Fault Code Guide

Wake Circuits Troubleshooting Procedures
Test
No.
Test Procedure Test Result Action
6 Starting with the system in the sleep state, activate one of the
inputs that initiates a wake, such as opening the driver’s door.
If the system is functioning properly, all of the annunciators on
the template in the second column should be active (yellow)
for ECUs equipped on the vehicle as long as the input
remains active. For example, the door is open.
NOTE: If the vehicle is not equipped with an SEM or EXM, it
is normal for the status of these annunciators to be "!"
*
.
Are all of the appropriate second column annunciators active?
Yes
Go to test no. 8.
No
Go to test no. 7.
7 Which annunciator is not active? B5.D BHM to
ICU
Replace the BHM.
B1.B BHM to
CHM
B4.H BHM to
EXM
B6.A2 BHM
to SEM
Replace the BHM.
Any one of
the "Other
Module
Wake
Circuits–
Status" for
ECUs that
are on the
vehicle.
Check for an open in the wake circuit
between the BHM and the module
that is not showing active.
If OK, check power, ground, and the
J1939 datalink to the ECU that is not
responding.
8 Does the ICU wake up when the door is opened? This is
indicated by the odometer being displayed.
Yes No problem found.
No
Check the wake circuit between the
BHM and ICU for open.
If OK, check fuse 20 and VBAT2
power supply to BHM B4.G.
If OK, ICU may be faulty.
Repair as necessary.
*
The exclamation mark (!) will show on the versions of this template released with ServiceLink version 4.0 and higher. On templates released in ServiceLink
versions prior to 4.0, if the annunciator is flashing, the flashing takes precedence over the status that it is displaying.
Table 24, Wake Circuits Troubleshooting Procedures
Bulkhead Module 54.12
Troubleshooting
Business Class M2 Workshop Manual, Supplement 22, September 2012 300/17