DTC P1451-P1453: FUEL TANK PRESSURE (FTP) SENSOR MALFUNCTION Saab 9-5 I

Note. For DTC P1453, start diagnosis at step 2 . For DTC P1451 and P1491, start diagnosis at step 4 .

1. Trace vacuum hose from intake manifold to EVAP canister purge valve. (Схема №2)or (Схема №5). Disconnect hose from purge valve and attach pressure/vacuum pump to valve. Apply vacuum to valve. If vacuum does not hold, replace EVAP canister purge valve and go to step 8. If vacuum does hold, go to next step. NOTE: Performing the following step requires use of Kent-Moore EVAP system pressurizing equipment SST No. J41413 and service manual.
2. Connect Kent-Moore SST J41413 to filler cap adaptor and fuel filler pipe. Connect TECH 2 scan tool to Data Link Connector (DLC). Turn ignition on. Select ACTIVATE: SHUT-OFF VALVE. Following Kent-Moore instruction manual, pressurize EVAP system. Turn shut-off valve off. If system no longer holds pressure, go to step 4. If system is still holding pressure, go to next step.
3. Problem is caused by blockage between fuel tank and EVAP shut-off valve atmospheric port. Inspect carbon filter, shut-off valve, hose between tank and carbon filter, and hose between shut-off valve and carbon filter. Repair as necessary. Go to step 8.
4. Disconnect FTP sensor electrical connector located on top of fuel tank. (Схема №16) Turn ignition on. Use DVOM to measure voltage between FTP sensor harness connector terminal No. 1 (White/Black wire) and ground. If voltage reading is between 4.9-5.1 volts, go to next step. If voltage is not as specified, repair faulty circuit between FTP sensor harness connector terminal No. 1 and ECM harness connector terminal No. 46 (White/Black wire). (Схема №1), (Схема №3) or (Схема №4) for ECM location. (Схема №11)for ECM terminal identification. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-3491) article. Go to step 8.
5. Use DVOM to measure voltage between FTP sensor harness connector terminals No. 1 (White/Black wire) and 2 (Green/Red wire). If voltage reading is between 4.9-5.1 volts, go to next step. If voltage is not as specified, repair faulty circuit between FTP sensor harness connector terminal No. 2 and ECM harness connector terminal No. 70 (Green/Red wire). Go to step 8.
6. Use TECH 2 scan tool to select TEST VALUE: FUEL TANK PRESSURE. With ignition on and FTP sensor harness connector unplugged, scan tool display should read about 2.500 kPa. If reading is as specified, go to next step. If reading is not as specified, repair faulty circuit between FTP sensor harness connector terminal No. 3 and ECM harness connector terminal No. 59 (Orange/White wire). Go to step 8
7. Connect fused jumper wire between FTP sensor harness connector terminals No. 2 (Green/Red wire) and 3 (Orange/White wire). If scan tool display reads -2.500 kPa, replace FTP sensor. See «FUEL TANK PRESSURE (FTP) SENSOR»(ref-2997-S39753307622000041700000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION article. If scan tool display is not as specified, repair faulty circuit between FTP sensor harness connector terminal No. 3 and ECM harness connector terminal No. 59 (Orange/White wire). Go to next step.
8. Connect TECH 2 scan tool to Data Link Connector (DLC). DO NOT touch brake pedal. Start engine and allow it to idle at least 4 minutes and until coolant temperature exceeds 140°F (60°C). Check diagnostic status of DTC P1452. If scan tool display reads OK, clear all system DTCs. If display reads NOT READY, restart test procedure by rolling vehicle forward or back several feet and reselecting INITIATING DIAGNOSTICS. If DTC P1452 is displayed, substitute known good ECM and retest system. See «ENGINE CONTROL MODULE (ECM)»(ref-2997-S17585372472000041700000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article.