Engine Indicator Light Illuminated - code P1521

[DJM]

Cover all the bases for ideas.
The missus took my TF to work at the beginning of the week and on the way home the Engine Indicator light came on. The handbook says:

Engine indicator (AMBER)
Illumination whilst driving indicates an engine fault
- If car drives normally, arrange a service appointment
- If light flashes and/or cr doe not drive normally, avoid high speeds and seek immediate assistance

I Borrowed an OBD reader from a kind ex MGTF owner. Connected up and only one code P1521 was found which, when looked up states:

P1521 Variable Intake Solenoid #1 Circuit Malfunction

but what exactly does it mean and will I cause further damage by continuing to drive?

The head gasket was replaced back in April 2010. With the snow and only being at home on drive at night I can't check, but I would have thought that if the blue/brown connectors were the wrong way round that would have been an issue before now.

If it's wiring, which do I need to check and how.

It's my main car so I'm in trouble without transport.

[adrianclifford]

The only experience I have had of the engine management light coming on was due to poor fuel. Since then I have always used only Shell or BP, in Europe if this is not available I'll use Aral Super. Every third fill up (or nearabouts) I'll use Shell V Power or BP Ultimate. Every service my trusted garage puts in a fuel additive/injector cleaner (ie every six months). Since then, no problems at all, in fact the car runs and feels better and the economy has improved. If I'm out on a lively run, I'll use better fuel all of the time so I can only suggest you check your fuel used (I hear so many tales of poor running and warnings by using supermarket fuel) and put in a bottle of injector cleaner.

I'm sure the more techical knowledge of others may help more.

[Geoff.F]

It all depends which Forum you wish to take advice from.
Indicator light convention is "Red" stop and fix it and "Amber" is a maintenance requirerment.
The engine indication is commonly the Lamda sensor/s. As Adrian has suggested, this is normally due to cheap fuel which causes deposits on the sensor. The Tesco Fiasco.
The recent cold and damp weather makes poor connections to fail therefore a clean and contact cleaner thru the engine bay may be the cheapest fix>
Playing with inexperienced OBD Readers will cost you more than 1/2 man hour with a good MG garage with the correct equipment and experience.
Geoff F.

[DJM]

Geoff,
sorry, but that's not correct. I have quoted what the MG handbook says with regard to the MiI - solid amber - arrange service check; flashing AMBER - stop and fix. Having seen both variations in the past and used an OBD reader perfectly successfully to obtain valid fault codes and corrected faults I am certain that both my interpretation of the MIl and the code are valid. I have only had success using the OBD reader as has the owner on his TF and the rest of us who have the cheek to borrow it.
As for a good MG garage - there aren't any in this area that I know of, and T4 may give slightly more detail but not change the diagnosis.

As for fuel and Lambda sensor - unlikely for 2 reasons
1) I only ever put "quality" fuel (Esso, BP, Texaco or Shell) into her since new in 2002
2) The MIl fault code does not relate to the Lambda sensor.

I suspect it is the wire between the brown connector and the ECU as this is the usual culprit for this fault code, but I was hoping someone may have more detailed knowledge and advice as to how to confirm this.

[mgtfnut]

Hi David. I've moved with you over from the BBS

Geoff has a point - clean the blue/brown plugs (also the cam sensor plug nearby) as a change in the weather might have brought this on after having been disturbed recently. You never know, it might be that simple

A full T4/Testbook check would be better.
Jerry

[DJM]

Jerry,
I remember when the BBS was a real hive of activity in the 90's. I was a regular poster and reader then, but these days ....

I don't disagree that it may be the connections - in fact I hope it is, but the fault code is fairly specific and I had hoped someone could identify the exact area to check (blue or brown connector, and which is the wire which seems to be particularly suceptible to failure and its route to the ECU).

Where I disagreed with Geoff was that the MiL colour coding he was stating was incorrect and the statement about wasting time with "cheap" OBD readers. Since 1996 with my MGF and TF I have spent a considerable amount on T4 checks (mostly with the current TF I might add) and almost universally they have been a complete waste of money. They have either not identified the fault, or provided no further information than that I already knew using a good quality (or in one case a cheap) OBD reader. Admitedly sometimes this is because the monkey working T4 had no idea what the results he was getting meant or what to do with them. Whilst I think the cost is extortionate and probably not worth it, if there was a competent MG specialist in the area with T4 capabilities I would probably take it there as i have little time and no available garage to properly diagnose myself in temps greater than zero and without snow. What I need is Tech-speed, Dave Andrews or Rally Matt to move south

I am also not bought into the "Tesco Fiasco" conspiracy. Although I don't use it, SWMBO does and has since 2000 in the freebie with no ill effects. I also know many other F/TF owners who are happy with cheap fuel. Add into that my cousin who works for one of the major refinaries giving me a good insight into the differences (about 10p per litre mainly) between "premium" brand and own brand petrol and I feel urban myths coming on.

That said, thanks for the replies they are all appreciated.

[Stuart Dunn]

Hi There,

Just an Idea for you, It could be your IACV, Idle Air Control Valve.
Situated on the back end of the plenum nearest the throttle bodie, this is the bypass for the throttle bodie which allows the engine to idle whilst the bodie is in its fully closed state. This is also responsible for increasing revs whilst at a standstill if the alternator becomes under more load EG. Fan comes on, or steering EPAS unit switched on, also Aircon whislt car is stationary, and act's alongside the engines Anti stall function.

With this cold weather might have caused it to stick, flagging up your fault.

Just another line for you to investigate. This is a variable air valve in the air intake.