10.11
MISCELLANEOUS DIGITAL INPUT FAULT
The following procedure will troubleshoot an input fault.
10.11.1 Verify Switch Status
Follow these steps to verify the switch status.
1. Turn ignition ON.
2. Plug in DDR.
3. Select switch light status.
4. Operate the engine or vehicle that would allow the feature to activate (e.g. activate
switch, set brake, etc.).
5. Observe the status when the feature is active (or supposed to be active). See Figure 10-9.
[a] The feature always reads OFF. Refer to section 10.11.2.
[b] The feature switches from OFF to ON. Refer to section 10.11.3.
[c] The feature always reads ON. This indicates the input wire is shorted to ground or the
switch is faulty. Repair wire or replace switch. Refer to section 10.11.4.
Figure 10-9
ECM Vehicle Harness Connector
10.11.2 Check for Open
Perform the following steps to check for an open:
1. Turn ignition OFF.
2. Unplug the vehicle interface harness connector at the ECM.
All information subject to change without notice.
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6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION
