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  View original topic: by the highway hot? motor or sensor 11
tosu Mon Jul 07, 2008 1:58 pm

stuck beside the highway in Superior Montana,
What are the symptms for a temp sensor 11 failure?
First off the fan got a bit iffy, so I hot wired it.
Then touring along i90 at the top of a long grade the gage shot up & the flasher was winking at me. Switched off & coaset 2 miles into a rest stop.
Thats where I hot wired the fan.
Ran fine for another 20 miles then needle jumped & flasher started.
Bently says resistance between terminals 2 &7 I show open circuit.
am waiting for a tow truck.
Is there a work around for the sensor?
could it be the thermostat or pump, since the gage jumps too?
would appreciate any knowhow help
Tony

foodeater Mon Jul 07, 2008 3:18 pm

Do you have enough coolant in the pressurized tank? These are the same symptoms that you get when the coolant goes below the sender in the pressurized tank.

tencentlife Mon Jul 07, 2008 7:03 pm

Right, check the coolant level in the pressure tank (inside the engine bay). If it's within 1" of the top when the engine is hot (it should actually be totally full so you can't even see the level thru the tank wall, but don't open it when hot to check!), then you could have a coolant level sensor problem. That's the item screwed into the topside of the pressure tank, with a plastic hex flange and two-pin connector. When it goes open circuit, either due to the level dropping in the tank (what it's supposed to sense), or failure of the sensor, or merely crud on the sensor pins that are immersed in the fluid so they don't sense the fluid anymore, it makes the LED in the temp gauge flash. Unfortunately, on the older vans like yours, it also makes the gauge needle shoot to the top of the scale, which is kind of silly since those separate conditions should prompt different responses so you can better tell what's wrong (they fixed that on the later models). But it got your attention, didn't it?

So, if the level of fluid in the pressure tank is at or very near the top when the engine is running, the problem could be due to the level sensor having a problem. There's a rundown of how to check it here:

http://www.thesamba.com/vw/forum/viewtopic.php?t=184096

The key thing is that you must turn the ignition off to reset the system after every test.

If that's all the problem is, you can try removing the sensor when the engine has cooled off, and wipe the probe pins clean. Sometimes that restores conductivity.

If that's no good, you could remove the sensor conector and bridge the connector pins with a paperclip or some wire. That would kill the LED and restore the temp gauge to normal operation.

Temp 2 goes to a low resistance when warm, I think it's a couple hundred ohms. Running open circuit (infinite ohms) on that is the same as the engine thinking it's very cold, so although I haven't tried this I think you could deliberately short that connector too if need be. That will make the ECU think the engine's warm. It just won't have any warmup regulation and may be difficult to start. Being that it's summer that factor is at it's minimum so that's a plus; you can probably just regulate warmup with your foot and drive gently for a minute or two and things should be fine after that.



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