"M" and "S" light illuminated while driving (trans electrical fault), what to do?

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Hubjeep

Well-known member
Nov 30, 2006
96
0
Long Island, NY
"M" and "S" light illuminated while driving (trans electrical fault), what to do?

Howdy all,
the Manual mode "M", and Sport mode "S" lights are both illuminated on the 2003 Disco (126,000 miles). What do you suggest I do, I suppose my OBD II tool will be unable to diag this, does a LR dealer have to check it out?

Anyone have them come on?

Thanks,
John
 
martinquebec

martinquebec

Well-known member
Jun 19, 2006
155
0
montreal, Canada
Re: "M" and "S" light illuminated while driving (trans electrical fault), what to do?

Yo john...m+s flashing means that something is very bad that start...mine did it when my crank sensor began to fail...no crank no engine...so take the code (obd2) as soon as you can. Cheers
 
ptschram

ptschram

Well-known member
Sep 27, 2004
21,955
49
In the shop doing the Lord's work one broken Rover
www.ptschram.com
Re: "M" and "S" light illuminated while driving (trans electrical fault), what to do?

Relax. Deep breath. Repeat until blood pressure falls.

It could be as simple as a dying battery. First step, check battery.

Second step, call dealer and check if there are any outstanding recalls-particularly for the harness for the transmission. Third, search this site, I posted some info back when I was working for a dealer and encountered numerous problems like these.

PT
 
B

bigred

Well-known member
Apr 20, 2004
3,457
1
East Coast
www.hillbillytrailcrew.com
Re: "M" and "S" light illuminated while driving (trans electrical fault), what to do?

Low voltage at start up can cause that too. Check your battery, alternator, and grounds before you get too worried.

edit - Damn PT beat me.
 
H

Hubjeep

Well-known member
Nov 30, 2006
96
0
Long Island, NY
Re: "M" and "S" light illuminated while driving (trans electrical fault), what to do?

ptschram said:
Relax. Deep breath. Repeat until blood pressure falls.

It could be as simple as a dying battery. First step, check battery.

PT
Click to expand...

I was going to change the battery this week, Disco has been cranking over slowly. :cool: Will see if that helps. Thanks!

martinquebec - Does OBD II trigger those lights, or some special LR electronics?
 
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Ron

Well-known member
Jun 15, 2004
1,820
0
Main Line
Re: "M" and "S" light illuminated while driving (trans electrical fault), what to do?

Dead battery.

No biggy.
 
BuyRovers

BuyRovers

Well-known member
Jan 21, 2006
916
0
www.aluclassics.com
Re: "M" and "S" light illuminated while driving (trans electrical fault), what to do?

X2... Either a dead battery and/or alternator going out. Typically caused from low voltage.

C-
 
H

Hubjeep

Well-known member
Nov 30, 2006
96
0
Long Island, NY
Re: "M" and "S" light illuminated while driving (trans electrical fault), what to do?

THANKS everybody!!!!

Put a new battery in, it now cranks over amazingly fast and no more lights!

BTW, I hooked up my OTC battery tester, old battery failed, only indicating 150 CCA. :eek:
 
S

Swift

Well-known member
Sep 27, 2004
101
0
Re: "M" and "S" light illuminated while driving (trans electrical fault), what to do?

I'm glad the battery swap worked!
The other cause of the M&S lights is water getting in the auto transmission sensor that lives on top of the transmission. I've had it happen twice (the last time being 2 weeks ago). The first time water completely killed the sensor and it had to be replaced, but the most recent time it was just waterlogged and after turning the car off and letting the sensor dry out the lights (and the problem of being stuck in one gear) went away and hasn't returned.
 
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