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Home >> Saab >> 1999 >> 9-3 Base, 4D Hatchback, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - TRIONIC T5 Fuel Control System >> Diagnostic Tests >> DTC P1171-P1172: Closed Loop Malfunction

DTC P1171-P1172: Closed Loop Malfunction

  1. Connect TECH 2 scan tool to DLC. Turn ignition on. Check for presence of DTCs. If DTC(s) P1416, P0106-P0108, P0112-P0113, P0117, P0118, P0121-P0123, P0125, P0132, P0133, P0135, P0441, P0442, P0444 or P0445 are present, go to appropriate diagnostic test. If DTCs are not present, go to next step.
  2. Check for vacuum leaks, moisture or corrosion at MAP sensor and connector located under passenger side engine compartment brace. Inspect fuel pressure regulator hose for damage or leaks. If no problems are found, go to next step. If any problems are found, repair as necessary and go to step  8 .
  3. Use scan tool to select READING: INTAKE PRESSURE. If scan tool reading is about 102 kPa, go to next step. If reading is not as specified, replace MAP sensor and go to step  8 .
  4. Disconnect MAP sensor vacuum hose. Connect vacuum/pressure pump to MAP sensor vacuum port. Apply about 8.7 psi to MAP sensor while observing scan tool display. If reading is now between 155-165 kPa, go to next step. If reading is not as specified, replace MAP sensor and go to step  8 .
  5. Apply about 17.7 in. Hg of vacuum to MAP sensor while observing scan tool display. If reading is now between 35-45 kPa, go to next step. If reading is not as specified, replace MAP sensor and go to step  8 .
  6. Disconnect HO2S-1 harness connector. Use jumper wires to connect a 1.5 volt battery positive terminal to HO2S-1 harness connector terminal No. 4 (Green wire) and battery negative terminal to HO2S-1 harness connector terminal No. 3 (Brown/White wire). Use scan tool to select READING: O2S 1. Scan tool reading should be about 1.4 volts. If reading is as specified, go to next step. If reading is not as specified, check for faulty circuit between HO2S-1 harness connector terminal No. 3 and ECM harness connector terminal No. 47 (Brown/White wire) or between HO2S-1 harness connector terminal No. 4 and ECM harness connector terminal No. 23 (Green wire). See Figure for ECM terminal identification. Repair as necessary and go to step  8 .
  7. Remove hose from EVAP canister purge valve that goes to EVAP vapor canister. Connect vacuum/pressure pump to open purge valve port and apply vacuum. Ensure that purge valve holds vacuum when key is off (no voltage to valve). Check for exhaust leaks ahead of HO2S-1. Inspect fuel system pressure and flow. See FUEL PRESSURE/FLOW TESTS under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. If any problems are found, repair as necessary. If no problems are found, replace HO2S-1. Go to next step.
  8. Use scan tool to clear DTCs. Start engine and allow it to idle until coolant temperature reaches 140°F (60°C), then allow engine to idle for another 5 minutes. Recheck for any stored DTCs. If DTCs P1171-P1172 are present, substitute known good ECM and retest system. See ENGINE CONTROL MODULE (ECM) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article.
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