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Home >> Suzuki >> 2007 >> XL7 Limited, FWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine General Information And Diagnosis >> Diagnostic Information and Procedures >> DTC P2177, P2179, P2187, or P2189 >> Circuit/System Testing
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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) and 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 .
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