My 99' Volvo V70XC AWD has white exhaust smoke coming from the tailpipe. on 1999 Volvo V70 XC

ECM 4801 (Three Way cat conv (TWC) efficiency, bank 1 ECM 4308 Leak Diagnostic, major leak ECM 9400 (Brake pedal sensor- signal too low (faulty) (ECM 9400 this will be corrected today w/ new brake pedal sensor from Volvo.. Those are the three codes being read currently. Check Engine Light comes on and scanner states "Loose Gas Cap". ETS light is for the ECM 9400 (brake pedal sensor). I noticed some white smoke came from my exhaust while the car shifter was in the D (drive) but I was completely stopped talking to somebody. When I took stepped off the brake is when the car smoke came out. I've seen this every once in awhile but have not seen any smoke while car is parked and running. Help with codes diagostics and what could be the issues. Also, what to do?

by in Concord, NH on September 01, 2010
1 answer 3 comments
ANSWER by on September 01, 2010
Excellent information! This is really good. The Pedal Sensor will address the 9400 DTC, and hopefully the gas cap takes care of the 4308. The smoke and 4801 code are more difficult to determine. Have you been losing coolant? Has the engine overheated ever? Was the engine warmed up when you saw the smoke?
COMMENT by on September 01, 2010
I had put some in about a month ago but the level if it has gone down then it hasn't by that much.. I never got any warning lights about coolant or anything other than what was detected earlier.. I see leaks in various spots under the engine right side, left front, middle left rear of engine.. I tighented two loose claps around hosing elements leading to the drivers's side, middle left, in the rear (closest to the steering wheel) but I'm wondering about seals and gaskets leaking.. Not sure where turbo return pipe is located nor the intake manifold gasket..?
COMMENT by on September 01, 2010
The turbo return pipe is at the back of the engine, attached to the turbo and goes to the oil pan. Intake manifold gasket is between the intake manifold and the cylinder head.
COMMENT by on September 01, 2010
Sorry.. no , the vehicle has never overheated...These are both common leaking problems w/this vehicle..could either or both be causing the smoke in my exhaust? I appreciate all of your knowledge