Hi all,

I have an issue with my HVAC system, and I'd appreciate some ideas on what to do next.

2011 L322 5.0 NA with a two-zone AC.
I have a GAP IID tool.


Problem history / background:
I'm located in the United Arab Emirates, where it’s quite hot outside (currently around 30°C at night and 40°C during the day).I bought the car a month ago, it's my first Land Rover.


During the pre-purchase inspection, I had two HVAC-related DTCs:
- B1087-54 - LIN bus A - System programming failure - missing calibration (2B)
- B11E3-87 - Rear heating ventilation air conditioning damper motor - Bus signal/message failure - missing a message (2B)
The seller also mentioned that sometimes there's no air from the front vents, but the rear vents always work.


On my first drives, I noticed that every time after 45-60 minutes, there was no more airflow from the front vents (though the rear vents worked, and the front blower became louder and louder in "Auto" mode without airflow). After stopping for 15-30 minutes, everything worked again until the issue reoccurred. I read that a wrong freon level might cause a freezing evaporator, so I had the AC freon evacuated and refilled to the correct amount (750 g for the 2-zone AC; only 600 g was in it previously).


Current problem situation:
After refilling the freon, my AC now cools excessively when the AC switch is on. It becomes very, very cold in the car, and the evaporator still seems to freeze, especially at higher speeds (but much later than before, and I never had the situation again that the air flow is stopping).
My issue now is that it is getting too cold in the car. Even with 27°C or 28°C as the target temperature, it feels like I need jackets in the car; the vent temperature sometimes goes as low as -1°C (measured with a food thermometer at the vents).
When I turn off the AC, the car quickly becomes too warm due to the high exterior temperatures.
My current workaround is to keep the AC off most of the time and switch it on for 3-5 seconds every 1-2 minutes.

Steps I have taken so far:
- Refreshed the freon as mentioned.
- Used my GAP IID tool to investigate the damper motor issue and calibration. However, it shows "N/A" for all actuator positions and CO2/NOx sensor values.
- Fixed the B11E3-87 issue: the rear HVAC damper motor cable was disconnected (fortunately, this motor was easy to access).
- Despite fixing the damper motor, the B1087-54 calibration issue persists. I contacted the GAP IID support team, who provided fantastic assistance. I attempted the HVAC calibration service, but it either runs indefinitely or throws error code E7. Patrick from GAP read my log files and said that the tool triggers the routine, but it gets no response from the ECU, even after trying two software builds.
- Patrick also provided an HVAC ECU software update, but the ECU version numbers remained unchanged after flashing the update.


tl;dr situation now:
Damper motor issue solved. The B1087-54 calibration issue remains, and calibration with the GAP tool fails. I assume this DTC is why it's getting too cold.


DTC details from the workshop manual:
B1087-54 - LIN bus A - System programming failure - missing calibration (2B)
Climate Control distribution flap actuator calibration routine has not been run successfully
Using the manufacturers approved diagnostic system, configure existing heating ventilation and air conditioning control module
Clear the DTC and retest
If the problem persists run, Actuator End Stop Detection routine

Other remarks and assumptions:
- I had access to another 2011 L322. There, also the GAP tool only shows "N/A" for the actuator positions and CO2 and NOX values, so I assume that it is unfortunately not able to read those values for the 2010-2012 L322 and the "N/A" problem is not related to my car / HVAC ECU.
- Sensor values for exterior and interior temperatures, as well as sun radiation, seem reasonable.
- The interior temperature sensor goes down to values way below the target (e.g., with 27°C or 28°C selected, it drops below 20°C), indicating the car knows it’s too cold but can't adjust.
- The HVAC (on "Auto" mode) is increasing the blower when I select 16°C as target temperature, compared to 28°C selected - so it definitely reacts to my input values.

Questions:
- Any ideas on what to try next?
- Is my assumption correct that an evaporator temperature around 2°C-4°C when stationary and as low as -3°C when driving over 100 km/h is too low?
- I’ve read that all airflow passes through the evaporator before being heated to the desired temperature. Could the heater be faulty, or does it anyways not operate at exterior temperatures of 30-40°C?

Hi all,

I still wasn't able to solve the issue and I'd still really appreciate it if someone can give me any input or thoughts on the questions.

Questions:
- Any ideas on what to try next?
- Is my assumption correct that an evaporator temperature around 2°C-4°C when stationary and as low as -3°C when driving over 100 km/h is too low?
- I’ve read that all airflow passes through the evaporator before being heated to the desired temperature. Could the heater be faulty, or does it anyways not operate at exterior temperatures of 30-40°C?

There must be a lot of HVAC places near you with temps like that, probably best to get a professional to check it over....  Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Do you have access to the WSM section on Climate Control - Control Components?

I'll have a better look at the WSM a little later.

Thanks for your replies!

@Graeme
Yes, I have access to this section of the workshop manual. Please let me know if you have any ideas.

@Haylands
The independent Land Rover workshops I contacted so far had no real idea what to do and recommended to disassemble half of the car (full dashboard removal to reach HVAC components), which is even with the lower labour costs here expensive and would probably leave me without the car for a while. I havn't checked with HVAC specialists yet because I assume it is more a Land Rover specific fault.

That does seem a lot to mess with from the LR specialist, might be worth trying an air con guy, nothing special about the JLR setup you have....  Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

All that I've spotted so far is that the coolant valves can be closed under ecu control, noting that the valves are normally closed.

When the output is excessively cold but not high ambient temperature, you could feel the temperature of the hoses after the valves to confirm that hot coolant is flowing through the valves, although maybe not a 100% valid test.

The valve in the compressor that controls the flow through the compressor that is known to become sticky usually causing a delayed start to cooling might be stuck causing full flow through the compressor all the time rather than only as required.