Hi guys, I'm having some strange issues with my 2006 automatic TL with about 123000 KM. It all started about a month ago, I was making a regular left turn when all of a sudden, both the VSA and CEL lights came on, the D was blinking green, and the temp gauge went all the way to hot. Parked the car on the side of the rode, turned it off for about 30 seconds, turned it back on and everything was normal except that the CEL was still on. Got the codes checked, and I got things like p0138, p0158 (O2 sens codes) etc.

Took it to the dealership and they said that all the codes were generated by low voltage, but they didn't say exactly what was causing it and I shouldn't worry about it. The symptoms will usually arise every 3-4 days, the CEL will come out of nowhere, VSA light, blinking D, and the temp gauge will go either max hot or cold. A simple restart fixes everything except the CEL, which will go away on it's own within a couple of hours of driving/starting the vehicle. I have had the battery, O2 sens, and spark plugs changed but the problem still occurs. The only difference in the cars performance when the VSA/CEL are both on is that it seems more difficult for the vehicle to change from 30-40 km/h to 50-60 km/h but other than that, it drives normally. When it's just the CEL on, car drives perfectly normal.

I've been searching around the forum and can't find a clear answer to this problem (the car has never gone into limp mode btw). Last time I got the codes scanned (2 weeks ago), I was getting p0118, p0113, and p0406. I was wondering if anyone else had ever countered an issue like this or may know the solution?

 

Anyone have any ideas or guess? anything

 

I would inspect all of the battery cables and grounds. Make sure there isn't any corrosion on them (or in the cable itself by the terminal). If the cables have corrosion in/on them, or if the grounds aren't making good contact, a brand new battery will not make any difference. You can follow the black cable to find the grounds on the vehicle. Usually there is at least one that grounds to the body, one to the engine and one to the transmission. There may be a post (use search) somewhere on here where someone points out where they all are. Find them all and clean them well with a wire brush (both the terminal and grounding location).

It wouldn't hurt to check any other major electrical connections (ECU ect) and make sure they are clean and making good contact.

A bad/weak battery or bad grounds/connections can cause some pretty odd electrical issues.

 

I'd like to update this because I am sure I have solved the problem, and it's really weird. I found out that I had way too much pressure in the tires (over 290 kPa on every tire... LOL). So I brought it back down to what the owner's manual suggests, and I have not had any problems in over a week now.

 

Some guy posted the exact same thing a few days ago but his was high voltage. Low voltage might mean not enough power to activate the radiator fan which explains why the temps go up. As for the source of the problem, might be the fan relay. Had a similar problem with my Jetta. The difference is my CEL never turned on. Some mecanic told me to replace the fan control unit, didnt do anything. Turn out the fan bearing was dirty and the friction was stronger than the force it took to turn the fan. But in this case, its a electrical problem