DDEC TROUBLESHOOTING
[b] If the resistance is less than or equal to 1,000 , the signal line #525 is shorted to the
return line. Repair the short. Refer to section 11.3.12.
Figure 11-4
Variable Speed Governor Circuit
11.3.8
Check for Open Signal
Perform the following steps to check for open signal:
1. Install a jumper wire between sockets A and B of the hand throttle sensor harness
connector. See Figure 11-4.
2. Enable VSG. Refer to OEM guidelines.
3. Measure resistance between sockets D1 (#510) and C3 (#952) on the vehicle harness
connector.
[a] If the resistance is less than or equal to 5 , refer to section 11.3.9.
[b] If the resistance is greater than 5
or open and the signal line (#510) or return line
(#952) is open, repair the open. Refer to section 11.3.12.
11.3.9
Check ECM Connectors
Perform the following steps to check for signal open:
1. Check terminals at the ECM vehicle harness connector (both the ECM and harness side)
for bent, corroded, and unseated pins or sockets. See Figure 11-5.
[a] If the terminals and connectors are damaged, repair the terminals, connectors, or
both. Refer to section 11.3.12.
All information subject to change without notice.
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION
11-9
