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Ask Juan Crespo Your Own Question
Juan Crespo
Juan Crespo, ASE Certified Technician
Category: Dodge
Satisfied Customers: 1513
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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99 durango. Check engine light on. No communication with

Customer Question

99 durango. Check engine light on. No communication with pcm. Still runs. Replace pcm, still no communication. I have the 2.5 volts at dlc and pcm connectors.
Submitted: 9 months ago.
Category: Dodge
Expert:  Juan Crespo replied 9 months ago.

OK. That's the correct voltage at both ends of that bus, which will normally indicate a bad PCM. Does everything else work as it should, i.e., instrument panel/gauges, trans shifts OK, ABS work OK, etc.? Is the scan tool OK?

Customer: replied 9 months ago.
What happened is the trans stopped shifting. Check engine light came on. Tried to read codes but no communication. I can talk to the body, abs, and airbag controllers. I can talk to the pcm in global obd. But it says manufacturer specific code. I am using a snapon modis. I have another dodge sitting right next to this one and my modis works fine on that one. Tried a new pcm. Still no communication, and doesn't run with new pcm. Does run with old pcm
Expert:  Juan Crespo replied 9 months ago.

The trans control module is in fact part of the PCM. If that other Durango is identical in every aspect regarding powertrain and accessories, the reason why your vehicle doesn't run with that other PCM might be because it has not been configured to your Durango's VIN.

The whole thing can be related to the trans not shifting. First thing you need to do is turn the ignition off and climb under that truck and disconnect the harness plug to the solenoid pack in the trans. Clean it thoroughly and inspect both halves for bent pins, corrosion, or any other thing that could cause an open circuit. After the inspection, spray both halves liberally with WD-40. Next, plug your scanner back in and turn the ignition on. Please tell me if that takes care of the issue.

Best Regards.

Customer: replied 9 months ago.
Hi, I will look at the solenoid pack connector. I'm sure the problem is in the trans. But can't communicate to tcm or pcm. The communication part I believe is a separate issue than the check engine light no shift. I purchased a new pcm for this durango and Vin and mileage ect was programmed to it. I'm looking into a possible bad connection at the dlc. I will let you know
Expert:  Juan Crespo replied 9 months ago.

Got you. Please let me know what you find.