[OutbackAndBeyondUK]

I decided to change the spark plugs on my H6, but as this was more time consuming than I thought it would be I first changed 3 plugs then decided to change the other 3 plugs the following day.
After changing the 3 on the right hand side of the car I noticed the 'VDC ON' light was illuminated.
After quickly having a look around the plugs I realised I hadn't reconnected a block connector, which connects a blue wire to a sensor on the bottom of the engine. I connected this and the 'VDC ON' light went out.
The next day I changed the 3 plugs on the left hand side of the car (had to remove washer bottle and battery). I put everything back again including the blue wire on this side. I started the car and the 'VDC ON' light is now permenantly illuminated ? and will not go out.
It's on all the time, from start up, during driving when cold and up to temperature.
No other warning lights are on.
My car does have the switch to turn off the 'VDC' but pressing this makes no difference.
All I have done is change 6 spark plugs and the air filter.
Previously, the 'VDC' worked fine and warning lights have never illuminated during my ownership.
I unplugged the blue wires (1 on each side) for ease of access to the plugs, these are now reconnected.
Could removal of the battery cause this ?
All the fuses are OK.
Any help would be appreciated though I'm thinking I may of hit one of the sensors when trying to get at the plugs.
Are the sensors fragile ?

 

[cardoc]

The blue wires go to the front AF sensors that assist in fuel metering. Are the plugs in tight? Did you hear or feel a snap?

The VDC Off light comes on when there is a performance issue. Check the temperature sensor on the front of the left side head just behind the oil filler neck and see if its connected. You may have bumped it and its not registering the proper temperature to the ECM and it thinks the car is overheating or too cold. What's the temperature gauge do with the engine running?

Scan the ECM for codes even though the MIL/CEL is not lit. If you have codes stored, what are they?

 

[OutbackAndBeyondUK]

Yesterday I went on a journey of 60 miles. When I set off the 'VDC ON' light was illuminated, after about 15 miles the light turned off then on again, this happened for a few minutes (intermittently on then off). Towards the end of my journey the light remained off. I've stopped and turned the car off and on again a few times, left it standing to cool down and the light has remained off.
I went out to the car this morning (after being stood all night) and the light remains off !
The temperature gauge remained in the correct position whether or not the 'VDC ON' light was on or off.
I'm going to go and check all wiring connections to make sure nothing is loose.
I do know that the rotors are warped and I need new pads, could this be an issue ?
The plugs are in tight (not over tight) and the engine runs/feels fine, I did not hear a snap !
Thanks.

 

[DavidPeab]

I believe the snap referred to relates to the plug wire caps snapping, popping, or clicking firmly onto the top of the plugs. Press the top of the wires firmly down until you hear or feel the plug wire end click onto the end of the plug.

The light may have been due to the battery disconnect and taken several driving cycles to reset. I would still recommend having the DTC codes scanned just in case there is another issue. An ounce of prevention is worth a pound of cure.

 

[1 Lucky Texan]

That car has coil-on-plug. maybe cardoc was concerned the ceramic on a plug was cracked on installation.

scan for pending codes as suggested. cardoc knows what he's doing, even more so with VDC as he owns one.

and congrats OutbackandBeyond on getting through a tough job!

 

[RedGeminiPA]

I'm not sure about Outbacks from across the pond, but the US models don't have a "VDC ON" light, but only "VDC OFF". Unless you're talking about the light inside the switch, then you could have a bulb going bad.

 

[OutbackAndBeyondUK]

I'm not sure about Outbacks from across the pond, but the US models don't have a "VDC ON" light, but only "VDC OFF". Unless you're talking about the light inside the switch, then you could have a bulb going bad.

Doh !
Yes, it's the 'VDC OFF' light !!!!!!
I changed the oil and filter today so had a good look around the bottom of the engine and had a good route around the top, everything was in order and the 'VDC OFF' light has remained off now for 2 days !
I have no code reader yet so thats on my shopping list.
Thanks guys.

 

[cardoc]

No. I was talking about the front AF plug, blue wire (DelPhi Sensor), and the Temperature sensor plug on Bank 2, the driver side head on LHD cars.

Could also be a wheel speed sensor has debris.

The VDC Off light comes on when the VDC is inactive due to an engine, transmission or ABS issue since it uses all 3 for control.

 

[OutbackAndBeyondUK]

No. I was talking about the front AF plug, blue wire (DelPhi Sensor), and the Temperature sensor plug on Bank 2, the driver side head on LHD cars.

Could also be a wheel speed sensor has debris.

The VDC Off light comes on when the VDC is inactive due to an engine, transmission or ABS issue since it uses all 3 for control.

The AF sensors on both sides are not loose or damaged, neither is the temp sensor plug.
I will check the wheel speed sensor soon as I am changing the rotors/pads.
One thing I did notice was when the light came on/off intermitently, I was turning at the same time ?

 

[cardoc]

Check wheel bearings.