87.3
TROUBLESHOOTING FLASH CODE 87
87.3.4
Check for Short to Return
Perform the following steps to check for a short.
1. Turn ignition OFF.
2. Remove jumper wire.
3. Remove vehicle interface harness connector (30-pin).
4. Turn ignition ON.
5. Measure resistance between C3 (#952) and D3 (#749).
[a] If the measured resistance is less than 1,000 , the wires are shorted to each other.
Replace the harness.
[b] If the measured resistance is greater than 1,000 , refer to section 87.3.5.
87.3.5
Check for Short to Battery (-)
Perform the following steps to check for a short to the battery (-).
1. Measure resistance between D3 (#749) and battery ground.
[a] If the measured resistance is less than 1,000 , the #749 wire is shorted to the battery.
Replace the harness and refer to section 87.3.7.
[b] If the measured resistance is greater than 1,000 , refer to section 87.3.6.
87.3.6
Check for 5 Volt Open
Perform the following steps to check for a 5 volt open.
1. Plug in the 30-pin connector for the vehicle sensor harness.
2. Turn ignition ON.
3. Measure voltage between cavity B (#952) and A (#916) of the transducer connector.
[a] If the measurement is less than 4.5 volts, wire #916 is open. Repair the open or
replace the harness. Refer to section 87.3.7.
[b] If the measurement is between 4.5 and 5.5 volts, the signal wire (#749) is open.
Repair the wire and refer to section 87.3.7.
87.3.7
Verify Repairs
Perform the following steps to verify repairs.
1. Plug in all connectors.
2. Start and run the engine.
3. Plug in DDR and read the codes.
[a] If no codes are logged, troubleshooting is complete.
All information subject to change without notice.
87-6
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION
