Truck not shutting OFF after running in rain..
04-06-2022, (Subject: Truck not shutting OFF after running in rain.. ) 
Post: #1
Truck not shutting OFF after running in rain..
Hey guys..
2013 KW T660, CM2250, 13 speed.

After running in LOTS of rain yesterday once parked the engine wouldn't shut off with the key.
Ended up yanking the ECM fuse to shut it down. Several weird things...
The dash lights stayed on with key off, but radio and everything else powers down with key off. when I turn the key ON it doesn't go through all the clicking noises like it still had key on.. same when turned to acc.
Truck starts and runs fine though. Just have to pull ECM fuse to shut it off and it still has power like the key is on even with it in the OFF position.

Gonna rain all day again today too..

Will this clear up once it dries out? Where would I start looking for water that is causing this?

Thanks
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04-06-2022, (Subject: Truck not shutting OFF after running in rain.. ) 
Post: #2
RE: Truck not shutting OFF after running in rain..
I assume your truck has the same centre console as the t800/w900. The cab control unit (cecu)on these trucks as well as abs modules are inside it. Ive seen windshield leaks cause cecu controlled problems. If i remember right the water runs down the harness. I would pop the console out and inspect the plugs on it for moisture. Otherwise i would say possibly key switch issue and nothing to do with the rain. The key switch i believe is monitored by the cecu which in turn turn on the various ecm/systems. If u heard no clicking that would be a sign at least the abs control module wasnt told to shut off, along all the other modules including ecm[/align]. Id start by checking cecu for moisture, and proving key switch is operating properly
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 Thanks given by: Possmguts
04-06-2022, (Subject: Truck not shutting OFF after running in rain.. ) 
Post: #3
RE: Truck not shutting OFF after running in rain..
(04-06-2022 )Agentspd Wrote:  I assume your truck has the same centre console as the t800/w900. The cab control unit (cecu)on these trucks as well as abs modules are inside it. Ive seen windshield leaks cause cecu controlled problems. If i remember right the water runs down the harness. I would pop the console out and inspect the plugs on it for moisture. Otherwise i would say possibly key switch issue and nothing to do with the rain. The key switch i believe is monitored by the cecu which in turn turn on the various ecm/systems. If u heard no clicking that would be a sign at least the abs control module wasnt told to shut off, along all the other modules including ecm[/align]. Id start by checking cecu for moisture, and proving key switch is operating properly

Thanks, yes it does have the center console.. I'll get it apart and check it out.. I did however replace the ign switch last year because it was sloppy... but I guess that doesn't mean it couldn't be bad now I suppose.
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04-09-2022, (Subject: Truck not shutting OFF after running in rain.. ) 
Post: #4
RE: Truck not shutting OFF after running in rain..
I have not been able to find the problem as of yet.

It just wont shut down without pulling the ECM fuse. Then wont start unless I hotwire it.

When running its runs just fine, its not even trying to shut off with the key. or even with ignition switch unplugged. Just keeps on running. Not stumbling or anything, just run like normal and wont shut off or start without now unless I hotwire it.

Unplugged the 3 big plugs at ECM, cleaned with electrical cleaner and plugged back in. Changed nothing. Removed and inspected the CECM and found nothing.

This was not an intermittent issue, its just happened.

I have no Idea what to do.
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04-09-2022, (Subject: Truck not shutting OFF after running in rain.. ) 
Post: #5
RE: Truck not shutting OFF after running in rain..
(04-09-2022 )Possmguts Wrote:  I have not been able to find the problem as of yet.

It just wont shut down without pulling the ECM fuse. Then wont start unless I hotwire it.

When running its runs just fine, its not even trying to shut off with the key. or even with ignition switch unplugged. Just keeps on running. Not stumbling or anything, just run like normal and wont shut off or start without now unless I hotwire it.

Unplugged the 3 big plugs at ECM, cleaned with electrical cleaner and plugged back in. Changed nothing. Removed and inspected the CECM and found nothing.

This was not an intermittent issue, its just happened.

I have no Idea what to do.

are there any aftermarket gauges in the dash?.. boost and pyro?... if so then unplug them completely and see if the problem clears up. Maybe one of them is going bad and back-feeding power to somewhere it should not be. Seen that before.


User's Signature: ->: What I post is just my own thoughts and Opinions! --- I AM Full Of S__T!.
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04-09-2022, (Subject: Truck not shutting OFF after running in rain.. ) 
Post: #6
RE: Truck not shutting OFF after running in rain..
[/quote]

are there any aftermarket gauges in the dash?.. boost and pyro?... if so then unplug them completely and see if the problem clears up. Maybe one of them is going bad and back-feeding power to somewhere it should not be. Seen that before.
[/quote]

That didnt change anything...
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04-09-2022, (Subject: Truck not shutting OFF after running in rain.. ) 
Post: #7
RE: Truck not shutting OFF after running in rain..
Even with CECU all unplugged, still acts as if ignition is ON...
Really need some help with this.
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04-09-2022, (Subject: Truck not shutting OFF after running in rain.. ) 
Post: #8
RE: Truck not shutting OFF after running in rain..
(04-09-2022 )Possmguts Wrote:  Even with CECU all unplugged, still acts as if ignition is ON...
Really need some help with this.

If it is not the key-switch itself or its associated key-on relays(s), then What you will most likely find is that some device (gauge, controller, abs, dash radio, panel control, ... something...) that is wired to BOTH the +12 volts battery, AND the key-switch, that is back-feeding power from its battery circuit into the key-on circuit improperly.

The biggest offenders are usually something that did not come with the truck when it was purchased.. like aftermarket gauges, e-log devices, a hidden tracker from a leasing company, or anything else that someone has installed. That is why I asked if you had unplugged all your aftermarket gauges, etc. .. but it can also be an OEM device as well that is going bad.

===========
(last resort, when all the normal things that cab be unplugged, like the radio, abs, dash gauges, suspect relays that might have been in a stuck-on state, etc... have already been checked/isolated)...

That is when someone needs to get the wiring diagram out and start isolating key-on circuits (usually by cutting wires at key points on the system to see what direction the power is leading from, then soldering/heat-shrinking them back together) to find the source of the power that is remaining on when the keys-witch is off.


User's Signature: ->: What I post is just my own thoughts and Opinions! --- I AM Full Of S__T!.
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04-09-2022, (Subject: Truck not shutting OFF after running in rain.. ) 
Post: #9
RE: Truck not shutting OFF after running in rain..
some things to try, may or may not be helpful...

try disconnecting the batteries. leave disconnected for a few minutes before hooking them back up to ensure any on-board computers/circuit boards fully power down.
maybe a bad relay somewhere? Check all your fuses and relays.
maybe start checking wires for a short? start at the batteries and work your way around, don't forget checking the starter. Could have a (+) wire somewhere feeding power to another circuit?

idk, just some thoughts that come to mind


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