I know this subject has been covered before. But I have a quick question. My buddy has his 99 Dodge that has the infamous lockup issue. I told him over and over it was the alternator. I told him to test by unplugging the alternator and of course the issue cleared up. I said he needed to get a Nations Alternator but he bought an O'reilly's reman alternator. After about a week he has having the same issue. But now even with the alternator unplugged the trans is still surging in and out of lockup. Could the PCM be failing now?

First, did he check the first alternator for AC noise?

Next, did he check the second alternator for AC noise?

Has he done the W-T ground modification?

Is there a 'Mystery switch ' installed ?

 

Before the PCM is condemned the following should be checked:

   Fuse #1 

   Transmission control relay (in the PDC)

   Torque convertor clutch solenoid 

   Wires and connectors from the PDC to the transmission

   Wires and connectors from the transmission to the PCM

Yes what he said check it. Mystery switch AKA torque converter lockup switch? (If it is the TC lockup switch it should be tapped into an orange wire on the big harness at the top of the firewall and if i remember right you have to have a jumper wire in place of the relay in the PDC) I tried that it was cool for a while and then my TC seized up and roasted the rest of the transmission trying to get it home... Lesson learned

 

On 9/12/2018 at 10:57 AM, IBMobile said:

First, did he check the first alternator for AC noise?

Next, did he check the second alternator for AC noise?

Has he done the W-T ground modification?

Is there a 'Mystery switch ' installed ?

 

Before the PCM is condemned the following should be checked:

   Fuse #1 

   Transmission control relay (in the PDC)

   Torque convertor clutch solenoid 

   Wires and connectors from the PDC to the transmission

   Wires and connectors from the transmission to the PCM

 

For what its worth heres my short story on this issue.

About a year ago I was dealing with the dreaded TC lockup which was more annoying than anything especially with a billet triple disc. Bought BD's noise isolator. Was fine until about 3 weeks ago got a P1689 code. After alot of looking around swapped APPS with a known good one. Checked VP plug. Checked ECM plug. Felt all the wiring for rat damage. Put back together and a week later same issue. Did W-T's wiring mod and unplugged the noise isolator at the same time and (knock on wood its only been a since Sunday) but i havent had an issue yet. It runs noticeably smoother. Shifts smoother. Throttle is smoother. Have yet to have it act up (again knock on wood)

Edited September 13, 20187 yr by 2000Ram2500
added