DDEC TROUBLESHOOTING
68.3 TROUBLESHOOTING FLASH CODE 68
The following procedure will troubleshoot Flash Code 68.
68.3.1
Check for Idle Validation Switch Code
Perform the following steps to check for IVS active code:
1. Turn ignition ON.
2. Plug in DDR.
3. Cycle foot pedal; then read codes.
[a] If the IVS code is open (FMI=5), validate the throttle pedal application.
Refer to section 68.3.4.
[b] If the IVS code is grounded (FMI=6), check the IVS switch. Refer to section 68.3.2.
68.3.2
Check the Idle Validation Switch
Perform the following step to check the idle validation switch:
1. Turn the vehicle ignition switch to the ON position.
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.
NOTE:
Vehicle need not be moving to perform this check.
3. Plug in DDR.
4. Compare idle validation switch input status (switch light status) with the throttle position
sensor counts.
[a] If the IVS status is ON with the TPS count being greater than 282, measure for
resistance. Refer to section 68.3.3.
[b] If the IVS status is OFF with the TPS count being greater than 282, clear inactive
codes. No further troubleshooting is required. Refer to section 68.3.7.
68.3.3
Check Resistance Between Idle Validation Switch Contacts
Perform the following steps to measure resistance:
All information subject to change without notice.
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION
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