Wednesday, November 23, 2011

How to replace the G62 Coolant Sensor on a 2006 VW Passat 2.0T

VW Passat G62 Coolant Sensor.

The CEL (Check Engine LIght) came ON and after scanning the car with VAG-COM by Ross-Tech, the report displayed the following fault code:

008577 - Performance Malfunction in Cooling System
P2181 - 008 - Implausible Signal - MIL ON
Freeze Frame:
Fault Status: 11101000
Fault Priority: 0
Fault Frequency: 2
Mileage: 84971 km
Time Indication: 0
Date: 2011.09.24
Time: 16:47:51

Freeze Frame:
RPM: 1491 /min
Load: 27.4 %
Speed: 52.0 km/h
Temperature: 74.0°C
Temperature: 42.0°C
Absolute Pres.: 1000.0 mbar
Voltage: 14.097 V

This fault code could result from various causes. These causes could range from a faulty thermostat, G62 Coolant Sensor, radiator fan, or even a discrepancy in the antifreeze concentration. In my case, it was a faulty G62 Sensor.


First of all, the G62 Coolant Sensor is located on the right side of the engine at about mid level. It is a black plug in the middle of the image below with a green and brown wire attached to it.

This is a close up of the G62 Coolant Sensor Plug.


Remove the black G62 Coolant Sensor plug. After that, you must remove the fastening clip in the 2nd image below. This clip slides into a groove that is perpendicular to the G62 Coolant Sensor, and holds it in place. It prevents the G62 Coolant Sensor from popping out and leaking all the antifreeze. You can see the groove in the 1st picture below, on the top part of the black part where the sensor plugs into.


Now, there is an easy way to replace the G62 Coolant Sensor without flushing out all the antifreeze. You put a few folded towels under the sensor, pull out the old sensor and insert the new G62 Coolant Sensor. Before doing this, make sure that the new sensor is ready with a new O Ring on it. When you pull the old sensor out, antifreeze is going to start leaking out, but it only takes a few seconds to plug in the new sensor and stop the leak. ***One problem that might arise when you pull out the old G62 Coolant Sensor is that the O ring may slide off the sensor, so you have to stick your finger in the opening and pull it out.*** So make sure that the engine is cold so you don't burn yourself with hot antifreeze.***


After inserting the new G62 Coolant Sensor, place the fastening clip into its groove and make sure the sensor can't be pulled out. Then insert the plug back into the G62 Coolant sensor until it clicks into a fastened position.

Step 5

Finally, check the level of antifreeze and add coolant accordingly to adjust for the loss during the replacement of the G62 Coolant Sensor. Scan the car with VAG-COM again and clear the fault code. Then start the engine and check for any leaks.


  1. Nice article, how did you manage to ascertain that it was the sensor and nothing else? I have almost exactly the same error but would really like to know before the garage gets a look!

    008577 - Performance Malfunction in Cooling System
    P2181 - 008 - Implausible Signal - Intermittent - MIL ON
    Freeze Frame:
    Fault Status: 10101000
    Fault Priority: 0
    Fault Frequency: 13

    1. This fault code can be due to several reasons (G62 Sensor,Coolant Mixture Concentration "should be 50/50",Thermostat,or Radiator Fans). When you take it to the garage, they trouble shoot it from the cheapest fix to the more expensive. The code does not pinpoint the exact error. In my case it was the sensor, and there are 2 G62 sensors, the one shown above and another in the Hose coming down from the thermostat, which is located in the front of the engine to the right of the alternator.

  2. Are any of the reasons likely to be highly problematic? Deciding whether or not a 400 mile round trip with the orange light on is the best thing to do right now.

    1. The main thing to pay attention to is the engine temperature. I ran mine for months with the CEL light on. If the fans are working, and the thermostat is opening to recirculate the coolant fluid, it should be fine. Then again use your best judgement. Main problem is overheating the engine. If the engine temp is normal, it should be fine.

    2. I got round to this a while back and have been engine light free since. This was a very straightforward bit of maintenance that I would recommend even the most fearful could attempt.

      Thanks for posting, has been very useful!

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