DDEC TROUBLESHOOTING
2. Measure resistance between socket D of the 5-way power harness connector to the
following sockets on the injector harness connector: A, B, C, D, E, G, H, J, K and L.
[a] If the resistance measurement is greater than or equal to 10,000
or open on all
readings, refer to section 10.2.13.
[b] If the resistance measurement is less than 10,000
on any reading, there is a short
to ground on the wire where resistance was less than 10,000 . Repair the short
and refer to section 10.2.27.
10.2.13 Injector Drive Pulses
Perform the following steps to check the injector drive pulses:
1. Turn ignition OFF.
2. Reconnect all ECM connectors. See Figure 10-1.
3. Remove rocker covers.
4. Disconnect return wire #619 or #620 from one injector.
5. Place a 6-volt test light across the previously disconnected injector return side and a
good ground.
6. Crank engine and note the test light to see if it lights (flashes).
7. Reconnect the return wire.
8. Repeat the above procedure with all other injectors until all have been tested or until
one test fails.
[a] If all tests pass, the problem does not appear to be in the DDEC system.
[b] If all tests do not pass and the test light is flashing for one or more tests, check for
proper parts (e.g. bull gear) then try a test ECM. Refer to section 10.2.27.
All information subject to change without notice.
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION
10-7
