DDEC TROUBLESHOOTING
1. Turn ignition OFF.
2. Unplug engine sensor harness.
3. Install a jumper between wire cavity A and F of the throttle actuator connector.
4. Measure resistance between cavity R1 and S3, then R1 and T3 at the engine sensor harness.
[a] If both readings are less than 1,000
refer to section 65.3.5.
[b] If either reading is greater than 1,000 , it indicates the #561 or #562 wire is open.
Repair or replace the wire and refer to section 65.3.8.
65.3.5
Check PWM #2
Perform the following steps to check PWM #2:
1. Move jumper to cavities E and F at the throttle activator.
2. Measure resistance between cavities R1 and Y1 of the engine sensor harness.
[a] If the measurement is less than 1,000 , refer to section 65.3.6.
[b] If the measurement is greater than 1,000 , the wire #909 (PWM#2) is open. Repair
or replace the wire and refer to section 65.3.8.
65.3.6
Check Connectors
Perform the following steps to check the connectors.
1. Check both connectors for damaged, bent or broken pins or terminals.
[a] If the connectors are not damaged, refer to section 65.3.7.
[b] If the connectors are damaged, repair or replace the connectors.
Refer to section 65.3.8.
65.3.7
Check for Short
Perform the following steps to check for a short.
1. Remove jumper.
2. Measure resistance between cavity Y1 and R1 on the engine sensor harness.
3. Measure resistance between Y1 and T3 of the engine sensor harness.
[a] If the measured resistance is less than 1,000 , the wires are shorted to each other.
Repair or replace the wires and refer to section 65.3.8.
[b] If the measured resistance is greater than 1,000 , troubleshooting is complete.
Review this section or contact Detroit Diesel Technical Service to replace the
actuator. Refer to section 65.3.8.
All information subject to change without notice.
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION
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