I have a 1994 Volvo 850 sedan, as I was waiting for the stop light to change, my RPM shot up from idle to 3,000 RPM. I shifted my automatic transmission into neutural, and the RPM speed shot up even further. After I got my car back home, I noticed that the "check engine" light was on. I open the hood and located the "diagnostic unit" next to the windshield washer reservoir and I extracted the following code (counting the flashes from the LED light). The code was "2-1-4". </P>


The question is, does anyone know what this code refers to... I think it is the "RPM sensor", but not sure. And if it is this sensor, how difficult is it to replace. </P>


Thank you in advance for your help.</P>


Mike</P>

 

According to the Haynes repair manual if you have either the Fenix 5.2 or the Motronic 4.3 systems 2-1-4 does in fact signify afaulty or missing RPM sensor. I'm sorry to say that I am not sure where the sensor is located. Good luck.

 

Follow up on my problem, thank you for the response. The solution turned out to be the MAF sensor.

 

A-ha, finally after trawling all the forums, someone with a similarproblem to mine! I have a 96 850 T5 estate. Occasionally when decellorating I get the engine revving to 3000 rpm and staying there, even if I am braking with no input on the throttle and if I have the clutch in.

I have an OBD II code reader on order when I get some readings I'll re post. is it a Mass Air Flow sensor? Difficult to locate / change? Thanks in advance.

 

http://volvospeed.com/vs_forum/index...howtopic=46991

Perhaps that'll help you..

 

Nice tutorial, I'll get stuck in tomorrow. Update on the OBD II reader, it's arrived but as I have a european volvo it's not OBD II compliant. A warning to anyone else looking to buy an OBD II reader - MAKE SURE YOUR CAR IS COMPLIANT- There should be a plate / sticker under your bonnet somewhere that will state OBD II, Just because the 16 pin connector is present does not mean your car is fully compliant. The 1996 volvo 850 T5 I have has the connector but the reader could not find any one of the five software protocols. I've just spent 80 bucks and it doesn't work.

 

^Can you return it?

You should have asked us first! You need a special "volvo scan tool" to read all of the codes. Your generic OBD-II will not give you some of the more "advanced" codes.

 

Hello mate,

Greetings from Yokohama, Japan.

For your future ref:

http://volvospeed.com/maintenance.shtml

Engine Codes:
http://volvospeed.com/Repair/a2.html

Transmission Codes:
http://volvospeed.com/Repair/a1.html

ABS Codes:
http://volvospeed.com/Repair/a3.html

Motronic 4.3 is used on B5234T (2.3L Turbo), so I believe Fenix is used on B5254S (N/A).

As to the OBD-II scanner, Axelm or Tech would be able to tell you better answer, if they are available. If returnable, I would return it. If not, I wonder if you can find an adapter of some sort. For $80, I assume the scanner isn't programmable or is it? You may want to do some search at:

http://www.actron.com/

Or, as a last resort, make your own OBD-II-to-OBD-I tester (See attached pic).

I hope this helps.


JPN

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ok guys the saga continues. My wife is going spare " just take it to the dealer" she says, oh no no no. it is now a matter of principle. The dealer wants close to $160 just to read the code and tell me what's wrong!

I've had a mobile diagnostic / tuning guy come and try to read it but he had no luck. He did check the emissions though and they are spot on. We cleaned out the idle air control valve as it was really dirty but the car still started over revving after it was left running in idle for a few minutes.

I'm now thinking it may be the throttle position switch. I disconnected it today and started her up. First try it didn't start at all (similar to original fault) and on the second attempt it started but the revs were all over the place. ($120 to replace)

I've found a contact at work that is a bit of a whizz and has a laptop loaded with software for this stuff. he's going to give it a whirl tomorrow. I'll keep you posted on the results.

As for the reader I've bought. It's a tool,I've got it and it'll come in handy in the future I'm sure. I'd rather spend a fortune on kit than be ripped off by the dealer.

If I get no joy tomorrow then I'll clean the MAF (thanks RedTurbo850) then start making educated guesses.

By the way this may not just be for volvos but apparently if you fit a non standard radio on some cars then the OBD II reader may not be able to read properly, just a thought for anyone having trouble reading codes.

It's been a long one I know but just a bit off topic-JPN thanks for the links etc and Yokahama.... I like. I had 2 weeks there back in '96 and Japan was awesome. You still work in the aircraft industry? I'm an Aircraft tech myself which is why I'm so against paying some monkey so much money just to tell me what is wrong when I know I will be able to fix it myself!

 

Hello mate,

For RPM hunting all over the place, many people have reported that it was due to a faulty MAF sensor. The wiring to the sensor has one sharp bend by the sensor, preventing good electrical path. With the engine running try wiggling the wire around the bend to see if the engine responds. Here's a guidance:

http://volvospeed.com/Repair/maf_secure.php

I've also attached a pic that shows you where engine control sensors are located at, and I've circled MAF &amp; RPM sensors.

I've spent approx. 11 years in the United States continually, including much of my formative years, and I feel that I am absolutely done with Japan. I plan to continue working in the industry but I cannot work on airplanes in Japan (except for one U.S airline; other airlines seem to outsource it to someone else) due to a number of discriminations. I'm 33 and considered too old at Japanese airlines, and I have colour blindness which is negligible but they only hire people with perfect health record. I've been trying to find a way to return either to the United States or Canada (would love to work &amp; live in England, if I can do so legally) but so far not much luck. It is a shame, that many citizens &amp; permanent residents in the United States entered the country through marriage/connections with relatives, and many of them cannot even communicate in English efficiently. For me, this is a joke.

While I was in Chicago, I worked at a small company at O'Hare, mostly serving British Airways and I really enjoyed working with BA. One of the BA engineers told me that England is also having a huge problem with immigrants.

Anyway, I hope the problem would be fixed soon and your wife'll be happy.

Cheers,


JPN

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