dreaded 'M' & 'S' light flashing!!!!

I was plagued with the odd auto M & S fault flash which cleared with a switch off and restart until just before Xmas when....
-Fuel pump failed at 40mph (engine stops with car in gear, coasted to the side of the road)
-Winched myself off the road as causing an obstruction (battery flat by the end of it [I must rewire it off the secondary circuit!!!])
-Towed to garage (10mph at the most but failed to put transfer box into neutral as lever jammed):doh:
-Fuel pump fixed but 'M'& 'S' lights come on and will not go out.
-Diagnostics say it's the XYZ Selector
-source a 'cheap' (£300!!!) genuine new part
-Fitted using diagnostics problem goes away
-Change to my 'offroad' wheels and tyres
-'M' & 'S' lights return!!!! driving in limp mode, diagnostics say XYZ again but I know that's new and OK.:doh:
-Freezing cold today and no lights and drives normally!!!

I'm thinking it's a poor earth (affected by jacking up to change the wheels), but where the fault 'cure' of today comes from I'm stumped!!!

grateful for any ideas as to where to look

new doesnt allways mean okay,low battery voltage can cause issues,what does fault code actually say

-'M' & 'S' lights return!!!! driving in limp mode, diagnostics say XYZ again but I know that's new and OK

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that switch is quite reliable, usually the problem is bad contact in the plug or chaffed wiring, see this http://www.landroverclubvi.com/uplo..._manual_mode_light_illuminated_860403nasf.pdf the plug u can check yourself and the harness needs continuity check from one plug to another ...off course if the battery is strong enough

AHA! sounds like a job for an auto electrician

gazjacko said:

AHA! sounds like a job for an auto electrician

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Before you spend any money at all, put your car battery on charge overnight or longer, then see if there is a problem.

The autobox ECU (like all of 'em) is sensitive to voltage drops, if your battery is weak and after starting the engine weaker still, the 'box ECU won't have enough volts to work properly.

Give the battery a really good charge.

Dave

starts on the slightest turn of the key so I'm wondering if the use of the winch without the engine running just dropped the voltage to trip the fault code.
The 'M' & 'S' lights haven't come back for a couple of days (touch wood) but this post has probably put the jinx on that!!!