Specifications

Testing Testing Electronic Throttle Systems

Bosch EML for M70 and S70 Engines

This is the first, full drive-by-wire electronic throttle system (used in U.S. only on the 7 and 8

Series). On the V12, a separate control module called EML synchronizes and controls dual throttle

valve assemblies called DKs.

Whenever power has been disconnected or EML components have been replaced, the EML

system usually requires adaptation to synchronize and coordinate system components. Use the

following throttle synchronization procedure for the M70 engine.

z To synchronize the EML throttle:

1. Disconnect the battery for at least 1 hour.

2. Connect the battery and start the engine. Let the engine reach operating temperature without

touching the accelerator pedal.

3. With the transmission in first gear, accelerate until engine speed is over 5000 RPM.

4. Release the accelerator pedal and coast until engine is at idle.

5. Repeat the above operation two consecutive times.

6. Allow the engine to idle in neutral or park for at least 5 minutes.

7. Turn the engine off.

8. Restart the engine.

The EML throttle should now be synchronized.

EML IIIS for E38 (V12)

The EML IIIS came out in approximately 1995 in the U.S. and is used on E38, M73, and M73TU

engines (5.4L V12). This system has the EML module installed on the CAN communication bus.

This system uses two throttle valve assemblies mounted on each intake manifold. There is only

one pedal position sensor (PWG) connected to the accelerator pedal.

The EML IIIS control module uses two separate processors. Each throttle valve is controlled by

two separate stepper motors, which are each controlled separately by the two processors. On this

system, the PWG sensor is not a potentiometer or a Hall effect sensor. Instead, it uses three

separate inductive coils, each coil supplied with an AC voltage at a specific frequency from the

EML module. As the pedal is moved, the concentric shape of the iron core moves closer to the

PWG coils changing the inductance of the coils. This increasing inductance reduces the amplitude

of the AC frequency.

The throttle valves are synchronized automatically. The EML III control module processes both

signals from the two DME control modules. If there is a difference (under 10%) the EML adjusts

the throttle valves to achieve equal air on both banks. Over 10% difference will set a fault code and

the system will not be synchronized.

Important Tips for Testing EML Systems

•

The BMW software currently does not display data from the EML module. On vehicles with

EML IIIS, there may be no or limited throttle-related parameters available in the DME data.

• The EML module stores up to five codes. If more faults are present, then higher priority faults

will displace lower priority faults.