Suzuki XL7 2007 Service Manual page 209

Diagnostic Aids
• Inspect the KS for physical damage. A KS that is
dropped or damaged may cause a DTC to set.
• Inspect the KS for proper installation. A KS that is
loose or over torqued may cause a DTC to set. The
KS should be free of thread sealant. The KS mounting
surface should be free of burrs, casting flash, and
foreign material.
• The KS must be clear of hoses, brackets, and engine
electrical wiring.
• The normal voltage on the KS signal and low
reference circuits is 2.43 volts when the KS is
disconnected.
• A short to voltage on a signal or low reference circuit
will cause a KS DTC to set for both banks of the
engine.
Reference Information
Schematic Reference
"Engine Controls Schematics"
Connector End View Reference
• "Engine Control Module Connector End Views"
• "Engine Controls Connector End Views"
Description and Operation
"Knock Sensor (KS) System Description: "
Electrical Information Reference
• "Circuit Testing: "
• "Connector Repairs: "
• "Testing for Intermittent Conditions and Poor
Connections: "
• "Wiring Repairs: "
DTC Type Reference
"Powertrain Diagnostic Trouble Code (DTC) Type
Definitions"
Scan Tool Reference
• "Scan Tool Data List - Engine Controls - 3.6L (LY7)"
• "Scan Tool Data Definitions - Engine Controls - 3.6L
(LY7)"
• "Scan Tool Output Controls - Engine Controls - 3.6L
(LY7)"
Circuit/System Verification
1. Engine at operating temperature, all accessories
OFF. Engine speed greater than 2,000 RPM,
observe the appropriate KS signal voltage parameter
with a scan tool. The voltage should be greater than
2 volts.
2. Engine idling, move the related harnesses and
connectors for the KS circuits while observing the KS
signal voltage parameters with a scan tool. The
voltage should remain steady with no abrupt
changes.
Engine General Information and Diagnosis:
3. If the vehicle passes the Circuit/System Verification
test, then operate the vehicle within the conditions
for running the DTC. You may also operate the
vehicle within the conditions that are captured in the
Freeze Frame/Failure Records List.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at
the appropriate KS.
NOTE
If the voltage is not within the specified range
on either circuit, test for a wire to wire short,
short to ground or voltage between the KS
circuits.
2. Ignition ON, test for 2-3 volts between the signal
circuit terminal 1 and ground.
➢ If less than the specified range, test the signal
circuit for a short to ground or an open/high
resistance. If the circuits/connections test normal,
replace the ECM.
➢ If greater than the specified range, test the signal
circuit for a short to voltage. If the circuits/
connections test normal, replace the ECM.
3. Test for 2-3 volts between the low reference circuit
terminal 2 and ground.
➢ If less than the specified range, test the low
reference circuit for a short to ground or an open/
high resistance. If the circuits/connections test
normal, replace the ECM.
➢ If greater than the specified range, test the low
reference circuit for a short to voltage. If the circuits/
connections test normal, replace the ECM.
4. If all circuits/connections test normal, test or replace
the KS sensor.
Component Testing
1. Connect a DMM set to the AC mV scale, between
the terminals of the KS.
2. Tap on the engine block with a non-metallic object
near the KS while observing the DMM.
3. The DMM should display a fluctuating AC voltage
greater than 30 mV while tapping on the engine
block.
➢ If less than the specified valve, replace the KS.
Repair Instructions
Perform the "Diagnostic Repair Verification - Vehicle
Diagnostic Information: " after completing the diagnostic
procedure.
• "Knock Sensor Replacement - Bank 1: "
• "Knock Sensor Replacement - Bank 2: "
• "Control Module References: " for engine control
module replacement, setup, and programming
1A-104