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Home >> Suzuki >> 2001 >> Swift GA, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0451: EVAP System Pressure Sensor Performance >> Diagnosis & Repair Procedure

Diagnosis & Repair Procedure

  1. Perform DTC CONFIRMATION TEST . If DTC P0451 is set, go to next step. If DTC P0451 is not set, problem is intermittent. System is okay at this time. See TROUBLE SHOOTING - NO CODES article.
  2. If not using scan tool, go to next step. If using scan tool, turn ignition off and connect scan tool. Open fuel filler cap. Turn ignition on. Scan tool should display FUEL TANK PRESSURE of 0 in. Hg. If reading is as specified, go to step  5. If reading is not as specified, go to step  4.
  3. Open fuel filler cap. Turn ignition on. Measure voltage (backprobe) between ground and PCM 22-pin connector C23 terminal No. 21 (Light Green/Yellow wire). See Figure. If reading is not 2.0-2.5 volts, go to next step. If reading is 2.0-2.5 volts, go to step  5.
  4. Check FTP sensor. See FUEL TANK PRESSURE SENSOR under FUEL EVAPORATION in SYSTEM & COMPONENT TESTING article. Replace as necessary and go to DTC CONFIRMATION TEST . If FTP sensor is okay, check for short or open in circuits between FTP sensor and PCM. See WIRING DIAGRAMS article. If circuits are okay, replace PCM and go to DTC CONFIRMATION TEST .
  5. Check FTP sensor. See FUEL TANK PRESSURE SENSOR under FUEL EVAPORATION in SYSTEM & COMPONENT TESTING article. Replace as necessary and go to DTC CONFIRMATION TEST . If FTP sensor is okay, go to next step.
  6. Check EVAP canister air filter for contamination (mud or water) and ensure air passage is not plugged. Replace as necessary and go to DTC CONFIRMATION TEST . If air filter is okay, go to next step.
  7. Check EVAP canister air valve. See EVAP CANISTER AIR VALVE CIRCUIT under FUEL EVAPORATION in SYSTEM & COMPONENT TESTING article. Replace as necessary, and go to DTC CONFIRMATION TEST . If EVAP canister air valve is okay, problem is intermittent. System is okay at this time. See TROUBLE SHOOTING - NO CODES article.
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