Suzuki XL7 2007 Service Manual page 266

1A-161 Engine General Information and Diagnosis:
Circuit/System Verification
1. If there are other DTCs set besides DTC P2177,
P2179, P2187, or P2189, refer to "Diagnostic
Trouble Code (DTC) List - Vehicle Diagnostic
Information: " to diagnosis the applicable DTC.
2. Ignition ON, observe the barometric pressure
(BARO) sensor pressure parameter and compare
the reading on the scan tool to the barometric
pressure table. Refer to "Altitude Versus Barometric
Pressure".
➢ If the BARO sensor pressure is not within the range
specified for your altitude, refer to "DTC P2227,
P2228, or P2229".
3. Engine at normal operating temperature, observe
the Total Fuel Trim Avg. parameter with a scan tool.
The Total Fuel Trim Avg. should be between −22 to
+23 percent.
Circuit/System Testing
1. Observe the LT FT Bn 1 and Bn 2 Cruise/Accel
parameters, in order to determine whether the lean
condition is effecting only one bank of the engine, or
is common to both banks of the engine.
➢ If the lean condition is common to both banks,
inspect for the following conditions:
– A mass air flow (MAF) sensor signal that is
skewed—If the Short Term FT parameters for both
banks changes more than 20 percent when the
MAF sensor is disconnected, refer to "DTC
P0101".
– The air intake system after the MAF sensor for
vacuum leaks
– Fuel contamination—Refer to "Alcohol/
Contaminants-in-Fuel Diagnosis (w/o Special
Tool): " "Alcohol/Contaminants-in-Fuel Diagnosis
(w/ Special Tool): ".
– Splits, kinks, or improper connections at the
vacuum hoses—Refer to "Emission Hose Routing
Diagram: ".
– The fuel system is operating lean. Refer to "Fuel
System Diagnosis: ".
– Vacuum leaks at the intake manifold or throttle
body
– Leaking crankcase ventilation system
– The engine control module grounds for being
clean, tight, and in the correct locations
– A high engine oil level condition—A high engine
oil level causes oil residue to form on the mass air
flow (MAF) sensor, causing a lean indication. The
MAF sensor does not need to be replaced.
➢ If the lean condition is common to only one bank of
the engine, inspect for the following conditions:
– Vacuum leaks that only affect one bank of the
engine—For example, the intake manifold, the
injector O-rings.
– Lean injectors—Refer to "Fuel Injector Solenoid
Coil Test: ".
– Missing, restricted, or leaking exhaust
components—Refer to "Symptoms - Engine
Exhaust: ".
– The heated oxygen sensor (HO2S) is installed
securely and the electrical connector is not
contacting the exhaust system.
– An engine mechanical condition—Refer to
"Symptoms - Engine Mechanical: ".
2. If all conditions test normal, refer to Diagnostic Aids.
Repair Instructions
Perform the "Diagnostic Repair Verification - Vehicle
Diagnostic Information: " after completing the diagnostic
procedure.
• "Fuel System Cleaning: "
• "Fuel Injector and Fuel Rail Replacement: "
• "Heated Oxygen Sensor Replacement - Bank 1
Sensor 1: "
• "Heated Oxygen Sensor Replacement - Bank 1
Sensor 2: "
• "Heated Oxygen Sensor Replacement - Bank 2
Sensor 1: "
• "Heated Oxygen Sensor Replacement - Bank 2
Sensor 2: "