Is the check engine light coming on, too? If so, get the codes read and see what that tells you.

Brian.

 

There are 14 different transmission-related faults that will trigger flashing M&S lights. Without getting the codes read with a diagnostic tool capable of reading transmission codes you are largely shooting in the dark. That said, as a previous poster asked, are your gear positions displaying correctly in both the instrument panel LCD and in the red LEDs in the shifter surround? If not that is an indicator of a failed or misadjusted XYZ switch. Beyond that, as others have said, voltage problems are the leading cause of the flashing M&S lights not actually caused by a problem with the transmission.

 

When I had code P0748, had both green S & M blinking, D light blinking on dash by speedo and locked in Drive (while driving)...but had check engine soon light on too.


It was a terminal in the black plug on the trans had slid out. Pushed it back in and all was well again.


Brian.

 

I believe the lights do correspond to PRND, but when I attempt to shift to 1,2, or 3 the lights stay flashing at D.
A new development in the case is that I finally was able to borrow a code scanner and came up with a P1562. Now Google can be your best friend or your worst enemy and in this case it came up with several different answers. One of which was that system voltage was below 9V, which I checked and was not the case (at the battery anyway). I think I would still like to check voltage at the components in question if I can find them.

 

Well, you may have correct voltage at the battery...but the TCU/M (Transmission Control Unit/Module) may not be seeing that voltage. Now, you have to verify correct voltage at the module. "I believe"...but am not sure...but I'm pretty sure the TCU/M is under the drivers seat.

Maybe, someone here has a wiring diagram.

Good luck,

Brian.

 

I just fixed my 2003 Disco with the 4.6 and automatic tranny. I replaced the battery and the alternator and that didn't work. I wanted to upgrade those two things anyway. This pushed me to buy an OBDII scanner which threw me the codes for a upstream o2 sensor and a crankshaft position sensor. I replaced all o2 sensors, the crank sensor and even the knock sensors since I was there and it fixed the problem! No more M&S lights! I am assuming the fix was the crankshaft position sensor.

 

Hi there...How much to change out upstream O2 and crank sensors?

 

These are easy things to do if you are mechanically inclined - just look up parts on Atlantic-British or elsewhere. But… make sure this is truly the root of the problem. Plenty of issues to chase for flashing M/S lights.