06 no communication issue kicking my a$$

cityredneck

cityredneck

Diesel Mechanic
Joined
Sep 27, 2009
Messages
393
So I have an 06 5.9 auto here. Customer had installed and engine himself and brought it to me with a long story. It wouldn't fire. Everything leading to an ecm I swapped a known good one in. It fired and would shut off due to security. So he gets a used ecm out of a running truck and brings it. It will start and shut down just like the last but when I go to flash the truck with efi it will not communicate with the ecm. Same with my solus ultra. So I Clean all battery connections, clean and check all grounds. Check my power and grounds the the ecm connectors, check power and ground at my obd2 port. I ohm'ed circuits from the c1 connector to the TIPM for can+ and can -. and from tipm to obd for can + and can -. I have also tried 2 good tipm's just to be sure and same thing.

Now my diagram is showing at the data link connector there are some ecm transmit and receive wires as well but the diagram shows those going to the (pcm) (what pcm)??

Im pretty stumped here. So basically truck will fire but no communication with ecm to flash or read data. Im wasting to much time on this one and starting to go nuts..:bang
 
yes. after clearing codes and doing a full code scan I am getting
u0100 lost comm with ecm/pcm
u0121 lost comm with abs module
u0169 lost comm with sunroof control module
u0195 lost comm with sdars
u0197 lost comm with hands free module
u0186 lost comm with audio amp

u0141 lost comm with tipm
b2204 ecu configuration mismatch

. Many would make sense with not communicating. But truck will still start?
I am not sure if I am getting the full story on this from the customer either. I am going to call him in the morning. I found another engine harness in the cab. Does the can circuit on these need to be shielded?
 
cityredneck said:
yes. after clearing codes and doing a full code scan I am getting
u0100 lost comm with ecm/pcm
u0121 lost comm with abs module
u0169 lost comm with sunroof control module
u0195 lost comm with sdars
u0197 lost comm with hands free module
u0186 lost comm with audio amp

u0141 lost comm with tipm
b2204 ecu configuration mismatch

. Many would make sense with not communicating. But truck will still start?
I am not sure if I am getting the full story on this from the customer either. I am going to call him in the morning. I found another engine harness in the cab. Does the can circuit on these need to be shielded?
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That's not good, the same thing you describe happened with my 6.7 I was jumping the starter on. Got it to fire and run for 3 sec then it would die. Eventually it quit starting and I was receiving those codes you're getting
 
What was your issue in the end? Im leaning towards bad ground or can circuit. Although I can wrap my head around how to repair it when it seems to be checking ok.
 
cityredneck said:
What was your issue in the end? Im leaning towards bad ground or can circuit. Although I can wrap my head around how to repair it when it seems to be checking ok.
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I can't say honestly... however after I sold the ecm and decided I was going to use the cmb849 ecm I pulled the head off to find a couple piston bowls filled with diesel.

It could of been a few reasons why my engine wouldn't run anymore.

Maybe try another ecm, or bench flash an updated file in the current ecm.
 
Im on the 3rd ecm. I am going to find out tomorrow what the deal is with the other harness in the truck and see about building a bench harness. I need one anyway

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Thats pretty trick. Im curious what the male connector on that harness is for? I have an obd2 port coming on friday. From my understanding its only about 5 wires needed to bench flash

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cityredneck said:
Thats pretty trick. Im curious what the male connector on that harness is for? I have an obd2 port coming on friday. From my understanding its only about 5 wires needed to bench flash

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It's for the switch/power/obd2. There's a couple options available the hobbyist series or the professional.


yes 5 wire to the obd2. Power, 2 grounds, can+, can-
 
DieselheaD said:
It's for the switch/power/obd2. There's a couple options available the hobbyist series or the professional.


yes 5 wire to the obd2. Power, 2 grounds, can+, can-
Click to expand...
Do you know which power needs to be hot. Im not at the shop now but there are a few constant and 1 key on

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Opps you said to the obd. I meant to bench the ecm. Sorry

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cityredneck said:
Do you know which power needs to be hot. Im not at the shop now but there are a few constant and 1 key on

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Click to expand...


50 pin plug

#50 ground
#40 hot
#32 is your key on

60 pin plug

#4 can+
#5 can-
 
Last edited:
Do you know if the can's need to be shielded?

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Shielded wires are the type that are twisted with a foil strand as well to keep out other voltage. But i guess if yours wasnt that answers the question. And pics of your bench harness? Or did u buy the one from efi connection

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cityredneck said:
Shielded wires are the type that are twisted with a foil strand as well to keep out other voltage. But i guess if yours wasnt that answers the question. And pics of your bench harness? Or did u buy the one from efi connection

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Ah I gotcha, I used my modified 5.9 harness. Looks like a rats nest but it worked.



image_zpsy688qnku.jpg
 
Are the small ground wires going to the block clean? I've had freshly painted blocks have ground issues causing weird problems.
 
YoungDiesel27 said:
Are the small ground wires going to the block clean? I've had freshly painted blocks have ground issues causing weird problems.
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Yes. I even jumpered these straight to battery ground and tried as well

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