Reduced Engine and Air-Conditioning Performance. When driving with high outside ambient temperatures, repeated stop and go, or high load operation over longer distances, the engine performance can be reduced. The air-conditioning system blower output may also be reduced, and in some circumstances the compressor is switched off. There could be any of the following faults stored depending on the conditions present at the time. DME * Fault 1A2108: Electric fan, self-diagnosis, interval stage 1: Minor fan fault EGS (also possibly set) * Fault 421722: DME/DDE interface: Forced upshift due to thermal engine protection request IHKA (possibly set without DME or EGS faults) * Fault 801224: Air conditioning compressor: Shut-down due to excess pressure in refrigerant circuit * Fault 801228: Blower output stage: Blower output reduction due to power management The Service Engine Soon lamp (MIL) would not be illuminated in these situations. 1. A DME software error in the control of the 850W electric fan over-boost or high speed function. 2. The electric cooling fan design was not robust enough for continuous over-boost or high speed operation.