Electronic Height Control - Lamp ON/No Codes Set
Group 37Special Suspension Systems
37 01 01
Woodcliff Lake, NJ
Service Engineering
March 2001
SUBJECT:
EHC Warning Illuminated, No Faults Stored
MODEL:
E39 Sport Wagon, X5 (Vehicles with single axle air suspension)
SITUATION 1:
The EHC warning stays illuminated after the ignition is turned on and the instrument cluster self check has been completed. The warning shows as a text message "AIR SUSP INACTIVE" in the high cluster, or a warning lamp in the low cluster. No faults are stored in the EHC control unit. The air suspension system continues to work normally.
SITUATION 2:
The EHC warning comes on while driving. LCM SW 41 / HW C1 is installed in the vehicle. No faults are stored in the EHC control unit. The air suspension system continues to work normally. Note that this fault applies only to vehicles with the high cluster (IKE)
Note:
Be aware that owners may miss when the actual warning was set, and complain that they notice it only when driving. In the majority of cases, the warning sets as in situation 1.
CAUSE 1:
For Situation 1, the EHC module fails to send "I'm OK" message to the Instrument Cluster when KL 15 is switched on.
CAUSE 2:
For Situation 2, hardware/software error in LCM SW 41 HW C1, manufactured by Reinshagen (P/N 61 35 8 386 209).
Note:
That the LCM problem can only affect vehicles with the high cluster (IKE). The LCM has nothing to do with the EHC warning on the low cluster. On the low cluster, the warning is signaled over the K-bus directly to the low cluster from the EHC.
CORRECTION 1:
For Situation 1, install a relay in the power supply to the EHC module wired through the relay's normally closed contacts, and actuate the relay with a KL5O signal. When the engine is cranked (KL50), this signal causes the relay to open. The interruption of power to the EHC module causes it to do an internal reset after KL50 is released and the relay contacts close. After resetting, the EHC module sends an "I'm OK" signal on the K-bus, and the instrument cluster warning goes out.
Install the relay as follows:
1. Locate the EHC module (The E39 EHC module is in an electrical box to the right of the spare wheel. The X5 EHC module is in a carrier under the spare wheel, and to the right of the battery)
2. Remove the lower section of steering column trim (refer to repair instruction 31 31 020).
3. Remove the instrument panel lower trim and pedal assembly trim (refer to repair instructions 51 45 180 and 51 45 185).
4 Adjust the steering column so that it is fully extended, and in a fully lowered position.
5. Disconnect the battery (refer to repair instruction 12 00...).
6. Disconnect the ignition switch plug connector X33.
7. Cut a sufficient length of 22 gauge wire to run from the ignition switch connector to the EHC module in the trunk.
8. For vehicles with M62 engine only
Using a Quick Connect (3) P/N 61 13 8 364 566, splice in the 22 gauge wire (4) to the SW/GE wire (2).
(The SW/GE wire from connector X33 (1) pin 8, provides the KL50 crank signal to the starter relay).
Reconnect the plug connector.
9. For vehicles with M52 or M54 engine only
Carefully spread out the clips (2) on both sides of connector X33 (1) and remove the anti-backout (3).
10. For vehicles with M52 or M54 engine only
Locate the GE/SW (X5) or SW (E39) wire to pin 8 of X33 (5). Using push-out tool 61 1 132 (found in Tool Kit 61 1 150), remove the terminal pin 8.
(The GE/SW (X5) or SW (E39) wire from X33 pin 8, provides the KL50 crank signal to the starter).
Cut off the terminal as close as possible to the terminal
Strip off the insulation from both the GE/SW or SW wire (1) and the 22 gauge wire (2) and splice them together by twisting together the conductors and crimping on a new terminal. (3) P/N 61 13 1 376 206. Double crimp (wire crimp and insulation crimp) the terminal using crimp tool P/N 81 24 9 408 126 (tool is marked Ampliversal 720781-3) found in the Electrical Repair Kit 1.
Reassemble the anti-backout (4).
Reconnect the plug connector.
11. Using plastic wire ties, route the new wire so that it follows the path of the main wiring harness to the front bulkhead, making sure it does not interfere with the telescoping steering mechanism.
12. At a convenient under dash location, cut the 22 gauge wire and install an in-line fuse holder (1) with 2.5A fuse.
To install the in-line fuse holder, strip off 3 mm insulation from each end of the 22 gauge wire. Using butt connectors / heatshrink (2) (from Electrical repair kit A P/N 61 9 051), double crimp (wire crimp and insulation crimp) the butt connectors using the Ampliversal crimp tool.
Use a heat gun to secure the heatshrink in place.
Use wire ties close to the inline fuse holder to hold it in place.
13. In order to run the new wire to the rear of the vehicle, remove the driver's side front and rear rocker panel strip (refer to repair instruction 51 47 000).
14. Remove the driver's seat (refer to repair instruction 52 14 000).
-- The battery will need to be temporarily reconnected in order to access the seat bolts.
-- There is no need to remove the seatbelt bolt from the seat frame. The seat can be positioned next to the vehicle with the seatbelt still attached).
15. Remove the lower B-pillar trim (refer to repair instruction 51 43 150)
16. Remove the driver's side kick panel (refer to repair instruction 51 43 070).
17. Lift up the rear seat cushion.
18. Route the new wire through the passenger compartment to the EHC module in the trunk, following the main battery cable (X5) or main harness (E39). Existing wire ties can be used to secure the new wire in position.
19. Remove the plug connector (1) from the EHC module. Cut a piece of 22 gauge wire approximately 12 in. long. (Preferably use a different color wire in order to distinguish the new wire (3) from the wire (5) run from the front of the vehicle.)
Locate the EHC ground wire (2) - BR/SW wire to pin 6
Using a Quick Connect (4) P/N 61 13 8 364 566, splice in the 22 gauge wire (3) to the BR/SW wire (2).
20. Cut two pieces of 18 gauge wire (4) and (6) (preferably different colors) approximately 12 in. long, and strip off 3mm insulation from each end.
The General Module provides the power supply to the EHC module. Locate the EHC power wire from the General Module (2) - RT/GE wire to pin 10, and cut it approximately 6 in. from the EHC plug connector (1). Strip off 3 mm insulation from the cut ends
Using butt connectors / heatshrink (3) and (5) (from Electrical repair kit A P/N 61 9 051), double crimp (wire crimp and insulation crimp) an 18 gauge wire to each end of the RT/GE wire using the Ampliversal crimp tool.
Use a heat gun to secure the heatshrink in place.
21. Cut the four new wires to an equal length, strip off approximately 3 mm insulation from each, and double crimp (wire crimp and insulation crimp) a terminal P/N 61 13 8 358 924 to each, using the Ampliversal crimp tool.
Assemble the terminals to the terminal base as follows:
Note:
- Remove the white anti-backout before terminal assembly, and reassemble after the terminals have been installed):
- Signal wire (1) (KL50) from the ignition switch, to relay terminal (85) Signal wire ground to EHC pin 6 (2), to relay terminal (86)
- Power wire from General Module (3), to relay terminal (30)
- Power wire to EHC pin 10 (4), to relay pin (87a)
22. Using electrical tape, tape the new wires to create a neat appearance.
23. Using plastic wire ties, mount the relay close to the EHC module.
24. Reinstall all removed components, and reconnect the battery.
25. With the relay installed, when the starter is cranked, the KL50 signal will cause the relay contact to open, causing a momentary interruption of power to the EHC module. This momentary interruption causes the EHC module to reset, after which it sends an "I'm OK" message over the k-bus, which then causes the EHC warning to go out.
CORRECTION 2:
For Situation 2:
Replace the LCM with LCM SW42. The LCM is located behind the passenger side kick panel (refer to repair instruction 51 43 075).
PARTS INFORMATION
WARRANTY INFORMATION
Covered under the terms of the BMW New Vehicle Limited Warranty.