View Full Version : Air conditioning unit on an Audi A4 2005

01-07-2014, 10:52 AM
Have an Audi A4 2005, had to change suction pipe. Pressure tested system, evacuated, and charged in 400 grams of 134a gas.

When I turned on system it did not run, I know we should have a charge of 550 grams.

Why will in not run, all help appreciated


Rob White
01-07-2014, 11:15 AM

Two reasons I can think of.

1 - there is not enough pressure to activate the LP switch.
2 - the climate control is not set low enough to call for cooling or is faulty.



02-07-2014, 10:46 AM
You should connect suitable diagnostic exuipment and check stored faults.

charlie patt
03-07-2014, 09:19 PM
1/ its a clutchless comp so centre of pump will spin all the time even when empty/ 2 if ac/econ light not flashing it has no digital codes up so scanner wont help/ 3 if you charged it as liquid and fired it right up the swash plate will be smashed up 4/ fit ur gauges u need standing pressure of at least 80 psi at 18 dc ambient run unit with ac on if the centre bolt/screw not spinning on comp the swash plate is smashed up if its spinning you need a coolguard tester to test comp as they run a basic sol valve system on back of pump if ac/econ light flashes it is picking up a fault on pressure switch ie pressure or condensor fan lockout audi vw sytems are crap full stop following faults are commom compressor condensor leak trianary switch rh condensor fan apart from that great ac

20-07-2014, 01:37 AM
You should connect suitable diagnostic exuipment and check stored faults.

vw/audi and some others with the clutchless compressor put a fault code on the ecu when the gas runs out...after recharging the system you need to erase the fault code before the system will run.