restricted performance

[mmslk248528]

Can anyone throw a light on this term which appears occasionally? I was in a traffic jam late the other evening for about an hour, engine running all the while! When I got on the the A1M the car was fine for about 30 miles, then the big yellow light came on, along with the message 'restricted performance'. I drove home carefully, but today the car is fine.

[Marineng]

I have seen this come up on a couple of different cars that I have owned in the past. The issue then was to do with the emission control equipment fitted to the car at the time. On my Diesel car a longer run cleared the particulate filter. My approach to all machinery is to carefully monitor the starting and operation making a note of anything that is different to build up a picture of good operation and therefore giving an early warning of a potential problem. Your observation here is a good start. I hope this helps as a general pointer.

Kind regards
Paul

[mmslk248528]

Great and thanks for your interest.

[andypryce]

Any fault codes with it?

[mmslk248528]

No fault codes. Recently had a new alternator, but I don't imagine that is part of it; I have sometimes heard it said that a new battery often cures many ills!
Tks for interest

[ptjs1]

mmslk248528,

You haven't mentioned what engine you have? Most restricted performance issues are to do with engine signals rather than any gearbox problem.

It's also unusual for it not to have stored a faullt code. Strange.

Certainly, the v8 petrol engines can be a little temperamental on MAFs which can cause this issue, but I'd expect the fault code to have been thrown.

Wait until it happens again and then check the fault code before you turn off the ignition (if you can)

Paul

[mmslk248528]

Hi Paul

It is a 2.7 diesel. I was unsure about which foruim (transmission or engine). Also thinking of buying a code reader - any recommendations?

Cheers
Harry Hall

[andypryce]

Start with a cheap generic OBD scanner, plenty on Amazon for a few quid.