A/C - Won't Cool
87 Air conditioning does not cool87 10 02
2016496/4
June 8, 2010
Supersedes Technical Service Bulletin Group 87 number 09-06 dated November 20, 2009 for reasons listed below.
Affected Vehicles
Condition
^ Air conditioning does not cool. This symptom can be intermittent.
^ The LED in the ECON button of the AC control panel comes on intermittently.
^ The functionality of the HVAC blower is unaffected by this condition.
Technical Background
Refrigerant leak from the high pressure sensor G65. As the system leak causes the volume of available refrigerant to decrease, the correct operation of the air conditioning system can be intermittent.
-or-
The high pressure sensor G65 malfunctions and sends implausible values to the control head J255. The air conditioning system then shuts down the compressor.
Production Solution
Introduced a new supplier, Sensata, with an improved high pressure sensor G65.
Service
1. Recover the refrigerant from the system and measure the volume.
Make careful note of the amount of PAG oil recovered. This amount will need to be added when the system is recharged. If the recovered volume is less than 350 g, there likely is a system leak.
2. Check for refrigerant loss at the high pressure sensor G65 with an electronic leak detector or leak detection dye. If the sensor is the source of the leak, inspect for PAG oil residue in and around the sensor and electrical connector.
3. If only a small amount of oil is found, the refrigerant system will not have to be flushed. Clean the electrical contacts of the sensor plug.
4. If a substantial amount of refrigerant oil residue is found, the total system volume of refrigerant oil will have to be reestablished when the system is recharged after repairs are complete. If this is not done, air conditioning compressor failure will occur.
5. If the refrigerant system has lost a substantial amount of oil and it becomes necessary to correct the system volume of PAG oil:
a. Flush the refrigerant circuit according to the repair information in ElsaWeb.
b. Drain the air conditioning compressor.
c. Replace the receiver drier.
d. Fill the system with the necessary oil quantity as specified in ElsaWeb.
6. If the high pressure sensor G65 is not the source of the leak, perform a system leak test with an electronic leak detector or leak detection dye. Repair the leak as necessary.
Tip: If there is debris in the system, it must be flushed out and the compressor, receiver drier and expansion valve must be replaced. Make certain that a complete system charge of refrigerant oil is included in the new compressor. Adjust volume if necessary.
7. After replacing a leaking high pressure sensor G65 and all other repairs are complete, check the cooling performance according to the repair information in ElsaWeb.
8. If there is no system leak whatsoever and the correct volume of refrigerant is in the system, proceed with Step 9.
9. Check fault memory in address word 08 A/C / Heating Electronics. If a fault is stored in control head J255, perform the Guided Fault Finding test plan as specified.
10. If no fault is stored, ensure the engine is off and the key is in the on position. Then read measuring value block 1, field 4 in address word 08 A/C / Heating Electronics.
11. Allow the refrigerant in the system to equalize for approximately 60 seconds. If the pressure value fluctuates abruptly or is implausible, replace the high pressure sensor G65.
Tip: Remember that at 20°C ambient temperature, the pressure value should be approximately 5 bar.
Warranty
Required Parts and Tools
Additional Information
All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service manuals for the latest information.