Engine/Transmission (1998.5 - 2002) Torque Conveter Lock/Unlock & P1690 resolution

[SMcGrady]

Well, it seems that I stumbled on the right combination to correct the problems I was having with my truck. I wanted to post this in case it could help someone else who might be experiencing similar problems.



The first sign of trouble was when my truck would rapidly shift back and forth between 3rd and overdrive regardless of driving on the level, uphill or downhill.

I posted a question about this and got many suggestions, several of which I tried in turn.



The first thing I did was get the codes read. The only code I got was P1690.

I posted this finding and a few people told me my VP44 was probably failing.



After hearing that, I was pretty bummed out:{, but I started thinking of other possible causes. I just bought this truck and it only had 40k miles on it. The previous owner put a new fuel filter on in 2003 at 30k. This made me think that maybe I had a badly clogged fuel filter. (I know, I know... the gauges are going on next weekend. ) So I changed the fuel filter. Things got better briefly, then the same problem and code returned.



So... I did the following:

I cleaned and checked my battery terms and all the grounds I could find. Then I wrapped the alternator wire in aluminum. I ordered the Noise Filter from DTT and installed it a week later (and took off the aluminum).

I cleared the codes and started driving... viola! no codes, no more shifting problems. I did not know how the p1690 code related to the T/C unlocking problem, but so far, so good.



The only other thing that I've done is to replace the OEM LP with an AirDog FP100. I did this immediately after I checked my fuel pressure before and after the fuel filter and both readings were below 4 psi... Ouch!



Now all seems well. I have new gauges to install next weekend, but that should be no problem.

I hope my VP keeps working, I haven't gotten any codes for over a week now.



Thanks to everyone that helped me out! I am new to diesels and I really appreciate the folks here who are willing to share their knowledge and experiance!:-laf:-laf



Scott-

 

[ToolManTimTaylor]

The first sign of trouble was when my truck would rapidly shift back and forth between 3rd and overdrive regardless of driving on the level, uphill or downhill.



The only code I got was P1690.

I posted this finding and a few people told me my VP44 was probably failing.







Scott-

The 1690 is a companion code NOT a failing VP44. Usually the vp44 failure equates to a 216 code.



Line "Noise" has plagued many of the 2nd gen trucks and the filter or "Happi Box" or DTT noise filter does the trick.