DDEC TROUBLESHOOTING
31.3 TROUBLESHOOTING FLASH CODE 31
The following procedure will troubleshoot Flash Code 31.
31.3.1
Check Configuration
Perform the following steps to check configuration.
1. If the unit has engine brakes, refer to section 31.3.2.
2. If the unit does not have engine brakes, the ECM is configured for engine brakes and
shouldn't be. Contact DDC with the engine serial number to have the data changed.
Reprogram the ECM after the change. Refer to section 31.3.10.
31.3.2
Determine Failure Mode
Perform the following steps to determine failure mode.
1. Turn vehicle ignition ON.
2. Plug the diagnostic data reader (DDR) into the diagnostic data link (DDL) connector.
3. Read SAE code (051 or 052).
[a] If the reading is FMI=3, there is an open. Refer to section 31.3.3.
[b] If the reading is FMI=4, there is a short to ground. Refer to section 31.3.7.
31.3.3
Determine Engine Type
Perform the following steps to determine engine type.
1. Is this a Series 55 engine?
[a] If yes, reprogram the ECM. Then, refer to section 31.3.10.
[b] If no, refer to section 31.3.4.
31.3.4
Check for Open
Perform the following steps to check for open.
1. Turn vehicle ignition OFF.
2. Disconnect 2-pin connector pigtail from engine brake harness.
3. Disconnect 30-pin engine harness connector.
4. Install a jumper wire between pins #561 and #562, ECM side.
5. Measure resistance between S3 (#561) and T3 (#562) of the engine harness connector.
[a] If measured resistance is less than 50
, refer to section 31.3.5.
All information subject to change without notice.
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION
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