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sprinkles08, ASE Certified Technician
Category: Transmissions
Satisfied Customers: 23123
Experience:  Chrysler/Dodge/Jeep master tech ASE Master and Advanced Certified, Chrysler/Dodge/Jeep Master Certified, Trans Specialist
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I have a 99 dodge pick up with the 5.9 Cummins. Driving down

Customer Question

I have a 99 dodge pick up with the 5.9 Cummins. Driving down the road my transmission come out of overdrive and my alternator quit charging. Any ideas on what is going on with it Iv replaced alternator ignition switch, and the computer nothing has fix it and checked all my grounds. I need some help a lot of $$$ and still no fix!
Submitted: 1 year ago.
Category: Transmissions
Customer: replied 1 year ago.
I have no power to my transmission relay if I put power to it the transmission works perfect but still no charge on my alternator my alternator will barely work you can watch the dome lights get bright for a second then shut off but the voltage on my – continues to drop as time goes on
Expert:  sprinkles08 replied 1 year ago.

Hello and welcome to JustAnswer!

If the trans stopped shifting and alternator stopped charing at the same time then most likely the powertrain control module is not wakae. The PCM controls charging, transmission, a/c, and cruise control functions. If the PCM is down then it has either lost a power or ground, has failed internally, or there could be a short to power or ground on a couple different circuits.

Does the a/c compressor engage?

Does the fuel gauge work?

Customer: replied 1 year ago.
the ac compressor works and the fuel gauge works and cruise works I dint get a new pcm but did biy a used one and nothing changed
Expert:  sprinkles08 replied 1 year ago.

Do you know what fault codes are setting in the PCM?

Customer: replied 1 year ago.
No cods show up on the scanner
Expert:  sprinkles08 replied 1 year ago.

The trans couldn't be in limp in or the alternator not charging, and the PCM be awake, but not have stored fault codes. The reason the trans goes into limp in is because fault codes set.

What did you use to check for codes?

Customer: replied 1 year ago.
I can Put 12v to transmission relay and the tranny works grat still no alternator
Customer: replied 1 year ago.
Transmission relay under the hood on the driver side back
Customer: replied 1 year ago.
Genesis OBD 2 tester. I got a p 1698 code
Expert:  sprinkles08 replied 1 year ago.

Was that stored in the ECM or PCM? That code sets when there is a code set in the companion module, whichever module this was set in you also need to read codes from the opposite module.

Customer: replied 1 year ago.
Codes were in the pcm
Customer: replied 1 year ago.
How do I read the codes in ecm?
Expert:  sprinkles08 replied 1 year ago.

If you don't know how to check for codes in each module I'm doubting that the P1698 was set in the PCM. I'm sure it's set in the ECM and there are codes related to the limp in and charging issue in the PCM. You need to pick ECM or PCM specifically from a module menu on the code reader. If it doesn't have the option you're only reading from the ECM.