Polo 6R - G65 sensor air conditioning pressure switch replacement

Post Instructions on DIY modifications here - use all information with caution!
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decvalts
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Drives: Polo 6R 1.2 TDI Bluemotion
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Polo 6R - G65 sensor air conditioning pressure switch replacement

Post by decvalts »

Problem:

Air conditioning unit only blows mildly cold air, or no cold air at all. Air con regas does not solve the problem. Scanning with a VCDS or generic fault code reader gives Fault Code 00819 - High pressure sensor Open circuit/short circuit to ground static.

Solution:

Replacement of the A/C High Pressure Sensor switch (G65 sensor/switch)

Difficulty: Not tricky technically, just awkward to get at and some of it has to be done by 'feel'.

The pressure sensor is located at the mid-front driver's side of the engine bay, in front and below of the coolant expansion tank. It is tricky to reach, but access can be made easier by removing the coolant expansion tank fixings and moving the tank to the side. (It does not need to be completely removed and drained.)

Moving the coolant expansion tank aside:

- Unclip the right side clip holding some hoses and push it aside.
- Remove the bolt and screw holding the tank to the chassis mounting point. (It appears it can be either a torx or a 10mm hex bolt. Mine was one of each!
- There is a large clip holding the tank in place, you need to reach under and push/wiggle it free to lift it up and out of the clip slot.
- Push the tank to the side as much as it will go without straining anything. The coolant sensor can be disconnected, although it may move far enough with this step.

Removing the old G65 sensor

- The A/C pressure sensor is a couple of inches long and screwed into one of the silvery metal pipes connecting the aircon system gas. A large stubby spanner or adjustable stubby wrench is needed to loosen the sensor. The stock sensor was about 24mm but replacements can vary. You want to loosen by the large central hex grip, not the smaller one close to the aircon pipe.
- You need to unclip the sensor connector wiring. This is tricky to do but can be made slightly easier by rotating the sensor slightly first so the clip release is pointing upwards where you can see it and unclip it by hand or with a flat head screwdriver.
- Once unclipped, continue to loosen the old sensor with the spanner or wrench. It will quickly become easier to unscrew by hand.
- If the aircon gas is correctly topped up/pressurised, you should hear a slight hiss when the valve is removed, but this should be brief and not drain the gas.

ImageImage

Replacing the new sensor.

- Attach the new sensor, an aftermarket replacement may not look identical but it should have the same thread and electrical connector at the respective ends.
- Finger tighten it, re-attach the sensor wiring connector, then tighten home with the spanner or wrench.

ImageImage

Reattach the coolant expansion tank and re-insert all hoses to their original positions.

Switch on the engine and aircon to test. Clear the fault code if you have a suitable fault code scanner. Rescan to check the fault code does not return.
shadowblue1
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Joined: Mon Sep 19, 2022 3:34 pm
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Re: Polo 6R - G65 sensor air conditioning pressure switch replacement

Post by shadowblue1 »

Is this the sensor , with the headlight removed?
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g65?
g65?
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iichel
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Re: Polo 6R - G65 sensor air conditioning pressure switch replacement

Post by iichel »

Yes, that's the high pressure sender for the AC circuit.
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