Problems with air compressor replacement

05/02/2022

INTRO

When the air compressor is changed on Teslas, things normally goes quite smoothly. But a number of difficulties can also arise. You may get problems with pressure in the tank (especially S pre-facelift), or the compressor does not fill up the air struts. That it simply does not start is not an unknown phenomenon either. 


You can read more about pressure challenges here, under the heading 'Air Pressure' a bit down at the page, and in point III below. When problems arise, it is often the electronics that 'read' the new situation incorrectly. This is not so easy to correct without Tesla's toolbox and software. But some suggested solutions follow below. This requires both that the fuse and relay have been checked, and that the new compressor works as it should.


DISCLAIMER

Teslasuspension.com is not responsible in any way for actions you take as a result of this text. Work on all types of air pressure systems requires caution and that you familiarize yourself with the car manufacturer's instructions. Always also follow standard safety instructions for working on a car. 


I. COMPRESSOR STARTS AND SWITCHES OFF/ON. EVERYTHING SOUNDS FINE, BUT AIR IS NOT PUMPED TO THE BELLOWS 

  1. Indication. The level sensors on each axle have 'locked' and need a reset. 
  2. There are indications that changing the wheel position on the screen (to 21" or 19", whichever), and back, 'tricks' the car, and the sensors start again. 
  3. Besides on/off with relay and fuse (the latter most relevant for X and S facelift and pre-face from Sept. 2015), also try options II and IV below.


II. COMPRESSOR STARTS BUT IT JUST RUNS CONSTANTLY WITH NO EFFECT. HEIGHT ADJUSTMENT GIVES NO RESPONSE 

  1. Indication. The ECU (electronic control unit) needs a reset 
  2. Much indicates that a simple restart of the screen using the scroll wheels on the steering wheel will help (that the ecu also gets a new boot). 
  3. Besides on/off with relay and fuse (the latter most relevant for X and S facelift and pre-face from Sept. 2015), also try option I and IV above/below.


III. COMPRESSOR STARTS AND FILLS THE AIR SUSPENSIONS TO 'VERY HIGH' BUT AIR DOESN'T GO OUT OF THEM AGAIN. THE AIR STRUTS ARE 'STUCK' IN THE GIVEN POSITION 

  1. Indication. Electronic reading incorrect, or valve block problems (or possibly compressor) 
  2. First, check that all steps in points I, II and IV above/below have been carried out 
  3. For pre-facelift S models, be sure that the residual pressure valves on the air struts are not cheap Asian copies. These are unstable and can lock the bellows in a 'very high' position. 
  4. We also assume that there is nothing wrong with the level sensors at each axel, or the new compressor.  There are 2 solenoids or return valves in the compressor, and one controls the pressure in the tank. If this fails, air will not return to the tank. 
  5. We are then left with a valve block. Things may indicate that a venting through this can clear up the situation. You may try the following: 
  • The air struts are accordingly stuck in a 'very high' position with approx. 9 bars individually. The pressure in the tank is also then around 9 bar. 

  • Manually fill up the pressure in the tank a couple of bars, to approx. 11. The car's compressor, of course, is off. You then create an overpressure in the system. 

  • Start the car and adjust to 'high'. If things go as they should, the system dumps air/overpressure immediately. This happens by blowing it out through the exhaust outlet on the valve block, and you should hear a strong 'wooooooosh'. 

  • The exhaust possibly dissolves something on the valve block. Or, there is something about the electronics that kicks in, and things are brought to life. 

  • Whatever happens, many people have gotten their air struts out of a 'stuck' position this way. Similar, if not the same method, can probably have an equal effect 


IV. COMPRESSOR DOES NOT START OR THE AIR SUSPENSION DOES NOT EXIT SERVICE MODE 

  1. Indication. The entire electronic system needs a reset. 
  2. First, check that steps I and II above have been completed. Also make sure all doors are closed. Compressor does not start, if e.g. the tailgate is open. Also try turning the car off, wait a bit, open the door to start the car. drive forward a little, and wait further. Or take a walk and let the car switch off. If you're lucky, service mode can be switched off when you're back, and the compressor starts. But if you don't get a response after repeated attempts, you must proceed more thoroughly. 
  3. Go to 'Security' in the screen, and switch off the car through the side window. 
  4. Disconnect the 'First responder' loop under the hood/top cover, see yellow arrow image. Wait at least 2 minutes until all electrical circuits are fully discharged.

5. Disconnect the 12v battery (minus pole first) 

6. Wait approx. 20 min 

7. Connect in the opposite direction 

8. Start up 

9. Then the compressor usually starts 


CONCLUDING REMARKS

These are just some suggestions on how to solve problems that may arise when installing an air compressor. There are certainly other methods, which may also work better. If you have any tips in that direction, feel free to drop us a line at post@teslasuspension.com