03 Volvo S60 Sedan AWD

I recently purchased an 03 Volvo S60 AWD. 2 questions. I need to get it smogged and the Smog guy tells me I need to drive 200 hundred miles and come back so the computer can reset or something like that. He also tells me I need to keep the fuel gauge between 1/4 and 3/4. Can anyone give me insight on that? Also my wife had a minor accident in the car about two week ago. She was driving on a wet canyon road around a curve at about 38 mph. The car suddenly did a 180 in the direction she was turning and she ended up on the shoulder of the other side of the road facing in the opposite direction from her original direction. Does anyone know why that would happen? The car has AWD, but at that time only the rear wheel drive was working. I have noticed that when I make a sharp turn the car wants to turn even sharper, but this was a gentle curve. Any ideas? Thanks

Your smog guy sounds like he knows what he’s talking about. Undoubtedly he hooked up his scanner and determined that one or more of your monitors hasn’t run to completion. The evap monitor isn’t easy to complete. The evap monitor will only run at certain temperatures and the fuel level must be between 15% and 85%. So don’t run on fumes and don’t top off.

Here’s my advice for completing the evap monitor. Fill fuel so that the tank is about 2/3 full.
Tomorrow morning, start the car and let it idle with no AC for about 5 minutes. Then drive normally to work. Steady driving, no rapid acceleration. For the next few mornings, let it idle for 5 minutes before setting out. And don’t let the fuel level get too low.

I suspect the 200 mile thing has to do with the catalytic converter monitor. Steady driving at freeway speeds should do the trick. I’m talking 65, not 85. Cruising, not racing or weaving in and out.

I am curious how and why this S60 AWD ended up solely RWD?

My research indicates that the final drive of this Volvo is primarily front wheel drive with a hydraulic actuated, multiplate clutch transfer for rear differential. The transfer case takes the drive off the front differential housing and sends power to the rear differential. The amount of power transfered is controlled by the traction control module and the difference between the input shaft speed (front wheel rotational speed) and the output shaft speed (rear wheel rotational speed) through that multiplate clutch. The Dynamic Stability Control also gets involved in the transfer as well as active differential wheel brake control.

I suspect that your oversteer condition has something to do with the lack of front wheel propulsion and the DSC getting confused because the global system was not designed for the conditions you are presenting to it i.e. rear wheel drive only. Also the mechanical roll control through antiroll bars would be designed for AWD propulsion.

I assume that you have checked the tire inflation pressures and they are spot on. I also assume that you have inspected the tires for overall wear; abnormal wear conditions; and circumference uniformity. It probably would be wise to have a four wheel alignment done as the “minor accident” might have done more damage.

Hope this is of interest to you.

Did you have this car inspected before you bought it? Sounds like it needs a going over front to back.