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Home >> Suzuki >> 2004 >> Vitara RWD, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 4 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P1171: Fuel System Lean During Acceleration >> Diagnostic Procedure
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Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Isuzu Trooper. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform ON-BOARD DIAGNOSTIC II SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD-II system check, go to next step.
  2. If any other component-related DTCs are set, diagnose them first. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no other DTC is present, go to next step.
  3. Check fuel level. Add fuel if tank is almost empty. If fuel was added, go to next step. If no additional fuel was required, go to step  5.
  4. Start vehicle and bring engine to normal operating temperature 167-203°F (75-95°C). Increase engine speed to 1200 RPM. Using scan tool, observe Bank 2 HO2S No. 1 voltage parameter. HO2S voltage should vary between 100-900 millivolts, and quickly move to upper end of specification when throttle is snapped open. If voltage parameter performs as specified, perform FUEL SYSTEM ELECTRICAL CHECK in SYSTEM & COMPONENT TESTING article. If voltage reading is not as specified, go to next step.
  5. Turn ignition off. Remove fuel pump relay and crank engine to relieve fuel pressure. Install fuel pressure gauge. Replace fuel pump relay and start engine, bring engine to normal operating temperature and allow it to idle. Disconnect vacuum line to fuel pressure regulator and read pressure gauge. Fuel pressure should be 41-46 psi (2.8-3.25 kg/cm2 ). If pressure reading is as specified, Perform ON-BOARD DIAGNOSTIC II SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. If pressure reading is not as specified, go to next step.
  6. Check for restricted fuel lines or filter. If problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, go to next step.
  7. Turn ignition off. Remove fuel pump relay. Connect fused jumper wire between fuel pump relay battery feed terminal and fuel pump fuse terminal. See WIRING DIAGRAMS article. With fuel pressure gauge still connected, pinch off fuel return line. Do not allow fuel pressure to exceed 60 psi (4.2 kg/cm2 ). Manipulate fuel line to raise pressure to more than 46 psi (3.25 kg/cm2 ). If pressure increases to more than 46 psi (3.25 kg/cm2 ), check for an intermittent problem. See DIAGNOSTIC AIDS . If pressure does not increase as specified, go to next step.
  8. Check for faulty fuel pump, restricted fuel pump strainer, incorrect fuel pump, incorrect fuel grade or cold fuel. If any problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM.
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