Several weeks ago or about a month+ ago I posted a thread begging for help with a gearbox fault error that came up on my 2005 S-Type that I had for only about 2 months and the car was in limp mode for about 3-4 weeks...I had no idea what caused it but after a "trend" that I saw happening I had an idea what it was..Here we go...the first time I ever took it to a car wash later that night I received a gearbox fault light and it went away later on...car ran just fine....couple weeks later I take her to get a car wash...next morning I get a gearbox fault light...but this one stayed for weeks as I had no time to get her checked out or to read the codes until user 'norri' suggested I purchase an obdII reader which is what I did..once I received it I plugged it in and read the codes and nothing came up!!! I then cleared the codes (lol) and the gearbox fault error message/light went away ! I got excited as hell ! I put her in reverse pulled out the driveway...then I put her in drive and hit the gas and vrooooom she takes off...boy I was I the happiest person alive ! (keep in mind the car was in limp mode before I read/cleared the codes and wouldn't go past 10mph I believe). The gearbox fault error didn't come back on until guess what ? I took her to a car wash several weeks later and the following morning I see the fault light came back on...I then cleared it again and she ran just fine...but I wanted to pin point what was causing the fault light to keep coming back...I then remembered back that only after car washes it would come up...I then read quite a few post that other s-type owners had gearbox fault messages come up due to water getting through the windshield and would wet something electrical that caused a false gearbox fault message to come up...I inspected my windshield and seen that It had been replaced...I continued to inspect and noticed at the bottom of the windshield the rubber weatherstrip I believe what it's called had no silicon or whatever they use to seal it...I then had to do a test...I covered the strip with tape and took her to the car wash and didn't receive a fault until I took her to get washed the following week but this time I kinda forgot to cover it with tape and the following morning I get the gearbox fault message once again...cleared it again and car is running just fine...I purchased some clear windshield sealer and sealed it where it was missing silicon but I have not yet tested it at a car wash as its been really cold and windy so the car washes are closed..I will be testing it once it warms up a bit...so yea

I'll report back with results after I get to a car wash ! Thanks for reading =D

In the image attached is what I mean that the idiots who installed the windshield "forgot" to do...

 

I need to do that to mine as well. The cowling doesn't seal very well against the glass (esp with age).

 

So, a few possibilities:
1. it's letting water past - a disaster - so seal it (don't delay, just do it)
2. it's a coincidence and actually what's wrong is that the shifter cable is not held properly at the transmission side - should be 2 bolts but they may be loose/missing
3. your battery is starting to die - if in doubt replace it as it's the #1 cause by far of every weird error

Chances are codes are in the TCM but most tools only read PCM.

 

I'm still sticking with #1...I sealed it a couple days ago !...I strongly believe it was the water from the car washes getting through what caused the gearbox faults as I have tested it ! I replaced the battery with a new one when I first got the gearbox fault message which was only a couple months ago so it's fairly new.

 

You know what JagV8 I'm taking my words back ! I'm starting to think it's the shifter cable, I'll post tomorrow on what I'm currently experiencing with my gearbox issue...and see if I can get some help and get my baby repaired