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Home >> Suzuki >> 2002 >> Grand Vitara JLS, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0451: EVAP Circuit, Pressure Sensor Range/Performance Problem >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

  1. Check for DTCs P1450 and P1451. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If DTCs are not set, go to next step. If any DTC is set, go to that test first.
  2. 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 INTERMITTENTS TROUBLE SHOOTING - NO CODES article.
  3. If not using scan tool, go to next step. If using scan tool, turn ignition off. Connect scan tool. Remove fuel filler cap. Turn ignition on. Observe FUEL TANK PRESS reading on scan tool. If FUEL TANK PRESS reading is not about zero kPa, go to step  5 . If FUEL TANK PRESS reading is about zero kPa, check fuel tank pressure control system. See FUEL EVAPORATION in SYSTEM & COMPONENT TESTING article. If fuel tank pressure control system is okay, replace ECM (PCM) and go to DTC CONFIRMATION TEST  .
  4. Remove fuel filler cap. Backprobing, measure voltage between ECM (PCM) 35-pin connector E61 terminals No. 20 (Brown/Red wire) and No. 32 (Gray/Yellow wire). See Figure . Turn ignition on. If 2.0-2.5 volts do not exist, go to next step. If 2.0-2.5 volts exist, check fuel tank pressure control system. See FUEL EVAPORATION in SYSTEM & COMPONENT TESTING article. If fuel tank pressure control system is okay, replace ECM (PCM) and go to DTC CONFIRMATION TEST  .
  5. Turn ignition off. Disconnect 12-pin FTP sensor harness connector. See Fig 1 . Measure voltage between harness side of 12-pin FTP sensor harness connector terminals No. 7 (Gray/Yellow wire) and No. 8 (Gray/Red wire). Turn ignition on. If 4.5-5.5 volts exist, go to step  7 . If 4.5-5.5 volts do not exist, go to next step.
  6. Check for open or short in Gray/Red wire or Gray/Yellow wire between 12-pin FTP sensor harness connector and ECM (PCM) 35-pin connector E61 terminals No. 32 and No. 33. Repair as necessary and go to DTC CONFIRMATION TEST  . If wires are okay, replace ECM (PCM) and go to DTC CONFIRMATION TEST  .
  7. Check for open or short in Brown/Red wire between 12-pin FTP sensor harness connector terminal No. 6 and ECM (PCM) 35-pin connector E61 terminal No. 20. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Repair as necessary and go to DTC CONFIRMATION TEST  . If wire is okay, check for open or short in Brown/Red wire between 12-pin FTP sensor harness connector and FTP sensor. Repair as necessary and go to DTC CONFIRMATION TEST  . If wire is okay, go to next step.
  8. Check FTP sensor operation. See FUEL EVAPORATION in SYSTEM & COMPONENT TESTING article. Replace as necessary and go to DTC CONFIRMATION TEST  . If FTP sensor is okay, replace ECM (PCM) and go to DTC CONFIRMATION TEST  .
Fig 1: Identifying Fuel Tank Pressure Sensor Harness Connector Location
G00056786Courtesy of SUZUKI OF AMERICA CORP.
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