Fault Code Guide

Wake Circuits Troubleshooting Procedures
Test
No.
Test Procedure Test Result Action
2 If everything works correctly after meeting the conditions in
test no. 1, the system should go to sleep within 60 seconds.
The template indicates this when all of the annunciators show
an exclamation mark (!)
*
.
NOTE: If the vehicle has one of the following reference
parameters, the system will remain awake for 24 hours or
longer: 26-01017-002, 26-01019-003, 26-01019-004, or 26-
01019-005.
NOTE: This troubleshooting step describes a special
circumstance that is not typical of the majority of vehicles.
If the system is not working correctly, one or more of the
Wake Circuits in the right column of the "Wake Function"
Datalink Monitor template remains active (yellow) after 60
seconds.
Within 60 seconds of meeting the conditions in test no. 1, do
all of the annunciators on the template show an exclamation
mark (!)
*
?
Yes
Go to test no. 6.
No
Go to test no. 3.
3 In the second column of the template under "Other Module
Wake Circuits–Status" is the status of all the annunciators
"LOW-Wake" (yellow)?
NOTE: Disregard the annunciators for modules not on the
vehicle; these will show an exclamation mark (!)
*
.
Yes
Check the wake circuits between the
BHM and the following modules for a
short to ground:
• CHM
• EXM
• SEM
Repair as necessary.
No Go to test no. 4.
4 If the B5.D BHM to ICU annunciator status is "ON" in the sec-
ond column of the template under "BHM Wake Circuits–
Status," continue with this test. If not, go to test no. 5.
Disconnect BHM connector B5.
Test for voltage on pin B5.D (harness side).
Is voltage present?
Yes
The wake circuit between the BHM
and ICU is shorted to power.
Repair as necessary.
No
Go to test no. 5.
5 In the second column of the template under "BHM Wake
Circuits–Status," check the status of the annunciator labeled
B1.B BHM to CHM
B4.H BHM to EXM
B6.A2 BHM to SEM.
Is the annunciator status "LOW-Wake" (yellow)?
Yes
If this is the only active annunciator,
replace the BHM.
No
Check the multiplexed modules for
ignition circuits that are shorted to
power (not powering down when the
ignition is off). If no problem is found,
the system may not be going to sleep
because the BHM is not sending the
J1939 go-to-sleep message. Try a
test BHM to confirm.
Bulkhead Module 54.12
Troubleshooting
Business Class M2 Workshop Manual, Supplement 22, September 2012300/16