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Robert R
Robert R, ASE Certified Master
Category: Dodge
Satisfied Customers: 4096
Experience:  Dodge Master Certified, Dodge Sprinter Certified
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08 3500 6.7 no start or turn over comes up with no bus

Customer Question

08 3500 6.7 no start or turn over comes up with no bus
Submitted: 12 months ago.
Category: Dodge
Expert:  Robert R replied 12 months ago.

Hello, welcome and thanks for asking your question. My name is*****'m a Certified Auto Technician with 28+ years experience. I will do my best to assist you. please keep in mind that I may need to ask questions of you before I can answer. When you reply please feel free to add as much detailed information as possible pertaining to your concern.

The most common cause for no start with a "No Bus" displayed in the cluster is a failed ECM. Another possibility is a communication issue caused by a wiring issue or a failed module.

The best way to start diagnosing this is to have the vehicle scanned. Any codes retrieved will help. If you are not able to communicate with the ECM, that is a good sign of a bad ECM.

If you need a diagnostic procedure for no response from ECM let me know...

Keep me posted and let me know if you have any additional questions...

Thank you,

Robert

Customer: replied 12 months ago.
Is there any way to test the ecm . to give a little more information about the problem the horn does not work the headlight will not come on with the switch but will come on with the key in run position. The radio will not work nor will the overhead console.
Customer: replied 12 months ago.
I have used a snapon scanner and it will not connect with vehicle
Expert:  Robert R replied 12 months ago.

You would have to send the ECM out to a repair facility to have it tested.

From what you are describing, you are having a communication breakdown. The clue is that the headlamps only operate with the ignition turned on.

Try something, completely disconnect the radio and see if you can get it started. I have seen radio's cause a communication issue with no start...

In the mean time, I can gather some diagnostic procedures for you if you like...

Keep me posted...

Thank you,

Robert

Customer: replied 12 months ago.
I have removed the radio and nothing has changed I have unplug all of the modules that I can find and tryed to start or for change in the better.no luck. Yes please find some procedures that would be great before I spend $2300 on new ecm
Customer: replied 12 months ago.
Would it be possible for the (timp) to be the problem
Expert:  Robert R replied 12 months ago.

Yes, TIPM is definitely a possibility.... This is the gateway module and it can definitely be the root cause of a communication issue. Still working on the diagnostic procedures for you...

I'll be back asap.

Thank you,

Robert

Customer: replied 12 months ago.
K thanks
Expert:  Robert R replied 12 months ago.

Here is some info for you on no response from ECM. Remember that the best scanner to use is a factory scanner (WiTech Scanner).

No Response Flow Chart

Checking ECM Power and Grounds

ECM C1 Pinout

ECM C2 Pinout

Keep me posted and let me know if you have any additional questions...

Thank you,

Robert

If you need additional information, don't hesitate to ask. If I have answered your question, Please kindly"Rate" my service, it is greatly appreciated. Thank you and thanks for asking your question!

Robert

Customer: replied 12 months ago.
With the can bus - check the paper work that you sent me has the ecm harness #21 but if you count pin location it's 19 my harness is blank in that spot any ideas
Customer: replied 12 months ago.
That's in the c1 harness
Expert:  Robert R replied 12 months ago.

Can you rephrase your question? On the CAN Bus circuits, CAN + should be pin 1 and CAN - should be pin 21 of the C2 connector not the C1.

Keep me posted...

Thank you,

Robert

Customer: replied 12 months ago.
Might be a stupid question but why would I have gotten .5 omes from timp 1to 1 c1 connector for the can bus +
Expert:  Robert R replied 12 months ago.

Exactly which connector and pin number on the TIPM and which pin are you testing at the ECM for CAN +??

Customer: replied 12 months ago.
I had timp harness c6 pin 1 to ecm c1 pin1 and I got the .5 ohms. I understand that I had the wrong ecm harness now my papers must have gotten mixed up
Customer: replied 12 months ago.
I will try the weight harness tomorrow
Expert:  Robert R replied 12 months ago.

I think you were on the correct connector. The C2 ECM connector pin 1 is the CAN + ckt. Pin 19 is empty and pin 21 will be the CAN - ...

Keep me posted...

Thank you,

Robert

If you need additional information, don't hesitate to ask. If I have answered your question, Please kindly"Rate" my service, it is greatly appreciated. Thank you and thanks for asking your question!

Robert

Customer: replied 12 months ago.
Let make sure I am thanking wright about the ecm Connors c1 is the most forward one and c2 is toward the cab
Expert:  Robert R replied 12 months ago.

Actually, it should be the opposite. The C2 is the most forward connector and C1 is towards the cab...