MiL Light - Can This Be Unplugged From The Back?

[im]

My light keeps coming on and having taken the car to Austec I'm told the fault code is spurious (Stepper Motor Error) as it is throwing this up even if a replacement stepper motor is installed.

Apparently its more than likely a simple MA mapping quirk thats throwing this error code up and thus lighting the MiL light. Anybody who says "why not contact MA?" clearly hasn't tried to do this themselves in the last 6 months

Anyway, long question short, can I simply unscrew one side of the dash-top, gently lift up a couple of inches (without having to undo the 2 screws on the passenger side) reach in and unplug the light?

Many thanks for your anticipated wisdom.

Ian

[Ribol]

You won't get to the back of the MIL light without taking the dash top off.

Very easy to do, only 3 x 10mm nuts holding it on.

[pilgrim13]

I think the light is built into a circuit board, my ice light was staying on and I had a look at the back of it and its built into the circuit board, I'm sure the one your talking about is the same. Used black tape over the front in the end!!!!

[Chimjunkie]

Could it not be disconnected from the ECU connector block?

[im]

That would be so much easier - any ida how you'd do that?

[blitzracing]

Id take a step backwards on this. I dont believe Mark Adams chips give such errors, theres a reason for the ECU light. The error will come on if the tickover cannot be maintained at the correct rpm, within the stepper motors correct maximum and minimum travel range. This could be the base idle is too high or low, or there is a slight air leak somewhere in the plenum / inlet manifold. You need to get the engine warm, then block or clamp the air feed pipe to the stepper motor. The base idle screw (hex head screw recessed into the plenum, by the throttle body) then needs winding up or down to get the engine to tick over at around 600 rpm. Once you remove the pipe, the tickover should rise to the RPM set in the ECU chip. On the stock TVR chip its 800 rpm, but I think the MA chip is a bit higher. Accordingly you might need to experment a bit with the base idle a bit to bring the stepper in range. One thing about the Adams chip is it enables the MIL light to come on when something is wrong, unlke a lot of stock chips.

mark

Edited by blitzracing on Sunday 14th September 10:04

[im]

Hmmm...interesting.......

I can only go by what I've been told by 2 techies at Austec as to the prime reason for the light coming on all the time.

However, what you say does make sense as well and the idle can be slightly erretic but not as dramatically so as was the case before I had the air flow restrictor inserted into the air hose to the stepper motor.

Bottom line though is that I'm not going to pay £400-£600+ to get the car re-mapped yet again. It's been done twice in the last 18 months and as the car 'seems' to be performing well I don't really want to 'upset' it - I just want the bloody light to go out

[blitzracing]

It seems a pitty to disable a useful function just for this, and unless the programming is very bad, that I doubt for even a moment, this is mechanical fault / mis adjustment or air leak. Block the air pipe to the stepper, and see what the tickover is. If its above about 800-900 rpm, this is likely your fault, as the stepper is trying to slow it down, and can't shut the air supply off enough to get it in range.( this is where the MA chip may be different if hes raised the tickover) Winding the base idle up is used when the cars tend to die when idling, but really is only needed if something else is wrong and a poor work around. Otherwise you could cut the MIL wire where it enters the ECU socket. The signal is grounded when the MIL come on, so you wont do any damage. I think its Black/Yellow, on pin 10, but this is from a Range Rover manual, so Id get a second opinion.

Mark

[blitzracing]

Just re read your post..Restrictor um, likely to be the other way then, stepper trying to hold the rpm higher when cold, and cant due to the restrictor not letting enough air in. I guess you had a wildly fluctuating tickover then, and tried to fix it this way. There are multiple reasons for the origional fault, but if it works as it, then I can see a pair of snippers looming......

Mark

[im]

blitzracing said:

Just re read your post..Restrictor um, likely to be the other way then, stepper trying to hold the rpm higher when cold, and cant due to the restrictor not letting enough air in. I guess you had a wildly fluctuating tickover then, and tried to fix it this way. There are multiple reasons for the origional fault, but if it works as it, then I can see a pair of snippers looming......

Mark

You're spot on Mark. I did have a VERY wildly fluctuating idle - sometimes up as high as 1800-2000 which, when stopped at traffic lights, is red-face time

This problem couldn't be solved by either MA or TVR Power hence SC Power developing their restrictors.

It works a treat but can need a bit of messing about to get the correct size hole for the revs you're trying to achieve - and over time this too can alter. I've gone from a 5mm to 8mm hole in the last 15 months.

At this rate of expansion (of hole) perhaps soon I wont need a restrictor at all!

Anyway - yes, I too can see the snippers coming appearing from out of my sideboard as we speak...