DDEC TROUBLESHOOTING
[b] If the IVS input is OFF with the TPS count being less than 120, refer to section 68.3.6.
68.3.6
Check Resistance Between Idle Validation Switch Contacts
Perform the following steps to determine resistance:
1. Turn vehicle ignition switch to the ON position.
2. Measure resistance between the ECM input at the TPS/IVS end of the harness and battery
ground.
[a] If the resistance is less than 100 , the IVS is defective. Replace the switch. (Contact
the OEM for procedure.) Verify repairs. Refer to section 68.3.7.
[b] If the resistance is greater than 100 , either the IVS input or #953 wire is open or
the IVS is defective. Replace the switch. (Contact the OEM for procedure.) Verify
repairs. Refer to section 68.3.7.
68.3.7
Verify Repairs
Perform the following steps to verify repairs:
1. Clear inactive codes.
To avoid personal injury, before starting and running the
engine, be sure that the vehicle is parked on a level surface
and that the wheels are properly blocked.
2. Start and run the engine.
3. Depress foot pedal to at least half throttle (>290 counts).
4. Release foot pedal and allow the engine to idle.
5. Visually observe the check engine light (CEL) and DDR.
[a] If the CEL comes on, no further troubleshooting is required.
[b] If code 68 is logged, refer to section 68.3.1 to troubleshoot Flash Code 68 again.
All information subject to change without notice.
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION
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