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Mopar Certified, Dodge Technician
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Experience:  24 Year Chrysler/Dodge Certified Specialist
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how do i diagnose and repair code P1389 on 2002 dodge ram 1500

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how do i diagnose and repair code P1389 on 2002 dodge ram 1500 5.9L
Welcome to Just Answer Dodge my name isXXXXX don't know your automotive experience level, so I may have to ask questions of you before I can help.

Does the engine start and run?

Do you have a volt meter and want to diagnose this yourself?

Customer: replied 4 years ago.
truck does not start . i have voltmeter . i have automotive and electrical experience
Ok thanks.

So, this code indicates that the PCM is not getting supplied power from the asd relay.

This can be caused by a simple blown fuse, or potentially a bad relay.

The PCM gets this power on the dark green wire with an orange tracer in spot #12 on the C# XXXXX of the PCM. The C# XXXXX is grey in color.

The fuse in question is in spot #2 in the underhood fuse box and is a 30 amp fuse.

Start with the fuse and relay and check for voltage on this wire while cranking.

Let me know how it goes.....

Customer: replied 4 years ago.
the fuse and relay are ok . the # XXXXX spot on the C connector of the PCM does not have voltage while cranking engine
Ok, thanks. If you haven't tried a new relay, or swapped it with another, now is the time to try that.

Next, you would need to check the continuity of that wire from the PCM, back to the asd relay, pin 87. You should have less than 5 ohms resistance. If your meter shows it is open, then there is a break in the wire.

At the relay, also make sure pin 30 has constant battery voltage.

You can also bypass the relay by installing a jumper wire from #30 to 87 and this will send power to that wire in cavity 12. You can try that and see if it will start.

I'll let you try those things, and let me know what you find.

Customer: replied 4 years ago.
continuity of wire from PCM to pin 87 of ASD relay is ok (0.3 ohms). Pin 30 at relay has constant voltage. I jumped # XXXXX to # XXXXX and engine started. When a good relay (i checked it) is is installed the engine does not start. Could there be a problem inside the integrated power module ?
Yes, there could be an internal issue with the IPM.

Pin 85 also needs 12 volts since it comes from the same souce as pin 30, so check that as well.

If you have voltage on 85, then the remaining relay pin is the ground wire to trigger the relay and the PCM is responsible for triggering the relay.

The ground wire from the PCM is dark blue yellow in the C7 location 11.

Try manually grounding this wire and see if that will trigger the relay. If it does, then it sounds like a potential PCM issue.

Let me know....

Customer: replied 4 years ago.
pin 85 has 12 v. does dark blue yellow mean dark blue with yellow tracer ? Pin location 11 is yellow w/red tracer the dark blue w/yellow tracer is pin # XXXXX if this is the same pin plug as mentioned before with the # XXXXX spot on the C connector of the PCM
Ok good. Yes, that is correct.......yellow tracer.

Sorry, maybe I wasn't clear........the C7 at the bottom of the IPM.

At the PCM, it is pin location #3.

Hope that clarifies things for you.....

Mopar Certified and other Dodge Specialists are ready to help you
Customer: replied 4 years ago.
Thank You . Found a break in ground wire while checking for continuity .

Thanks for the good rating as well!

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