Testing Electronic Idle Speed Control (ELR)

Testing electronic idle speed control (ELR)

Engine 606.910

Connection Diagram Of Digital Tester Without Adapter, Location Of Components:

Connection Diagram Of Pulse Counter, Hand-held Tester:

013 Pulse counter
087 Hand-held tester
X11/4 Test coupling for diagnosis (16-pin)
G1 Battery

Pulse counter

Black cable Terminal 31 (ground) or contact 1
Red cable Terminal 15 (ignition), terminal 30 (battery) or contact 16
Yellow cable Contact 4 (ARA, ELR/ARA control unit)

Hand-held tester

Black cable Terminal 31 (ground) or contact 1
White cable Terminal 15 (ignition) or contact 16
Red cable Terminal 30 (battery), X4/1O (terminal block) or contact 3
Yellow cable Contact 4 (ARA, ELR/ARA control unit)






Connect digital tester (001) and pulse generator (021).
Check accelerator control for ease of movement.
Check idle speed stop at Bowden cable (32); the spring plate (29/7) must be resting free of tension against the compression spring (29/8).
Test overvoltage protection fuse.
Test battery voltage, approx. 12 V. Measured at overvoltage protection between contacts 1 and 5.
Warm engine to coolant temperature of 60 - 80°C.

Test with pulse counter

Disconnect pulse counter (013) to battery (G1) and to test coupling X11/4) connect according to connection diagram.

Note: LED U-Batt in display panel must come on; if not
a) Test fuse of pulse counter.
b) Test contact 1 of test coupling X11/4) to battery positive (approx. 11 - 12 V).
c) Test contact 4 of test coupling X11/4) to contact 1 (approx. 6 - 12 V).

Run engine at idle speed.
Press start button of pulse counter (013) for 2 - 4 seconds.
Rear display and note.
Readout "1": no fault
Readout greater than "1": fault in system

Press start button of pulse counter (013) once again for 2 - 4 seconds
If there is no further fault in the system. the previous readout reappears. If there is a further fault in the system, its fault code is displayed.
Rectify noted faults after test program: "testing individual components".
Erase fault memory by pressing start button of pulse counter and reading rectified fault. Then press start button for 6 - 8 seconds.

Note: Each fault displayed must be erased individually. Once the fault is recitified and erased, the fault code no longer appears during fault output. A digit greater than 1 displayed, further faults in system.

Test with hand-held tester

Connect hand-held tester (087) according to connection diagram. The test cycle is integrated in the HHT program

Note: Reading, erasing fault memory, see operating instructions of hand-held tester.

Special tools









Function test






Testing individual components