codes? check engine light

doogandougie · Post by **doogandougie** » 05 Jun 2011, 19:17

I have a 98 s70, is there a code reader that I can purchase? Or does it have to be a 99 or newer? Check engine light is on, and have a noise/slight vibration at times when braking that comes from the front end. The noise is only maybe once a day-seems to be the abs, but that light is not on.

copandengr · Post by **copandengr** » 05 Jun 2011, 22:01

All autombiles made after 1996 use an on board diagnostic system (OBD II). Somewhere inside the car (on my 1995 850 Turbo it is under the coin holder in front of the shifter) there is a connector where a code reader will connect. The location of this connector varies with the make of the car as well as the year but it will be anywhere from the front center of the dashboard (not on the dash, under it) or it may be under the steering wheel area. A code reader plugs into this and gives out the diagnostic fault codes the car's ECM (engine control module) has encountered based on data sent to it by various sensors located on various parts of the engine, transmission and many other parts. This code system is unversal and the code reader and the connector are the same for any car built in 1996 or later. The check engine light illuminates when there are one or more fault codes stored. These codes will remain stored for a given number of engine start cycles or until they are cleared, either by use of the code reader or by disconnecting the car battery for 30 minutes or more. Some makes, like my /dodge truch, will read out the fault codes by blinking the check engine light a given number of times after the system is activated by turning the key on and off a certain number of times. My truck also has the OBDII connector.

Auto Zone and some other parts stores will check your codes for free but they are not usualy permitted to clear the codes off the computer. These codes tell a mechanic what is going wrong. It is actualy a great system and as far as I am concerned, takes the guess work out of diagnosing virtualy all of the problems a car might develop over time.

My 1995 850 Turbo has two systems. It has a code reader located in the engine compartment, the use of which was discontnued after that model year and it is equipped with the OBD II system. You can buy your own code reader. They range in porice from less than 100 dollars to over 300 bucks. The more expensive readers also have the ability to keep a running check on the cars performance as it is going down the road. Such things as temps, enginr speed, electrical voltages and much more. This helps a mechanic diagnose problems so precisley that the old styl of "part swapper" mechanics are out of the loop now. This system also requires a mechanic have at least some training on the systems that newer cars use so he or she can understand what the data means.

The noise/ vibration you are experiencing is likely caused by warped brake rotors. Volvo des not reccomend machining their rotors. They say to replace them instead.

Post by **BEJinFbk** » 05 Jun 2011, 22:34

doogandougie wrote:I have a 98 s70, is there a code reader that I can purchase? Or does it have to be a 99 or newer? Check engine light is on, and have a noise/slight vibration at times when braking that comes from the front end. The noise is only maybe once a day-seems to be the abs, but that light is not on.

When you turn the key, but before you start the car,
do you see ABS and/or TRACS lights come on in "self test" ?
Just be sure they actually work before you get too far with this.

doogandougie · Post by **doogandougie** » 06 Jun 2011, 21:29

Thank you both for your time. Copandengr you were very helpful.

jgarrets · Post by **jgarrets** » 07 Jun 2011, 10:03

hello,
I failed inspection because of the MIL light not working, what is the easiest way for me to change this bulb?

Post by **Ozark Lee** » 07 Jun 2011, 11:17

jgarrets,

You need to remove the instrument cluster - it isn't as daunting as it looks but I replace them all (Except the Service Engine Soon light which I pull out and smash) while it is out. If you buy them aftermarket the lamps are around $10.00 / dozen as opposed to $10.00 each at the dealership.

This is for an 850 and it is more specific to repairing the odometer gears but the removal of the cluster all the same.

https://www.matthewsvolvosite.com/2005/0 ... ix-how-to/

More information is here:

https://www.matthewsvolvosite.com/forums ... =1&t=39752

...Lee

doogandougie · Post by **doogandougie** » 07 Jun 2011, 20:04

The ABS and Tracs lights do come on when starting. I believe it's the rotors. I found the OBD in the center arm rest. Thank you both for your help.