Engine Management Light/Fault Codes

Hi there.

Have been monitoring the forum since buying my first Volvo, a 99 S70 T5, a couple of months ago and can't seem to find an answer to this problem. Hope someone out there can help and please don't laugh at the "daft laddie".

Not long after buying the car the engine management light came on. Despite the car seeming to run as well as before, I took it straight to my local Volvo dealer (Murray at Sighthill in Edinburgh) who said the fault codes 260A and 261A meant the Air Mass Meter was knackered. As they wanted £249 + Vat for the part and £60 + Vat for fitting I asked them to reset the light and I would try and source one myself. In the meantime the light came back on but has gone out a couple of times (once for three days when it was really cold). I have managed to get a secondhand MAF from Lea-Valley in London for £88 + Vat and this has improved the acceleration but the light is still on.

Couple of questions...

Should I have reset the Engine Management light (and if so how)?
If it's not the MAF and the codes are wrong, how will I find out what is causing the problem without having to pay all my wages to the Volvo garage?

I know this is a bit long winded, but I'm getting a bit confused with it all.

Thanks,

Steve

hi theres a volvo sevice bullitin out regarding the maf sensor electrical connector, wiring can be badly routed leading to chaffing, high resistance across pins etc causing spurious fault messages, might be worth having a good inspection of the wiring /connector

[Traduk]

Steve,

From what I have read and personal experience the way to get rid of the light is to disconnect the battery for a few minutes. PLEASE make sure that you know the radio code before you do it.

It does not reset the stored code but general opinion has it that the ECM will poll the sensor for a number of starts, hours run or mileage and if no new sensor errors are detected will eventually clear the code... could take weeks or months but apparently it will be cleared at some stage. It doesn't really matter how long the code stays providing it is not triggered again and you tell a garage if a diagnostic is done on Vadis.

If it is going to come back it will do so in three days to a week, albeit that may depend on use patterns. Even if it does come back it may not represent a major problem because I had an O2 sensor changed a month ago and Volvo have changed the design and my '99 V70 T5 may have needed a Vadis software upgrade to facilitate the new sensor. I do not know if the MAFF sensor has been upgraded.

Traduk

[Chris_Rogers]

Codes 260A & 261A relate to long term fuel trim at loads higher than idle, basically the ECU is having to go to it's pre-set limits to maintain Lambda = 1

Possible causes:

Air leak in Induction or Exhaust system
Wrong fuel pressure
Injectors leaking
Faulty MAF sensor
Faulty Lambda Sensor
Engine Oil contaminated or level too high.

As code 268A, which relates to fuel trim at idle, does not seem to be logged and you have already replaced the MAF sensor I would start looking at the other things on the list, are there any drivabilty problems or high fuel consumption as well?

If you have and OBDII scan tool I would look a the fuel trim and Lambda Sensor output values both at idle and cruising.

Have followed Andy and Traduk's advice re: checking wiring and resetting the warning light. Have not had a chance to drive the car since, but the light is out for now.

Chris,
Fuel consumption for previous owner was 25-28 average with 32 possible on long runs. I managed 30 the first week I had it and have been averaging 25ish since the light came on. Car felt very lumpy until engine warmed up, then ran as smoothly as a five will run. The turbo lag is back (was gone when the light was on) as the car is presumably getting the right amount of fuel at the right time? I don't know what the drivability is meant to be like as I test drove it with the owner's wife sat next to me (advanced driving instructor) and the first 2K miles my own wife was sat in the suicide seat and my wee lad in the back. Not conducive to giving the car a good leathering to see if it's going OK. At low speeds it seemed fine but there was a flat spot at 4K revs in third when accelerating hard and changing up from second. I haven't had a chance to see if that's gone yet. Will keep an eye out and let you know.

Don't think the oil level is too high as it's 2/3rds on the dipstick and looks fairly clean.

Where would I obtain an OBDII scan tool?

Thanks for the advice.

Steve

[Chris_Rogers]

"Where would I obtain an OBDII scan tool?"

What a question!

Like everything it depends what you're prepared to spend.
If you have a laptop PC I would suggest the cheapest option is to go for one of the PC based tools. These can be used on a desktop PC with the limitation that you have to be able to connect to the car. You can use a lead up to 50' but clearly you can't record live data while driving with this set-up!

These day's if you hope to do anything with a car beyond basic servicing I think you have to accept that you will need some sort of diagnostic scan tool.

Volvo, in common with most European cars, use the ISO 9141 protocol so given a choice of interface leads choose that one.
If you have other cars, at lot of Volvo owners also tend to have VAG cars in the family, then buy an interface lead that will cope with VAG-COM (The VW scan tool program) as well. The supplier should be able to advise you.

Bear in mind that OBDII/EOBD is generic and covers only emissions related diagnostics, basically only engine and auto gearboxes. The fault codes are also generic and may not be as accurate as the manufacturer ones we have been discussing.


The OBDII tool I use can be obtained from the US directly at:
http://www.obd-2.com/

UK supplier can be found at:
http://www.onboarddiagnostics.co.uk/

The suppliers above & below can also supply a PC based Volvo fault code reader program (Vol-FCR) which will cover most system in all models between '96 & '98 including service light reset. There is some coverage for later cars but not for your ME7 engine ECU which is OBDII compliant anyway.

You could also try:

http://www.dntn.co.uk/home.htm

[Traduk]

Chris,

If you read back through the thread you will find that the vehicle is '99 which was when the VADIS only Volvo ECMs came out.

His vehicle is the same year as mine and the garage that sold me the car and maintain it, have four times and at their expense (warranty work) taken the car to a main dealer for VADIS diagnostics. They have Volvo code readers but none are of any value for a '99 and newer Volvo.

Traduk

[Traduk]

>>Where would I obtain an OBDII scan tool?<<


Steve,

They are no use to you therefore you do not need to find out ;).

From '99 onwards Volvo used ECM's which are only readable by VADIS diagnostics which are computers which can link to Sweden (Volvo HQ) and are mainly only found in Volvo main dealers. There is talk that competition and fair trade laws may force Volvo to allow use by non directly franchised garages and I hope that it is true and comes to pass or my current Volvo is the last I shall ever own.

Traduk

[Chris_Rogers]

Well I have one of these cars and I can assure you that an OBDII scan tool does work on them. That's whay I gave the advice.

[Traduk]

Chris,

What year is your car?. I am interested because the garage where I have mine maintained which is a non main dealer but deals with hundreds of used Volvos per year cannot extract and decipher codes from post '99 vehicles. Almost every Volvo forum I frequent on the web gives answers of up to '98 only as you did in your own reply, earlier in the thread.

If you have something which can extract codes and a translation which can turn them into something meaningful for diagnostics I think a lot of post '99 owners may well be interested. I know I would :)

Manufacturer of scanner and model number would be helpful.

Traduk