Suzuki XL7 2007 Service Manual page 2250

9A-142 Wiring Systems:
Circuit/System Description
This vehicles power mode master (PMM) is the body
control module (BCM). The ignition switch is a low
current switch with multiple discrete ignition switch
signals to the PMM for determination of the power mode.
The PMM receives the ignition switch signals, and
additionally a reference voltage signal from the BCM,
through the ignition switch, and back to the BCM. There
are redundancies within the PMM system that can allow
operation of certain subsystems when there are faults in
the ignition switch circuits. Other information such as
serial data input from other modules and DTCs is also
used to determine what power mode signals and
information is transmitted by the PMM. The BCM logic
uses all this information to identify the operators desired
power mode and activate specific discrete signals, and
serial data messages for the operation of many different
subsystems as necessary. Other modules which have
switched voltage inputs may operate in a default mode if
the PMM serial data message does not match what the
individual module can see from its own connections.
The PMM will activate relays and other direct outputs of
the PMM as needed according to the calculated power
mode. Several relays controlled by the BCM are
switched ignition voltage outputs the are pass through
circuits within the BCM directly from the ignition switch. If
these circuits short to ground, the fuse to the ignition
switch will open.
Some system functions may operate one time and not
the next with a specific fault in the ignition switch circuits
depending on the vehicle operating conditions when the
fault occurred. Some examples are as follows:
Vehicle Conditions
• Vehicle running or not running
• Multiple circuit faults
• Ignition key position
• Transmission gear selected
System Action
• The vehicle may or may not start
• Instrument panel indicators may illuminate or not
illuminate at inappropriate times
• Remote start may operate incorrectly
• Ignition key may not return to OFF
• Specific Retained Accessory Power (RAP) functions
may operate while others do not
Conditions for Running the DTC
B1380 01
Ignition switch is in the START position.
B1380 06
Ignition switch is in the RUN position.
Conditions for Setting the DTC
B1380 01
Accessory voltage circuit is shorted to voltage for more
than 2 seconds.
B1380 06
• Accessory voltage circuit is open for more than 2
seconds.
• Ignition 1 voltage, accessory voltage, or off/run/crank
voltage circuit shorted to ground.
• Battery positive voltage circuit of the ignition switch
open or shorted to ground.
Conditions for Clearing the DTC
• A current DTC clears when the malfunction is no
longer present.
• A history DTC clears when the module ignition cycle
counter reaches the reset threshold, without a repeat
of the malfunction.
Diagnostic Aids
• A short to ground in the accessory voltage circuit will
cause an open fuse to the ignition switch. DTC U1814
should be current.
• A short to ground in the ignition 1 voltage circuit of the
ignition main relay 31 will cause an open fuse to the
ignition switch. DTC B1428 should be current.
• The power modes and controls are determined using
BCM logic. Comparing the Body Control Module
Power Mode data display parameters listed in Circuit/
System Verification will determine if there is a power
mode fault.
Reference Information
Schematic Reference
• "Power Moding Schematics"
• "Power Distribution Schematics"
Connector End View Reference
"Power and Grounding Connector End Views"
Electrical Information Reference
• "Circuit Testing"
• "Connector Repairs: "
• "Testing for Intermittent Conditions and Poor
Connections"
• "Wiring Repairs"
Scan Tool Reference
• "Scan Tool Data List - Wiring Systems and Power
Management"
• "Scan Tool Data Definitions - Wiring Systems and
Power Management"