How to find out if a used car has been remapped
How to find out if a used car has been remapped
Author
Discussion

RossiAJ

Original Poster:

8 posts

86 months

Wednesday 1st March 2023
quotequote all
I have a BMW m140i and have been wondering whether it has been remapped by the previous owner.

My question is, is there a way to find out other than having to use a dyno to calculate the current bhp & torque?

Thanks in advance

s94wht

2,217 posts

89 months

Wednesday 1st March 2023
quotequote all
Take it to a tuner and they should be able to read the ECU

Watchthis

609 posts

92 months

Wednesday 1st March 2023
quotequote all
Time a few 0-60s and if they're significantly quicker than what they should be then you have a good indicator. Although BMW figures can be conservative

Terminator X

20,814 posts

234 months

Wednesday 1st March 2023
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If the driving position is set at "gangster lean" then there is a high chance of a map.

TX.

Rooted

39 posts

157 months

Wednesday 1st March 2023
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Use a £5 Bluetooth dongle and the Torque app to see what the peak boost figure the car pushes out. Compare this with what the stock peak boost level should be.

brillomaster

1,885 posts

200 months

Wednesday 1st March 2023
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Drive a few, the remapped ones will be obvious - boost will kick in earlier and stronger, and wont tail off as much as it approaches redline.

I remapped a 335i and the difference really was night and day. Drove so much better after the remap.

Glenn63

3,958 posts

114 months

Wednesday 1st March 2023
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If you have an m140 look up the performance dials on the screen if they read over 400bhp itl be mapped.
I thought mine had been mapped when I got it as it felt fast had it stuck on a dyno and it made 350bhp, they do seem to produce more bhp than claimed.

Chromegrill

1,140 posts

116 months

Wednesday 1st March 2023
quotequote all
God to know the types of car likely to have been quietly remapped to avoid them. Presumably if you buy a car that's been remapped without you being aware of it and you subsequently have a prang, your insurer will invalidate your insurance on the grounds that you really should have known better?

Baldchap

9,629 posts

122 months

Wednesday 1st March 2023
quotequote all
Chromegrill said:
God to know the types of car likely to have been quietly remapped to avoid them. Presumably if you buy a car that's been remapped without you being aware of it and you subsequently have a prang, your insurer will invalidate your insurance on the grounds that you really should have known better?
Legally it's all 'to the best of your knowledge', however how that all plays out when it comes to a claim is anyone's guess...

CG2020UK

3,005 posts

70 months

Thursday 2nd March 2023
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A remapped M140i is extremely quick I think you’d definitely notice.

Once tuned they are like 430bhp so they are proper missiles.

donkmeister

13,017 posts

130 months

Thursday 2nd March 2023
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Watchthis said:
Although BMW figures can be conservative
If you read enough posts on Pistonheads then you learn that every manufacturer ever is conservative with their 0-60 times, to the point that you wonder why we even bother having it on the specs.

Germans are well known for their devil-may-care attitude to quantifiable numbers, after all biglaugh

Acceleration runs aren't a particularly good way of ascertaining the absolute power of a car - too many variables. You can get a surprisingly broad deviation on 0-62 times of the same car with the same driver, if you measure it I'm enough different places at enough different times.

OP, manufacturers tried to prevent remapping (or rather, people remapping, blowing the engine then flashing back to standard and doing a warranty claim) by introducing a flash counter. However, all the remapper outfits these days claim to reset the flash counter, which would mean that no, there is no easy way to check if a vehicle has been remapped. However, if the stakes are high enough to make it worthwhile, it is possible to show if a vehicle is currently running a non standard map by side by side comparison. I'd suggest that idle curiosity isn't enough of a stake. If you are worried about insurance, you can just get it flashed to standard by a BMW specialist.

If you are thinking "I want a remap on a leased M140i but don't want to have to buy the car when they find out" then you may get away with it if you don't brag about it all over YouTube, Insta etc. (There was a YouTuber who did that with a leased BMW then cried salty tears when BMW wrote to him to invoke the "if you mess up our vehicle then you have to buy it at full RRP" clause.)

Edited by donkmeister on Thursday 2nd March 00:38

Hol

9,316 posts

230 months

Thursday 2nd March 2023
quotequote all
Rooted said:
Use a £5 Bluetooth dongle and the Torque app to see what the peak boost figure the car pushes out. Compare this with what the stock peak boost level should be.
s94wht said:
Take it to a tuner and they should be able to read the ECU
Both of these are good options, that will answer your question.


There was a post recently about someone who bought a mapped car from a main dealer that borked the engine. I left the thread when it started going off track and do not know how things ended, but the dealer was avoiding any warranty claim because an aftermarket exhaust had been fitted since purchase.

I’m not suggesting that will happen,- just that it has happened before.




Glenn63

3,958 posts

114 months

Thursday 2nd March 2023
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Main menu on I drive - vehicle info - sports display

If it says standard power it’s probably standard.



Edited by Glenn63 on Thursday 2nd March 10:36

Decky_Q

2,096 posts

207 months

Thursday 2nd March 2023
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I use a knock off delphi diagnostic computer (£60 from many online chinese businesses). It has a screen that shows if the ECU has been flashed and how many times. It's a brilliant pro level tool so if you ever need anything in future (wind back electronic calipers, access to abs/airbag/modules etc) it would be worth a little investment.

Antony Moxey

10,751 posts

249 months

Thursday 2nd March 2023
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Is there any reason why you can't ask the previous owner?

SteveStrange

7,778 posts

243 months

Thursday 2nd March 2023
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Antony Moxey said:
Is there any reason why you can't ask the previous owner?
Not sure if serious.

Bennet

2,133 posts

161 months

Thursday 2nd March 2023
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Crash it. If it has been remapped, your insurance company will let you know.

Antony Moxey

10,751 posts

249 months

Thursday 2nd March 2023
quotequote all
SteveStrange said:
Antony Moxey said:
Is there any reason why you can't ask the previous owner?
Not sure if serious.
Perfectly serious. The OP didn't say how he obtained the vehicle, it might have been a private sale in which case why not just ask?

Lester H

4,419 posts

135 months

Friday 3rd March 2023
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If you are familiar with similar cars, the answer would be “ Drive it “. The late Lawrence Pomeroy rightly said, “ if you have to measure an improvement, you haven’t got one”.( He was Chief Mechanical Engineer of Vauxhall, then Daimler and De Havilland.)

Edited by Lester H on Friday 3rd March 18:19

evil.edna

306 posts

100 months

Friday 3rd March 2023
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Terminator X said:
If the driving position is set at "gangster lean" then there is a high chance of a map.

TX.
You forgot to mention checking the steering wheel surface for excessive wear around the 12 o'clock position.