Unfused Components

References (WH), Commercially Available Tools:

1 Determine unfused components, these are eg.:
Consumers of the exhaust gas recirculation (EGR) system.
Consumers of the airbag (AB) system.
Consumers of the knock sensor system (KSS).
Consumers of the electronic ignition (HFM-SFI/PEC) system.
Anti-theft systems, eg. immobilizer.
Consumers of the idle speed control (ISC) system and alternator, starter, ignition switch.

See "Electric wiring diagrams, models 163, 170, 202, 208, 210". Observe after-running time for electronic components:
Models 163, 202, 208, 210 approx. 4 min., model 170 approx. 10 min.

2 Read off total quiescent current on multimeter connected to battery and note value.
3 Separate coupling or connection the likely quiescent current consumer and tie back, if necessary, to prevent contact.


NOTE: The quiescent current consumption may also rise as a result of the radio by about 0.240 A (240 mA). The increased quiescent current consumption can be eliminated by switching the radio on and off.


NOTE: On vehicles with auto-pilot system (APS) the quiescent current increases to approx. 800 mA while the processor is booting (approx. 30 minutes) after inserting the APS processor fuse.


If the decrease in the quiescent current is <= 0.02 A (20 mA) or <= 0.035 A (35 mA), for immobilizer control module:
Component is in order.

5 Plug in coupling or connection again to the component.
6 Repeat test as described with all the possible quiescent current consumers.


If the decrease in the quiescent current is > 0.02 A (20 mA) or > 0.035 A (35 mA), for immobilizer control module:
Replace component.

Once again test quiescent current as a check.