Test Results
The time duration varies between 30 & 360 seconds depending on the resulting leak diagnosis test results (developed tank pressure "amperage" within a specific time period).
When the ECM detects a leak, a fault will be stored and the "Malfunction Indicator Light" will be illuminated. Depending on the amperage measurement detected by the ECM, the fault code displayed will be "small leak" or "large leak".
Scheme 5
Refuelling While a Leak Diagnosis is Taking Place: The ECM detects refuelling during a leak diagnosis as a result of the pressure drop when the fuel filler cap is opened and the increase pressure while filling the tank is being filled.
In this case, the leakage diagnosis is interrupted. The solenoid valve in the DM TL is switched off and the tank pressure escapes through the activated carbon canister.
If refuelling does not take place immediately after the fuel filler cap has been opened, the system will detect a large leak and the a fault will be stored in the ECM. If refuelling is detected in the next driving cycle (increase in fuel level), the fault is cleared.
The ECM detects refueling from a change in the fuel tank sending unit level. If the filler cap was not properly installed, when the leakage test is performed and leakage is detected; the variable indicator lamp (shown to the right) and the "Please Close Filler Cap" Check Control message will be displayed.
If the filler cap is correctly installed and leakage is not present the next time the test is performed, the "Malfunction Indicator Light" will not be illuminated.
Scheme 6
Starting with 2002 MY, a heating element was added to the DM TL pump to eliminate condensation.
The heater is provided battery voltage when KL15 is switched "on" and the ECM provides the ground path.
Scheme 7
Catalyst Monitoring is performed by the ECM under oxygen sensor closed loop operation. The changing air/fuel ratio in the exhaust gas results in lambda oscillations at the precatalyst sensors. These oscillations are dampened by the oxygen storage activity of the catalysts and are reflected at the post catalyst sensors as a fairly stable signal (indicating oxygen has been consumed). Conditions for Catalyst Monitoring
| Requirements | Status/Condition |
|---|---|
| Closed loop operation | YES |
| Engine coolant temperature | Operating Temp. |
| Vehicle road speed | 3 - 50 MPH (5 to 80 km/h) |
| Catalyst temperature (calculated) (1) | 350°C to 650°C |
| Valvetronic position deviation | Steady |
| Engine speed deviation | Steady/stable engine speed |
| Average lambda value deviation | Steady/stable load |
| (1) Catalyst temperature is an ECM calculated value based on load/air mass and time. | |
| (1) | Catalyst temperature is an ECM calculated value based on load/air mass and time. |
REQUIREMENTS STATUS/CONDITION
Note. The catalyst efficiency is monitored once per trip while the vehicle is in closed loop operation.
As part of the monitoring process, the pre and post O2 sensor signals are evaluated by the ECM to determine the length of time each sensor is operating in the rich and lean range.
If the catalyst is defective the post O2 sensor signal will reflect the pre O2 sensor signal (minus a phase shift/time delay), since the catalyst is no longer able to store/consume oxygen. The catalyst monitoring process is stopped once the predetermined number of cycles are completed, until the engine is shut-off and started again. After completing the next "customer driving cycle" whereby the specific conditions are met and a fault is again set, the "Malfunction Indicator Light" will be illuminated.
Secondary Air Injection Monitoring is performed by the ECM via the use of the pre-catalyst oxygen sensors. Once the air pump is active and is air injected into the exhaust system the oxygen sensor signals will indicate a lean condition. If the oxygen sensor signals do not change within a predefined time a fault will be set and identify the faulty bank(s). When diagnosing a Secondary Air Injection fault, in addition to the electric air pump and non-return valves always consider the following
- Restricted air inlet to the pump.
- Restricted supply hoses to the non-return valves.
- Internal restrictions in the cylinder head passages into the exhaust ports.
Misfire Detection is part of the OBD II regulations the ECM must determine misfire and also identify the specific cylinder(s), the severity of the misfire and whether it is emissions relevant or catalyst damaging based on monitoring crankshaft acceleration.
Emissions Diagnosis
The "BMW Fast" (BMW fast access for service and testing) diagnosis concept is used in the E65 for ME 9.2 ECM. This concept is based on the "Keyword Protocol 2000" (KWP 2000) diagnosis protocol defined as part of the ISO 14230 standard. Diagnosis communication takes place entirely on the basis of a transport protocol on the CAN bus. The Diagnosis bus is connected to the Central Gateway Module (ZGM).
Vehicle Diagnosis Access Point
The diagnosis tool is connected to the vehicle at the OBD diagnosis connector (On-Board Diagnosis). The connector is located behind a small cover in the drivers side kick panel trim. There is a black plastic cap that bridges KL30 to the D-bus when the connector is not being used. This cap must be removed before installing the diagnosis cable.
The TxD lead is located in pin 7 of the OBD socket and is connected directly to the ZGM.
The ZGM detects by means of the data transmission speed whether a BMW diagnosis tool (DISplus, MoDiC, GT-1) or an aftermarket scanner is connected.
The ECM allows access to different data depending on the diagnosis tool connected.
Note. When using an OBD scan tool for diagnosis, the transmission speed is 10.4 KBit/s.
Scheme 8
Diagnosis Bus
The aim of diagnosis is to enable a Technician to reliably identify a defective component. By the use of appropriate hardware and monitoring software, the microprocessor of the diagnosis tool is able to detect faults in the ECM and its peripherals.
Faults identified are stored in the fault memory and can be read out using the Diagnosis Program. Data transfer between the vehicle and the diagnosis tool takes place via the Diagnosis bus (D bus).
The new features of the diagnosis bus are
Scheme 9
- Faster data transmission speed of 115 kBd.
- Central diagnosis access point (OBD connector).
- Single diagnostic cable (TxD II) for the entire vehicle.
- Omission of the TxD1 cable.
- Access to diagnosis functions requires "Authorization".
- Diagnosis protocol "KWP 2000" (Keyword Protocol 2000).
- Standardized diagnosis structure for all control units.
The ECM is not directly connected to the OBD diagnostic connector. The OBD diagnostic connector is connected to the ZGM. The ECM is connected to the ZGM (central gateway module) by the PT CAN bus. The ECM is also connected to the Valvetronic control module by the Lo CAN (local) bus. Valvetronic faults are stored in the ECM.
Bi-VANOS Control (Variable Camshaft Adjustment)
Performance, torque, idle characteristics and exhaust emissions reduction are improved by Variable Camshaft Timing (Bi-VANOS). The VANOS units are mounted directly on the front of the camshafts and adjusts the timing of the Intake and Exhaust camshafts from retarded to advanced. The ECM controls the operation of the Bi-VANOS solenoids which regulates the oil pressure required to move the VANOS units. Engine RPM, load and temperature are used to determine Bi-VANOS activation.
Scheme 10
The Bi-VANOS mechanical operation is dependent on engine oil pressure applied to position the VANOS units. When oil pressure is applied to the units (via ports in the camshafts regulated by the solenoids), the camshaft hubs are rotated in the drive sprockets changing the position which advances/retards the intake/exhaust camshafts timing. The Bi-VANOS system is "fully variable". When the ECM detects that the camshafts are in the optimum positions, the solenoids maintain oil pressure on the units to hold the camshaft timing.
The operation of the VANOS solenoids are monitored in accordance with the OBD II requirements for emission control. The ECM monitors the final stage output control and the signals from the Camshaft Position Sensors for Bi-VANOS operation.
Solenoid Valves: The Bi-VANOS solenoid valves are mounted through the upper timing case front cover. There are two solenoids per cylinder head to control the oil flow to the camshaft ports for the intake and exhaust VANOS units.
The 4/3 way proportional solenoid valve is activated by the ECM to direct oil flow. The solenoid valve is sealed to the front cover by a radial seal and secured by a retaining plate.
