Thread: M and S lights – replaced xyz switch and problem is back – other possible causes?

Hey Gavin,
Alternator, m& s lights will come on then after , limp mode, then auto stAays i'n 3rd and then car shuts down this is what happened to me , after new alt I had to re set computer and all was good.One senario anyway
Hope it's all good shortly

G'Day Gavin. Start simple and work up to th more complex possibilities.
I've just spent 2 1/2 weeks pulling have my car apart looking for my M&S cause!
Earth points, XYZ switch, gearbox loom, oil in ECU loom etc etc.
Didn't start with the basics. The last thing I checked was the energiser wire to the Starter solenoid (the thin green wire). Loose oily connection. Pinch up with the pliers and Vroooooom!
Check the obvious simple stuff first.
A dying battery is a common cause, but you have discounted that and the XYZ.
Earths, Starter cables, connectors and a scan for faults.
Good luck.
Dave.

I had the same issue last week,. the car had been at the Airport long term, had it jump started and was ok for a couple of days, then on a REALLY cold morning it came up.
I plugged in my tester and it showed low voltage errors.
I replaced the battery and no more issues.

Yes, I too had the M&S last week. The dealer fitted battery of 560CCA was the cause...as i'm now running a Yellow top optima that has a tested 1050CCA...and no more problems. Is your battery big enough?

Ditto battery. I'm using a battery a fair bit smaller on one of our cars now since I changed it 2 years ago, but it's not caused any problems though.

BIG O
03 D2 TD5 AUTO
99 D2 TD5 AUTO ACE
94 D1 TDI 3 DOOR (GONE)

Hi. Another reason for M+S limp home is low fluid level in the auto. There is a really steep hill near my place - as I accelerated up the hill suddenly no power and on come the M+S lights. On restarting they went away. Next time it happened again so i checked the fluid level and it was low. I changed the auto filter and refilled and no more lights.
Martin

Hi all,
I too have the M&S lights coming on consistently when I select reverse gear after a cold start. Several other observations are that the red light on the selector and the gear indicator on the dash fail to light up in R and N until it's been driven for a bit. I've checked the batter voltage (12.25V off and 13.6 once running), but could a voltage drop from cranking cause the issue?

I'm keen to hear whether this is less likely to be the xyz switch given that it's most common just after startup. Note that letting the car idle for even a considerable length of time has no effect... will still start flashing when you eventually hit reverse and it's not always on startup - just more common at that time.

I suppose even ruling out battery by throwing in another one doesn't rule out earth issues etc.

thanks in advance...

I have often experienced this problem after selecting reverse on cold starts. The lgreen M&S dash warning lights do not start flashing while I am in Reverse, but do so as soon as I shift from Reverse into Drive. They disappear only after I turn the ignition off and restart the engine.

I have found recently that the M & S lights do not come on if I shift the selector from Reverse into Neutral, and then from Neutral into Drive, in two slow and separate movements. Try it -- it might work for you, too.

Eddie Vaughan