Help with computer codes

Gilbert · Post by **Gilbert** » 11 Feb 2006, 19:55

Hi, I am a new owner of an old 1992 940 4 cyl non turbo ( vin numbers 6 and 7 are 88 ) The Chilton's manual prints in one page that the fuel system is a LH 2.4 and in the next page it prints that it is a Regina.
Check engine light comes on
I read the code the test cable plugged in number 6 and I get 1-4-3
The only place that I find this code is in the motronic code description and it means "front knock sensor signal absent or faulty" I can find only one knock sensor in this engine.
I read the code the test cable plugged in number 2 and I get:
3-1-1 spedometer signal missing, also the speedometer and the cruise control were not working , replaced the instrument panel and now the speedometer and the cruise control work but I still get the same error
any suggestions?
2-3-2 self adjusting oxigen sensor not working , what do I do here?
1-2-2 air temperature sensor, where is that thing?
Please, any and all the help is appreciated
Gilbert

wojeepster · Post by **wojeepster** » 13 Feb 2006, 19:10

http://www.troublecodes.net/Volvo/

wojeepster · Post by **wojeepster** » 13 Feb 2006, 19:24

On the knock sensor check the connection since you only have one that is the one they mean. To test it's function connect timing light to any spark plug wire and with engine running tap a spot near the knock sensor with the handle of the screwdriver. dont get caught in the fan, belt etc. You should see the ignition timing retard when you tap on the engine. If this doesn't happen then maybe you have a bad knock sensor or a bad ground, wiring etc.

Measure signal wire from oxygen sensor with a digital volt meter only. Should vary from .1v(lean) to .9v (rich) If it is sluggish or does not move at all you have a bad o2 sensor. I replaced mine and the car runs better (at 237k) they say to replace every 60k. $187!

Air temp sensor is usually located near the airbox and looks like a coolant temp sensor but measures air temp. They are usually reverse coificient thermistors which means they have a high resistance when cold and a lower resistance when warm. They have a very large effect on the fuel injection. Compare with book specs measure and replace if it needs it.

don't know about the other stuff. but since it is working but the signal is not getting through it sounds like a bad connection to me. I have found volvo tech publications useful although expensive. but they show you where all the relays, grounds etc are. $27

Gilbert · Post by **Gilbert** » 14 Feb 2006, 05:41

I found out it is a Regina fuel system, it's the only one that uses an Air Temperature Sensor instead the Air Mass Meter. I tested the air sensor and it seems to work fine, still have to check the cables.
Somewhere I read that leaky injectors and bad fuel regulator can set the code 232, I have another engine and I will swap those to try
I had replaced the speedometer and the computer gets the signal from the same place that the cruise control , and the CC is working so I have to check the cables also.
Can a computer be bad?
It is missing speedometer, knock sensor, Air Temp meter, all those signals, what are the chances of all those cables being bad instead the computer.
Thanks for all the suggestions.
Gilbert

Gilbert · Post by **Gilbert** » 20 Feb 2006, 18:25

Replacing the speedo did fix the 311 code, I swapped the injectors with some blue ones ( I think they are for turbo ) and the engine was not working properly and it gave me an oxigen sensor error. In the swap I notice that the ground cable that goes from the firewall to the manifold was broken, so I put the original injectors back and fixed the ground and all the fuel injection errors are gone.
for the knock sensor I found that the cable was broken near the connector, so I fixed the cable but I still have that error.
Will any other knock sensor from another b230f or turbo work ?