Thread: M&S lights/Brisbane Landy mechanic

First thing to do (and cheapest) is to get your battery checked out. If it's weak, this is the first sign usually.

Originally Posted by janrob

Hi Gurus,

....... My 2005 D2 Auto has develped a problem with the M&S lights continually flashing if I reverse and then put into drive into drive, if I turn everything off, lock and unlock everything is fine. It is becoming more frequent.

Thanks in advance for any information.

Battery dying or more likely, failing XYZ switch.

mrautomotive - Home

MR Automotive will be able to scan it for you and make sure.
I have the same problem, cures on restart, but comes right back the next time. Waiting for tax return for the fix as its not to cheap!

I just took the xyz siwtch off and apart, cleaned and sealed back up - no more problems. Several people have had success with this so there's not necessarily any need to buy a new swicth just yet. Make sure your air con drains are diverted past the switch as well.

There are 18 listed reasons in the workshop manual why the M&S lights come. Sure, the gear position switch (also called the w,x,y,z switch in RAVE) is first on the list, but there are other reasons. A low battery may also cause them to illuminate, but I would have thought that if it was that low, it won't turn over the engine. (???)

The gear position switch is a leading cause, but not the only one and without diagnosis or inspection, prior to replacement, may or may not fix the fault. $300 (replacement cost) or a couple of hours taking it off, pulling apart etc on a maybe?? For example, when I first had the car, I moved the gear selector too quickly and got the lights, looked up the forum - "replace x,y,z switch" was on most threads. I used an OBD from Jaycar to fix my fault code. Can't recall if it reads the fault code, but it clears the fault.


From RAVE
The existence of an intermediate state (on the W,X,Y,Z switch)causes a fault code to be detected by the BCU. To reduce the chances of the fault condition occurring while changing selector lever position, the inputs are debounced and only considered valid when they have existed for at least 33 ms.


Also, from RAVE

While the ignition is on, the electronic automatic transmission (EAT) ECU diagnoses the system for faults. The extent of the diagnostic capability at any particular time depends on the prevailing operating conditions, e.g. it is not possible to check torque converter lock-up while the vehicle is stationary, or to check for a short circuit to earth if the circuit concerned is already at a low potential. If a fault is detected, the EAT ECU immediately stores a fault code and the values of three operating parameters associated with the fault. Depending on the fault, there are four possible effects:

• The fault has little effect on gearbox operation or vehicle emissions. The driver will probably not notice any change and the warning lamps remain extinguished.
• The fault has little effect on gearbox operation but may effect vehicle emissions. On North American specification (NAS) vehicles, if the fault is detected on a second consecutive drive cycle, the MIL illuminates.
• All gears are available but kickdown does not function. The sport and manual warning lamps flash. The MIL remains extinguished.
• Limp home mode is selected and vehicle performance is greatly reduced. The sport and manual warning lamps flash. In all markets, if the fault is detected on a second consecutive drive cycle, the MIL illuminates.

After the detection of a fault, the effects remain active for the remainder of the drive cycle. In subsequent drive cycles, as soon as the EAT ECU diagnoses the fault is no longer present, it resumes normal control of the gearbox. The conditions required to diagnose that the fault is no longer present depend on the fault. Some faults require the engine to be started, others require only that the ignition is switched on. After a fault has not recurred for forty warm-up cycles, the fault is deleted from the EAT ECU memory. Only five different faults can be stored in the memory at any one time. If a further fault occurs, the fault with the lowest priority will be replaced by the new fault.

Mechanical limp home
In the mechanical limp home mode, gear engagement is controlled by the manual valve. The gearbox is fixed in 4th gear if the fault occurs while the vehicle is moving, or 3rd gear if the fault occurs while the vehicle is stationary. 3rd gear is also engaged if a vehicle is brought to a stop and the selector lever is moved out of, and back into, D. Neutral and reverse gear are also available.

CAN data bus failure
In the event of a CAN data bus failure any of the following symptoms may be observed:

• EAT defaults to reverse and 4th gear if the vehicle is moving, 3rd gear if the vehicle is stationary.
• Harsh gearshifts.
• Sport and manual warning lamps flash alternately.

11v is low enough to trigger m&s but still enough to start. I have this happen occasionally when I've not done a reasonable drive for a few weeks.

Originally Posted by Marmoset

I just took the xyz siwtch off and apart, cleaned and sealed back up - no more problems. Several people have had success with this so there's not necessarily any need to buy a new swicth just yet. Make sure your air con drains are diverted past the switch as well.

How did you open and close? That switch is held with rivets.