Test Groups 1BMXT03.0E5R, 1BMXT03.0E53, 1BMXV02.5M54, 1BMXV03.0LEV, 1BMXV03.0LER, 1BMXV03.0M54 & 1BMXV03.0M5R
WARNING: This page does not describe the selected car, but rather 13 other vehicles, including the 2001 BMW Z3, 2001 BMW X5, 2001 BMW M3, 2001 BMW M Roadster, and 2001 BMW M Coupe. 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 Fig 1.
- 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 Fig 2.
- During PRESSURE TEST, purge valve needs to be shut. After test, canister purge is resumed and consequently the remaining pressure in the evaporative system is bled off. See Fig 3.
- Monitoring Structure Of Leak Measurement - See Fig 4 and Fig 5 .
- Diagnosis Frequency & MIL Illumination -
See Fig 6-Fig 7
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Courtesy of BMW OF NORTH AMERICA, INC.
- Evaporative Purge System Flow Check - Purge flow from charcoal canister through purge valve is monitored after coolant temperature has reached a fixed minimum value. The diagnosis is started during regular purging.
- Monitoring Process Of Evaporative Purge System Flow Check
- Step 1 - For Rich Or Lean Mixture - Flow through purge valve is assumed as soon as the lambda controller is compensating for a rich or a lean shift. After this procedure, diagnosis is completed and evaporative purge system resumes working normally. See Fig 8.
- 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.