# 00779 - Outside Air Temp Sensor (G17) - Golf MK5 GTI



## dave1814 (Jan 5, 2017)

Hi all!

Just wondering if someone can help me with the following fault code...


Address 17: Instruments Labels: 1K0-920-xxx-17.lbl
Part No: 1K6 920 962 
Component: KOMBIINSTRUMENT VDD 1012 
Coding: 0007403
Shop #: WSC 00671 067 57207
VCID: 6ED24880796EDD322B-803A

1 Fault Found:
00779 - Outside Air Temp Sensor (G17) 
010 - Open or Short to Plus - Intermittent


My outside temperature reading is crazy on the dash, it ends up in minus figures when I drive the car (when it clearly isn't) and also plays havoc with the A/C!

So far I have tried...

1. New genuine ambient temperature sensor
2. Cleaned all connections
3. Reset the all faults using VCDS
4. Continuity test using a multi meter - which passes

Is it possible this could be a faulty Instrument Cluster? (that's about all I can think of from googling!

many thanks,
Dave


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## GTI's (Nov 27, 2011)

"4. Continuity test using a multi meter - which passes"

What passes the sensor or the wiring from sensor.


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## dave1814 (Jan 5, 2017)

Sorry I should have stated it was the sensor I tested. Which was probably a pointless test!

When I connected a multi meter to the connector plug with the engine running I got 4.97v reading. Not sure if this proves much though! 

Unsure of my next steps now ?

Thanks 
Dave


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## GTI's (Nov 27, 2011)

Based on the dtc you have an *intermittent* wiring problem. What month and year was your GTI made I can get the Wiring diagram for your G17 sensor.

00779 - Outside Air Temp Sensor (G17) 
010 - Open or Short to Plus - Intermittent

Testing for Short to Positive.

Prerequisites: 
- Ignition is off
- Disconnect the component(s) connector(s)
- Check wiring diagram and make sure no other components are on the circuit
- Disconnect the controller connector
Testing details:
- Set Digital Volt Ohm Meter (DVOM) to DC Voltage
- One DVOM meter probe to battery negative (-)
- Other probe to wire connection that is being tested (either end)
- Wiggle the harness
- Voltage is less than 0.2-Volts is acceptable
Repair details:
- Search and find the wire short and repair
- Or install an overlay harness



Testing for Open Circuits.

Prerequisites: 
- Ignition is off
- Disconnect the component(s) connector(s)
- Check wiring diagram and make sure no other components are on the circuit
- Disconnect the controller connector
Testing details:
- Set Digital Volt Ohm Meter (DVOM) to Ohm setting
- DVOM meter probes each end of the wire to be tested
- Wiggle the harness
- Resistance of 3-Ohms or less is acceptable
Repair details:
- Search and find the open/damaged wire and repair
- Or install an overlay harness


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## dave1814 (Jan 5, 2017)

That would be fantastic thanks! 

Build date is 06/2005 I think! 

Thanks again!


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## GTI's (Nov 27, 2011)




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## dave1814 (Jan 5, 2017)

Thanks! But sorry that's confused me. All this is a bit new to me. 

So for the first test one end of the multimeter goes to negative on the battery and the other goes to one of the wires that the sensor connects to? Again. Sorry for being an idiot!


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## GTI's (Nov 27, 2011)

You need to disconnect the plug at the G17 sensor and instrument cluster connector then test wiring.


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## dave1814 (Jan 5, 2017)

Makes sense! Will try this and let you know how I get on. 

Thanks!


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## dave1814 (Jan 5, 2017)

So, just an update on this one! 

I got a local auto electrician to come and have a quick look at the car. He said basically the problem could be anywhere from the instrument cluster to the wiring through the dash and the engine. He suggested wiggling the wires and see when the temp reading starts to go crazy (as the fault is intermittent, and ive noticed it go funny when going over bumps).

What i've done is hooked up VCDS, ran the advanced measuring blocks for the ambient temperature and started wiggling all the wires from the sensor up to around the battery area. What I did notice is that the temp starts to drop when I shut the bonnet!

It turns out when I hit the top of the dash above the instrument cluster I get a drop in temp, so i'm thinking either the connection to the instrument cluster is dodgy, dodgy wiring behind the cluster or a fault cluster??

I plan to take out the cluster at the weekend, any other ideas before I do?

thanks!
Dave


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