Engine Management Light
 

Hello my T5 has been off the road for about 7 years due to an MOT failure: Co high, Exhaust emissions carbon monoxide content at idle excessive. This was in 2012 when it was given to me as a spares vehicle. The tester said it was prob the Cat or a sensor. I made a code reader as described by Jod and got a read out soon after of 2 3 1 : Long term fuel mixture to rich or too weak. Due to my financial circumstances, time etc. I did nothing with the car, other than start it up occasionally & move it about my drive to keep the brakes free.
I've now decided to get it back on the road and apart from a few niggling things it seems to still run well & started first turn of the key, after about 6 months.
However, the engine management light has now come on, the one that is an upside down Y in a green triangle on an orange background. I have run the codes using Jod's DIY reader and it come sup with 4 1 1. Which the manual says is Throttle position sensor signal outside voltage range.Is it likely that the sensor is defunct after being stood for so long? If so the Haynes module tells you how to remove it, but not what it looks like or its exact location. A photo or advice as to the problem would be much appreciated.

I think that light may refer to an oxygen (lambda) sensor...

No it doesn't, it's the engine management light, which comes on when ANY fault is found with the engine management system. What part of the system is faulty can only be determined by reading the codes (which the OP has done) which will usually point to the area where the fault lies. The lambda sensor is only one of many areas that may be faulty, and in this case lambda isn't indicated, but throttle position sensor is.

https://www.google.com/imgres?imgurl...act=mrc&uact=8

OP says he has an upside down Y in a green triangle...Lambda sensor.
Also says he has code 2 3 1 fuel mixture

IMHO I would still consider replacing O2 sensor

Sorry, but that light is a lambda light and not the EML. It is related to fuel system/emissions. The codes Steve has pulled are also pulled from the fuel system pin (A2).

Steve, your initial code of 231 is almost always a faulty vacuum line (I've had two in the 18 months I had my T5). You can either check them using a vacuum gauge or a smoke machine. Alternatively, given the car has been sitting a while and they're quite old now you can go through and systematically replace all the vacuum lines.

O2 sensors do go, but they normally only die as a result of another underlying problem causing a too rich fuel mixture over a long period of time. I'd definitely be looking for an underlying cause first.

Regarding 411, TPS is relatively easy to test. Here is one short guide on it, but there are plenty more out there.

https://www.matthewsvolvosite.com/fo...ic.php?t=47868

Throttle Position Sensor.
 

Thanks for all of your input. I am still at a loss where to start with diagnosing the problem, though. I did take the TPS off and clean it using proper switch cleaner & clean the throttle with carb cleaner. While it was off I ran a test as shown on U Tube and it seems to read correctly ohm reading starting at around 1 & going up to about 2.3 (this is ok according to the video). But EML remained on, has it stayed on cos I have not cleared the code? However, the other video I found tested the TPS in position with engine running & the readings were from less than 1 upto about 4.5. Am I being thick?
I am tempted to swap the TPS from my other working 850 to see if this cures the prob.

You will need to clear the code(s) but I guess they will return if the problem is not fixed.

As above, even if the fault is fixed the code needs to be cleared for the lift to go out. If it comes back on then you will know the problems still exist.

Clear the codes, give it a good hard run to get it really up to temperature, may help to clean exhaust system...
Worked for me.

Oh, and try to use good quality fuel...

Well thanks for all of your suggestions. I cleared the codes & the EML went out. So feeling brave I took it for an MOT and it failed, but not on the original fail 7-years ago before I took it off the road (CO too high), but on a worn tyre (inside edge where I didnt see it), a bulb above the front indicator (works intermittently) and a dust cover to the anti-roll bar linkage. So big result. Not sure why it failed on CO emissions originally, although I did get a reading back in 2012 of 2:3:1, which points towards too rich a mixture. So the moral of the story is if your car fails on emissions, just leave it for 7-years & try again!!! Oh the only other thing I did was pour a tin of Cataclean into the tank & take it for a high speed burst on the ring road 10-mins before the test, so who knows.