Electronic Idle Speed Control Test

Testing Electronic Idle Speed Control








Testers connect:
Telethermometer (018) 124 589 07 21 00,
Trigger clamp (011),
Engine tester (026),
Multimeter (003),
Test cable (034) 102 589 04 63 00.

Extraction device (014) position at exhaust tail pipe.
Engine oil temperature approx. 80° C.
Electronic idle speed control test (refer to table).
Operation of idle speed air valve test by briefly applying battery voltage.
Power supply test according to wiring diagram.
Engine running test by switching on all ancillaries.

Idle Speed, Current At Idle Speed Air Valve:

Special Tools:

Commercial Testers:

Note:
Idle speed control is independent of air flow sensor potentiometer. Engine oil temperature approx. 80 °C, selector lever in position "P" or N", A/C compressor switched off and no leaks in intake system. Idle contact, coolant temperature sensor and exhaust gas recirculation operating properly.

At high altitudes (>2000 m) current consumption may drop below 700 mA as the actuator requires to open a significantly greater cross section at such altitudes to stabilize the engine.


Road speed signal

The test should only be performed if the following complaint is received: "Bucking when car running with closed throttle valve".

Pin assignment of electronic idle speed control (ELR) unit (N8)






Connector:

1. Electronic speedometer (A1 p8), road speed signal

2. CIS-E injection system control unit (N3), contact 9, temperature signa/ (TF)

3. A/C compressor control unit (N6), contact 4

4. Throttle valve switch, full load/idle speed detection, contact 1

5. not assigned

6. Idle speed air valve (Y6)

7. Idle speed air valve (Y6)

8. not assigned

9. Overvoltage protection relay (K1, K1/1), contact 2, power Supply terminal 15

10. Electronic ignition EZL control unit (N1/2, N1/S), TP/TN signal

11. Model 126: Engine ground (W10)

12. Starter lockout and backup light switch (S16/1), gear detection.

Symbols For Testers:

Test Steps 1.0 - 3.3:

Test Steps 4.0 - 5.2:

Test Steps 6.0 - 7.1:

Note:
Distributor line for idle air






Modified shape of distributor line with additional longitudinal rib on inside (arrow) for distributing idle air.

A 1st version
B 2nd version






Hose connections on left and right lengthened Size C = 53 mm (previously 42 mm)