Suzuki XL7 2007 Service Manual page 276

1A-171 Engine General Information and Diagnosis:
Reference Information
Schematic Reference
"Engine Controls Schematics"
Connector End View Reference
• "Engine Control Module Connector End Views"
• "Engine Controls Connector End Views"
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. Ignition ON, observe the DTC information with a
scan tool. Verify that DTCs P0137, P0138, P0140,
P0157, P0158, or P0160 are not set.
➢ If any of the listed DTCs are set, refer to
"Diagnostic Trouble Code (DTC) List - Vehicle
Diagnostic Information: " for further diagnosis.
2. Operate the engine above 1,200 RPM for 30
seconds, observe the HO2S voltage parameter. The
reading should fluctuate above and below the range
of 350-550 mV.
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 Data List.
Circuit/System Testing
1. Engine operating, move the related HO2S
harnesses for the appropriate rear sensor between
the HO2S harness connector and the engine control
module (ECM) while monitoring the appropriate
HO2S voltage parameter. Verify that the HO2S
parameter does not change abruptly while moving
the related harnesses.
➢ If the HO2S parameter does change abruptly while
moving the related harnesses repair the circuit as
necessary.
2. Ignition OFF, disconnect the harness connector of
the appropriate HO2S.
3. Ignition ON, verify that the HO2S parameter is
between 350-500 mV.
➢ If more than 500 mV, test the signal circuit of the
HO2S sensor for a short to voltage. If the circuit/
connections test normal, replace the ECM.
4. Verify that none of the following conditions exist:
– Rich fuel injectors—Refer to "Fuel Injector
Balance Test with Special Tool: " or "Fuel Injector
Balance Test with Tech 2: ".
– Water intrusion in the HO2S harness connector
– High fuel system pressure—Refer to "Fuel System
Diagnosis: ".
– Fuel that is contaminated—Refer to "Alcohol/
Contaminants-in-Fuel Diagnosis (w/o Special
Tool): " "Alcohol/Contaminants-in-Fuel Diagnosis
(w/ Special Tool): ".
– A collapsed air intake duct
– A restricted air filter element
– Exhaust system restrictions
– Excessive fuel in the crankcase
– An engine mechanical condition—Refer to
"Symptoms - Engine Mechanical: ".
➢ If you find any of the above conditions, repair as
necessary.
5. If all circuits/connections test normal, replace the
applicable HO2S.
Repair Instructions
Perform the "Diagnostic Repair Verification - Vehicle
Diagnostic Information: " after completing the diagnostic
procedure.
• "Heated Oxygen Sensor Replacement - Bank 1
Sensor 2: "
• "Heated Oxygen Sensor Replacement - Bank 2
Sensor 2: "
• "Control Module References: " for engine control
module replacement, setup, and programming