Hi Guys,

I have a  Focus 2014 (mk3) 1.5L Duratorq-TDCi which has just gone out of warranty.

When I turn the air conditioning on (any settings, even max a/c) I get warm air.

I've used forscan to check for DTC (diagnostic trouble codes) on the HS (OBD) and MS (ford) bus with no helpful results.

Running a self test (key on engine off) of the PCM (powertrain control module) on the HS bus does successfully pull in the A/C clutch and does not report any faults. When the clutch is pulled in, it is solid and can't be turned. So the clutch itself appears to be fine.

Running a self test of the HVAC module on the MS bus passes.

I've monitored the following PIDs

ACP_V - A/C pressure sensor voltage - 0.55 volts. Shop manual says the sensor should be between 0.3-4.7 volts

INCARTMP - In car temperature - 215 degC. I have seen one reference online to 215degC being a "dummy" value on some cars, so perhaps normal.

AC_REQ - Air conditioning request signal - "Yes" (when engine is running and A/C button is pressed)

CACRP - Corrected air conditioning refrigerant pressure - 125.0kPa (compressor not running for this reading, obviously).

The shop manual says for the mechanic to check the A/C system pressure via a manifold gauge set with the engine OFF. It should be above 290kPa. It then goes on to say this should be "similar" to the ACP_PRESS PID (which I think is the CACRP from forscan).

I'm going to have the system recharged tomorrow, hopefully that fixes the problem.

 

For reference, there is an evaporator temperature sensor, which is supposed to detect and cut the A/C off if it thinks the evaporator is icing up. I believe this is located in the passenger footwell, on the side of the HVAC box, with a 3 pin black connector going into a blue socket. I don't believe this can be monitored as a PID. The resistance of this can be checked as follows:

0degC = around 100kohms, 25degC = around 30kohms, 60degC = around 8kohms. I'm yet to check this.

 

Let me know if anyone else has any other faultfinding tips, and maybe someone else will find this useful.

 

If the system is low on gas/pressure then the a/c clutch won’t operate. 

You are quite right!

The recharge has got it running again 

Now I'm reading about 1400kPa when the engine is running, and 700kPa when the engine is off (it was a very hot day).

Hello

I have Focus MK3 2014 year 2.0 L 163KM . Car was in 2 workshops with no results .  I have problem with doesnt working AC . I checked and recharged refrigerant , but clutch doesnt engaged . I have no stering signal on Relay R11. Could you send me manuals witch did you used to cheking your AC . Maybe i find information about relation between pressure and voltage on pressure sensor , and others sensors like inside temperature , evaporator , sun etc.

 

Best regards

my email [email protected]

My focus is In the garage just now and the guy said they can’t recharge the air con as my pipes have connections their machine dosnt fit  surely it’s a bog  standard size 

20 minutes ago, Wee joe said:

My focus is In the garage just now and the guy said they can’t recharge the air con as my pipes have connections their machine dosnt fit  surely it’s a bog  standard size 

There are 2 x different A/C connectors, one (R134A) gas for cars roughly prior to 2015, and the newer 'environmentally friendly', and 3 times more expensive gas for cars built after 2015 (R1234yf). Sounds like your guys can't service older cars which is very unusual for anyone in the car A/C business.