2002 2BMXV03.0LER, 2BMXV03.0M5R & 2BMXT03.0E5R
WARNING: This page does not describe the selected car, but rather 18 other vehicles, including the 2002 BMW Z8, 2002 BMW Z3, 2002 BMW X5, 2002 BMW M5, and 2002 BMW M3. However, it is still accessible from the selected car via links, so may be relevant.
- Evaporative System Leak Measurement -
Evaporative system monitoring permits detection of leaks in evaporative system with a diameter of .019" (.5 mm) and up. Using a Diagnostic Module-Tank Leakage (DM-TL), an electrical actuated pump located at atmospheric connection of evaporative canister, a pressure test of evaporative system is performed in following order:
- During REFERENCE LEAK MEASUREMENT, electrical actuated pump delivers through reference restriction. Engine-management system measures pump electrical current consumption in this section. See Figure.
- During LEAK MEASUREMENT, electrical actuated pump delivers through charcoal canister into fuel tank system. Pressure in evaporative system may be up to 25 kPa depending on fuel level in tank. Engine-management system measures pump electrical current consumption. A comparison of currents of reference leak measurement and leak measurement is a measure for leakage in tank. See Figure.
- After test, remaining pressure in evaporative system is bled off through charcoal canister by switching off pump and solenoid. See Figure.
- Monitoring Structure Of Leak Measurement - See Figure-Figure .
- Diagnosis Frequency & MIL Illumination - See Figure-Figure .
- Evaporative Purge System Flow Check - Purge flow from charcoal canister through purge valve is monitored after fuel system adaptation is completed and lambda controller is at closed loop condition. Diagnosis is started during regular purging.
- Monitoring Process Of Evaporative Purge System Flow Check
- Step 1 - For Rich Or Lean Mixture - Flow through the purge valve is assumed as soon as the lambda controller is compensating for a rich or a lean shift. After this procedure the diagnosis is completed and the evaporative purge system resumes working normally. See Fig 1.
- Step 2 - For Stoichiometric Mixture Or First Step Fails - In this case, lambda controller does not need to compensate for a deviation. Therefore, after finishing regular purging, purge valve is opened and closed abruptly several times. Effect of additional cylinder charge triggers a variation of engine idle speed. If a predetermined value is reached, diagnostic procedure is completed.
- Step 3 - For Stoichiometric Mixture Or Second Step Fails - If threshold at second step is not reached, an additional procedure is performed. Purge valve is opened and idle air control valve simultaneously is closed to compensate idle speed increase. The effect is a decrease of measured idle air mass by mass airflow sensor. If a predetermined value is reached, diagnosis procedure is completed.