Engine Controls - Trouble Shooting - No Codes: Other Saab 9-3 I

DIFFICULT TO START

1. Check battery and cables, charging system and fusible links.
2. Check ignition switch.
3. Check clutch start switch (M/T) or neutral start switch (A/T).
4. Check starter and wiring connections.

ROUGH OR UNSTABLE IDLE

1. Check Engine Coolant Temperature (ECT) sensor operation.
2. Check Manifold Absolute Pressure (MAP) sensor.
3. Check for proper CO setting (if adjustable) on mass airflow sensor. Inspect for broken mass airflow sensor filament (if equipped). Check mass airflow sensor continuity.
4. Inspect induction system. Inspect for vacuum leaks downstream of throttle valve. Inspect duct between mass airflow sensor and throttle body.
5. Check idle speed.
6. Check injector operation and opening duration. Inspect injectors for leaks.
7. Ensure fuel pump is okay. Check fuel pressure and pressure regulator. Inspect for leaks in fuel lines or restrictions in return line.
8. Ensure electrical harness, connectors and wires are not broken or loose. Check all input signals to ECM.
9. Check oxygen sensor.

ENGINE HESITATES OR MISSES

1. Check Manifold Absolute Pressure (MAP) sensor.
2. Ensure wiring harness, connections and wires are not broken or loose. Check ECM connector pins and all ECM input signals.
3. Check charging system for low output or poor ground connection. Check all electrical connections for tightness.
4. Check fuel injector operation and opening duration. Inspect injectors for leaks.
5. Check turbo system for proper operation.
6. Verify mass airflow sensor filament is not broken.
7. Inspect induction system. Inspect for vacuum leaks downstream of throttle valve. Inspect duct between mass airflow sensor and throttle body.
8. Verify fuel pump is okay. Check fuel pressure and pressure regulator. Inspect for leaks in fuel lines or restrictions in return line.
9. Check Engine Coolant Temperature (ECT) sensor.
10. Check Throttle Position (TP) sensor.
11. Check trigger signals to ignition discharge module (IDM).

POOR FUEL MILEAGE

1. Ensure fuel pump is okay. Check fuel pressure and pressure regulator. Inspect for fuel leaks or restrictions in return line.
2. Check injector operation by individually unplugging connectors. Engine RPM should drop noticeably. Check opening duration. Inspect injectors for leaks.
3. Check Engine Coolant Temperature (ECT) sensor.
4. Check Manifold Absolute Pressure (MAP) sensor.
5. Check Intake Air Temperature (IAT) sensor.
6. Check Throttle Position (TP) sensor.
7. Verify mass airflow sensor filament is not broken.
8. Ensure electrical harness, connectors and wires are not broken or loose. Check all input signals to ECM.

ENGINE WILL NOT START

1. Ensure electrical harness, connectors and wires are not broken or loose. Check component grounding points. Ensure battery voltage is at least 11.5 volts. Check system relay and fuel pump relay. Check Charge Air Absolute Pressure (CAAP) switch. Check all ECM input signals.
2. Using TECH 2 scan tester and spark plug grounding lead, verify spark exists at plugs.
3. Ensure fuel pump operates. Check fuel pressure and pressure regulator. Inspect for plugged fuel filter or restrictions in return line.
4. Check fuel injector operation.
5. Inspect induction system. Inspect for leaks downstream of throttle valve. Inspect duct between mass airflow sensor and throttle body.
6. Check Engine Coolant Temperature (ECT) sensor operation.

ENGINE STARTS BUT STOPS

1. Ensure electrical harness, connectors and wires are not broken or loose. Ensure battery voltage is at least 11.5 volts. Check main relay and fuel pump relay. Check turbo pressure switch. Check all ECM input signals.
2. Check Manifold Absolute Pressure (MAP) sensor.
3. Check Engine Coolant Temperature (ECT) sensor operation.
4. Inspect induction system. Inspect for leaks downstream of throttle valve. Inspect duct between mass airflow sensor (if equipped) and throttle body.
5. Check throttle position sensor (TPS).

POOR RESPONSE ON ACCELERATION

1. Check Mass Airflow (MAF) sensor for broken filament. Check mass airflow sensor resistance.
2. Inspect induction system. Inspect for leaks downstream of throttle valve. Inspect duct between MAF sensor and throttle body.
3. Check idle speed.
4. Check injector operation and opening duration. Inspect injectors for leaks.
5. Verify fuel pump is okay. Check fuel pressure and pressure regulator. Inspect fuel line for leaks or restrictions. Check fuel filter.
6. Ensure electrical harness, connectors and wires are not broken or loose. Check all input signals to ECM.
7. Check Engine Coolant Temperature (ECT) sensor.
8. Check oxygen sensor.
9. Check turbocharger, wastegate and vacuum controls for wear or damage.

LACK OF POWER

1. Inspect induction system. Inspect for air leaks downstream of throttle valve. Inspect duct between mass airflow sensor and throttle body.
2. Inspect throttle valve for binding and proper adjustment. Ensure throttle valve opens completely. NOTE: On Trionic T-7 Engine Management System, perform this test with ignition off for at least 10 seconds, otherwise Limp-Home Solenoid may engage and set DTC.
3. Verify fuel pump is okay. Check fuel pressure and pressure regulator. Inspect for leaks or restrictions in fuel line. Check fuel filter.
4. Check injector operation by individually unplugging connectors. Engine RPM should drop noticeably. Check opening duration. Inspect injectors for leaks.
5. Check Manifold Absolute Pressure (MAP) sensor.
6. Verify Mass Airflow (MAF) sensor filament is not broken and burn-off function is working (if equipped).
7. Check turbo system for proper operation.
8. Check Engine Coolant Temperature (ECT) sensor operation.
9. Check Intake Air Temperature (IAT) sensor operation.
10. Ensure electrical harness, connectors and wires are not broken or loose. Check all input signals to ECM.

Intermittent Simulation

To reproduce the conditions creating an intermittent fault, use the following methods

1. Lightly vibrate component.
2. Heat component.
3. Wiggle or bend wiring harness.
4. Spray component with water mist.
5. Remove/apply vacuum source. Monitor circuit/component voltage or resistance while simulating intermittent fault. If engine is running, monitor for self-diagnostic codes. Use test results to identify a faulty component or circuit.