never get that lucky!
 
Cozze44 said:
Finally I got lucky, cleaned ECM plug out, put it back together, hot damn! Good to go. I never get that lucky!
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Now THAT is rare and lucky. Usually ECM plugs stay quite clean and dry. IIRC these use a deutsch made plug that is similar to the ones used on the larger cummins engines? If so look for any empty pin spots missing plugs. Or the seal the pins push through isn't quite doing its job anymore.

Congrats though. Always a good feeling.
 
Mudn_1 said:
I get that. I have seen time and time again... a single driver go down in the ECM and not effect the truck otherwise... Not saying its not on its way out, but It might be fine.
Click to expand...

Happened to mine. Lift pump circuit quit but the rest worked great. Happens quite often actually.
 
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