Suzuki XL7 2007 Service Manual page 918

1J-25 Charging System:
Circuit/System Description
The engine control module (ECM) uses the generator
field duty cycle signal circuit to monitor the duty cycle of
the generator and fault indication. The generator field
duty cycle signal circuit connects to the high side of the
field winding in the generator. A pulse width modulated
(PWM) high side driver in the voltage regulator turns the
field winding ON and OFF. The ECM uses the PWM
signal input to determine the generator load on the
engine. This allows the ECM to adjust the idle speed to
compensate for high electrical loads.
The ECM monitors the state of the generator field duty
cycle signal circuit. When the engine is running, the
ECM should detect a duty cycle that varies up to 100
percent. The ECM monitors the PWM signal using a key
ON test and a RUN test. During the tests, if the ECM
detects an out of range PWM signal, a DTC will set.
Conditions for Running the DTC
• The vehicle speed is above 8 km/h (5 mph).
• The engine speed is less than 3,000 RPM.
Conditions for Setting the DTC
The ECM detects a pulse width modulated (PWM) signal
less than 5 percent for at least 15 seconds.
Action Taken When the DTC Sets
• The ECM will command the charge indicator and or
warning message to be illuminated on the instrument
panel cluster (IPC) and the driver information center
(DIC), if equipped.
• The ECM will not illuminate the malfunction indicator
lamp (MIL).
• The ECM will store conditions, which were present
when the DTC set as Failure Records data only.
Conditions for Clearing the DTC
• The ECM will command the message OFF after one
trip in which the diagnostic test has been run and
passed.
• The history DTC will clear after 40 consecutive warm-
up cycles have occurred without a malfunction.
Reference Information
Schematic Reference
"Starting and Charging Schematics: "
Connector End View Reference
"Engine Electrical Connector End Views: "
Description and Operation
"Charging System Description and Operation"
Electrical Information Reference
• "Circuit Testing: "
• "Connector Repairs: "
• "Testing for Intermittent Conditions and Poor
Connections: "
• "Wiring Repairs: "
Scan Tool Reference
• "Scan Tool Data List - Engine Electrical: "
• "Scan Tool Data Definitions - Engine Controls - 3.6L
(LY7): "
Circuit/System Verification
Engine running, observe the scan tool GEN-F Terminal
Signal parameter. The GEN-F Terminal Signal
parameter should read between 5-95 percent.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at
the generator.
2. Ignition ON, engine OFF, observe the scan tool
GEN-F Terminal Signal parameter, while repeatedly
probing the generator field duty cycle circuit with a
test lamp connected to battery positive voltage. The
parameter should change from 0 percent to above
95 percent.
➢ If the parameter was not affected by the test lamp,
test the circuit for a short to ground or an open/high
resistance. If the circuit tests normal, replace the
ECM.
3.
If the circuit tested normal and the ECM parameter
changed from 0 percent to above 95 percent,
replace the generator.
Repair Instructions
Perform the "Diagnostic Repair Verification - Vehicle
Diagnostic Information: " after completing the diagnostic
procedure.
"Control Module References: " for ECM replacement,
setup, and programming
"Generator Replacement" for generator replacement.