The ask an MOT tester thread

[meb90]

Quick one on mixing tyres:

My (company) car had the offside front tyre replaced today. Original tyres were all the same, and summer tyres. New tyre fitted was a cross climate 2, so an all season I believe. Is it legal/unsafe/MOT fail/me over thinking to have this mix?

[Jazoli]

It’s legal and won’t fail, you can have 4 different types of tyres (summer,winter, semi slick and a M&S) and it’ll still pass, they just need to be the same size and type (cross ply / radial) across the axle.

[BunkMoreland]

sixor8 said:

My apologies for not ploughing through to see if this has been asked before. Is the 'ESP not available' message an MoT issue? The ABS still works and there is no yellow exclamation warning unless you actually press the button to turn the ESP off.

I've addressed brakes, tracking and next the battery, but the message persists.

It'll be an RPM sensor. Which one can vary. And IIRC Mercedes recommend replacement in pairs across the axle (but you can probably get away with just the one)

In terms of the message

MOT Manual said:

(e) ESC MIL indicates a system malfunction ___ Major

Its a fail.

Source : https://www.gov.uk/guidance/mot-inspection-manual-...

[Little Pete]

BunkMoreland said:

sixor8 said:

My apologies for not ploughing through to see if this has been asked before. Is the 'ESP not available' message an MoT issue? The ABS still works and there is no yellow exclamation warning unless you actually press the button to turn the ESP off.

I've addressed brakes, tracking and next the battery, but the message persists.

It'll be an RPM sensor. Which one can vary. And IIRC Mercedes recommend replacement in pairs across the axle (but you can probably get away with just the one)

In terms of the message

MOT Manual said:

(e) ESC MIL indicates a system malfunction ___ Major

Its a fail.

Source : https://www.gov.uk/guidance/mot-inspection-manual-...

This is a good example of how the manual and guide we use can be vague and not very helpful.
Firstly, that is not a MIL, malfunction indicator lamp. It is a warning message on the dashboard, all be it a very specific one.
If you open the section of the manual quoted and read 7.1.6 about SRS systems, it says warning messages are not a failure in their own right.
Do we apply the same logic to the ESC system? The reason for failure in the manual, 7.12(e), relates to the lamp, not a warning message.
There will be testers that would fail it and testers that would pass and advise it.

[BunkMoreland]

Little Pete said:

This is a good example of how the manual and guide we use can be vague and not very helpful.
Firstly, that is not a MIL, malfunction indicator lamp. It is a warning message on the dashboard, all be it a very specific one.
If you open the section of the manual quoted and read 7.1.6 about SRS systems, it says warning messages are not a failure in their own right.
Do we apply the same logic to the ESC system? The reason for failure in the manual, 7.12(e), relates to the lamp, not a warning message.
There will be testers that would fail it and testers that would pass and advise it.

manual said:

You must check all vehicles fitted with electronic stability control other than Class 3 vehicles.

Electronic stability control is also referred to as ESC, ESP, VDC, and DSC, among many other names. Some systems may be able to be switched off by a switch, whilst others might only be able to be switched off using an electronic menu system.

The dashboard warning lamp for these systems might take various forms and you should only fail a vehicle if you’re certain that the warning lamp is indicating an ESC malfunction. You might need to check the owner’s handbook.

My opinion.

I AM certain that warning is indicating an ESC malfunction.

This car is Class 4 obviously, so has to be checked. If it was switched off by a switch or via the menu you'd need to turn it back on to ensure it worked as you are obliged to check it on Class4.

When you pressed the button or found the menu, you would find it couldn't be switched on. Therefore its not working

Plus if you read the owners handbook as directed, it will tell you its a malfunction.

There's "if in doubt pass and advise" and then there's the stuff that should be straightforward. I suspect that as soon as you drive the car forward you'd get other warnings on the dash such as ABS in any case

Forgetting the MOT. I'm more irritated the poster couldn't find a repairer that could diagnose it without throwing non relevant parts at it! Especially when its common knowledge Mercedes love a speed sensor!

[ro250]

meb90 said:

Quick one on mixing tyres:

My (company) car had the offside front tyre replaced today. Original tyres were all the same, and summer tyres. New tyre fitted was a cross climate 2, so an all season I believe. Is it legal/unsafe/MOT fail/me over thinking to have this mix?

And although a pass, it's poor form for them to not replace both fronts. My 4 Series under previous ownership had tyres of different ages when I got it (on the rear). I only realised recently this was the reason for strange behaviours on acceleration around slow corners and in the wet. Changed both rears now and it's normal.

[Athlon]

BunkMoreland said:

Little Pete said:

This is a good example of how the manual and guide we use can be vague and not very helpful.
Firstly, that is not a MIL, malfunction indicator lamp. It is a warning message on the dashboard, all be it a very specific one.
If you open the section of the manual quoted and read 7.1.6 about SRS systems, it says warning messages are not a failure in their own right.
Do we apply the same logic to the ESC system? The reason for failure in the manual, 7.12(e), relates to the lamp, not a warning message.
There will be testers that would fail it and testers that would pass and advise it.

manual said:

You must check all vehicles fitted with electronic stability control other than Class 3 vehicles.

Electronic stability control is also referred to as ESC, ESP, VDC, and DSC, among many other names. Some systems may be able to be switched off by a switch, whilst others might only be able to be switched off using an electronic menu system.

The dashboard warning lamp for these systems might take various forms and you should only fail a vehicle if you’re certain that the warning lamp is indicating an ESC malfunction. You might need to check the owner’s handbook.

My opinion.

I AM certain that warning is indicating an ESC malfunction.

This car is Class 4 obviously, so has to be checked. If it was switched off by a switch or via the menu you'd need to turn it back on to ensure it worked as you are obliged to check it on Class4.

When you pressed the button or found the menu, you would find it couldn't be switched on. Therefore its not working

Plus if you read the owners handbook as directed, it will tell you its a malfunction.

There's "if in doubt pass and advise" and then there's the stuff that should be straightforward. I suspect that as soon as you drive the car forward you'd get other warnings on the dash such as ABS in any case

Forgetting the MOT. I'm more irritated the poster couldn't find a repairer that could diagnose it without throwing non relevant parts at it! Especially when its common knowledge Mercedes love a speed sensor!

It is NOT a fail, the fail is specifically for a LAMP. If a lamp is illuminated indicating a fault it is a fail, a warning message can only be advised, this was covered in one of the Matters Of Testing blogs.

Almost nothing on the MOT scheme is straightforward and you have to dig deep to check if you are correct, even the inspectors can get it wrong. For instance, on a test check they did on me they asked why I took time to check to check the belts on a child seat, stated I was wasting time on non needed checks. After I showed them the teeny bit in the book about child seat belts are seen to be part of the car of the seat is attached by isofix......well one nil me

You can only fail items that are specifically listed in the guide, script is not, bulbs are.

[Little Pete]

Athlon said:

It is NOT a fail, the fail is specifically for a LAMP. If a lamp is illuminated indicating a fault it is a fail, a warning message can only be advised, this was covered in one of the Matters Of Testing blogs.

Almost nothing on the MOT scheme is straightforward and you have to dig deep to check if you are correct, even the inspectors can get it wrong. For instance, on a test check they did on me they asked why I took time to check to check the belts on a child seat, stated I was wasting time on non needed checks. After I showed them the teeny bit in the book about child seat belts are seen to be part of the car of the seat is attached by isofix......well one nil me

You can only fail items that are specifically listed in the guide, script is not, bulbs are.

Agree with all of this, especially the bit in bold. I would pass and advise it. I sometimes read comments on forums where people complain about fails and advisories differing from tester to tester, and although this shouldn’t be the case, it shows how interpretations of the manual can differ.
Nice one with child seat too

Edited by Little Pete on Thursday 16th May 21:23

[BunkMoreland]

Athlon said:

It is NOT a fail, the fail is specifically for a LAMP. If a lamp is illuminated indicating a fault it is a fail, a warning message can only be advised, this was covered in one of the Matters Of Testing blogs.

Problem there is that if a car has a digital display screen, and not an actual bulb/lamp then that rules out everything!


(not my pic)

Cause if we're excluding everything thats not a lamp. Then we cant fail an "icon" because its essentially a warning message. Then nothing is a fail on 95% of cars post about 2020!

[Athlon]

BunkMoreland said:

Problem there is that if a car has a digital display screen, and not an actual bulb/lamp then that rules out everything!


(not my pic)

Cause if we're excluding everything thats not a lamp. Then we cant fail an "icon" because its essentially a warning message. Then nothing is a fail on 95% of cars post about 2020!

Counts as a lamp as it is not text...

[Little Pete]

BunkMoreland said:

Problem there is that if a car has a digital display screen, and not an actual bulb/lamp then that rules out everything!


(not my pic)

Cause if we're excluding everything thats not a lamp. Then we cant fail an "icon" because it’s essentially a warning message. Then nothing is a fail on 95% of cars post about 2020!

I would fail that too, it is clearly an engine malfunction indicator. The digital display screen is just the latest version of the dash/clocks, as LEDs are to bulbs.

[BunkMoreland]

Athlon said:

Counts as a lamp as it is not text...

Show me THAT in the manual!

[Steviesam]

Peugeot Boxer van. The ABS and ASR (think that anti skid) lights DO NOT flash up when you turn the car on, so will fail the MOT.

Any clues? No warning on dash! I am stumped!!

Cheers

[sixor8]

Little Pete said:

Athlon said:

It is NOT a fail, the fail is specifically for a LAMP. If a lamp is illuminated indicating a fault it is a fail, a warning message can only be advised, this was covered in one of the Matters Of Testing blogs.

Almost nothing on the MOT scheme is straightforward and you have to dig deep to check if you are correct, even the inspectors can get it wrong. For instance, on a test check they did on me they asked why I took time to check to check the belts on a child seat, stated I was wasting time on non needed checks. After I showed them the teeny bit in the book about child seat belts are seen to be part of the car of the seat is attached by isofix......well one nil me

You can only fail items that are specifically listed in the guide, script is not, bulbs are.

Agree with all of this, especially the bit in bold. I would pass and advise it. I sometimes read comments on forums where people complain about fails and advisories differing from tester to tester, and although this shouldn’t be the case, it shows how interpretations of the manual can differ.
Nice one with child seat too

Edited by Little Pete on Thursday 16th May 21:23

Perhaps I should have kept going and crossed my fingers for the MoT in September with the ESP unavailable warning. I could still turn the ES off to get a yellow light on, pressing it the lamp would go out but the message remain. I put the SLK into a specialist for diagnosis. My shortlist was the ESP module, wheel speed sensors, brake pressure switch or the steering angle sensor. It was the last on that list.

I can do most fixes on my cars myself but for several reasons (recent family bereavement is one) plus removing the steering wheel could cause me headaches, I'm letting them do it. Quote is £600 (£100 of that is diagnosis!) to fix but then it came up that the 'clock spring' part was also u/s after changing the outer sensor. Then it was the steering angle sensor was faulty again, a brand new one from Mercedes (I'd read elsewhere there are faulty batches). Mercedes themselves now have the car to replace the steering angle sensor under warranty. I've been without the car for 12 days now, fortunately I've others.

[RSTurboPaul]

Steviesam said:

Peugeot Boxer van. The ABS and ASR (think that anti skid) lights DO NOT flash up when you turn the car on, so will fail the MOT.

Any clues? No warning on dash! I am stumped!!

Cheers

I thought it was the case that a 'test' warning lamp had to extinguish after the vehicle is started - so therefore if there was no lamp initially lit, there was no fail possible?

I await being told I am wrong lol

[driveaway]

mintybiscuit said:

What is the accepted minimum ' drink' you will accept to pass a dodgy car ?

[driveaway]

So on one of my volvo's, the engine light is coming up, for which apparently it is nothing serious at all (that's what the mechanic said), but is a tedious job as it means playing around with the crankshaft.
What do you say...?

[mk2 24v]

driveaway said:

So on one of my volvo's, the engine light is coming up, for which apparently it is nothing serious at all (that's what the mechanic said), but is a tedious job as it means playing around with the crankshaft.
What do you say...?

What age is said Volvo, and is it petrol or diesel?

[driveaway]

mk2 24v said:

What age is said Volvo, and is it petrol or diesel?

Petrol 06 plate c70

[mk2 24v]

driveaway said:

Petrol 06 plate c70

EML on will be a fail (and its a fail if the EML doesn't come on and do its thing as well)