A/C - Blower Motor Operates at Reduced Speeds
SI B 64 22 05Heating and Air Conditioning System
December 2005
Technical Service
This Service Information bulletin supersedes S.M. B64 205 04 dated August 2004.
SUBJECT
Blower Motor Operates at Reduced Speed
MODEL
E65, E66 (7 Series)
SITUATION
The customer states that after the vehicle is started the blower motor operates at a reduced speed, especially when "MAX" A/C is selected.
CAUSE
The Power Module activates the "Load-circuit peak reduction" function based on battery SoC (State of Charge), thus reducing the blower speed output.
Since September 2003 the message in the Control Display "A/C System Restricted" is suppressed. This includes vehicles that have had the software updated using CIP 9.4 or later.
PROCEDURE
1. Duplicate the customer complaint.
2. Perform a short test on the vehicle and complete all DIS test plans (including "Energy Diagnosis" if applicable) on any relevant faults.
3. Select "Control module functions" and select "PM Power Module" from the control modules list.
4. Select "Diagnosis requests" and "-Load/consumer priorities".
5. Select "Load/consumer priority A+B" and "Display".
6. Note the number in the "Messages and results" screen.
^ 0 = Normal operation without peak reduction (KL 15 "ON")
^ 1 = Terminal R "ON" without peak reduction or generator defect or undervoltage acknowledged.
^ 4 = Corresponds to maximum peak reduction.
^ 5 = Corresponds to medium peak reduction.
^ 6 = Corresponds to minimum peak reduction.
7. Refer to the "Table of priorities" shown for further information.
8. If peak reduction has been confirmed, check the battery and charging system using the BMW Battery Tester. Refer to S.I. B04 25 02.
9. Check for excessive closed-circuit current using the 50-Amp clamp as outlined in S.I. B61 08 00.
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