click here for info how to read fault codes on you car munual and here is the list of fault codes for reference to you
Locate the diagnostic service interface. This is a little black plastic box located near the shock tower on the driver's side engine bay. This varies slightly from model to model. The protective cover must first be removed.
Turn the ignition switch to the ON position, but do not start the car.Locate the jumper lead (the plug stores in a pocket in the cover) and insert it into the socket number 6. Press the diagnostic button on the interface for about a second and a half, about the time required to say "Volvo Corporation".
The LED will begin flashing, with the flashes representing diagnostic codes. Flashes are presented in three groups of flashes (approximately 0.5 seconds), separated by a slightly longer interval: first, second and third, representing the first, second and third digit of a three-digit code. Have a look at this short video showing the LED flashing.
If the code presented is 1-1-1, that means that the register is empty and there are no fault codes stored. A non-1-1-1 fault code represents a specific trouble, which can be decoded using the associated table.After a fault code has been recorded, press the button again, saying "Volvo Corporation".
The next code is displayed or, if there are no more codes, the first code is displayed again.
When all of the codes have been recorded, the buffer can be erased by first pressing and holding the button for five seconds and then releasing it.After a brief pause, the LED should again light. Press and hold the button for an additional five seconds and then release. The LED should go out.
if dont work than in email send me your email make it xxx @ xxx.com spaced out at @ or it will not post here for me to see it
OK, now I have a few codes:
2-1-4 RPM sensor signal absent or faulty - Is this the same as a crank position sensor? Should it be replaced?
2-3-1 Fuel trim to lean or rich in part load range - What does this mean?
3-1-2 No knock enrichment from 01 signal - What does this mean?
the part is between trans and engine if you look at the back side of the engine use strong flash light and look for black wire and sensor look here in picture this is from under the car i mark with red were it is you can see it from top and remove it from top
But I still have the questions about the codes and what thay mean:
See above for the questions.
So 231 and 312 - bad mass air flow sensor, fuel pressure, vacuum leak, or oxygen sensor, or poor ignition. I can check these. what do you mean by poor ignition?
Is an RPM sensor a Crank Position Sensor?
poor ingition if the car is not running right where you dump to much fuel in exhuast making oxygen sensors read wrong like check spark plugs .ignition wiires
the fault code you have is for the part in picture i send you .
the rpm sensors/crank sensors one sensors is used for both monitoring.