66.3 TROUBLESHOOTING FLASH CODE 66
The following procedure will troubleshoot Flash Code 66.
The following procedure will enable you to determine the failure.
1. Code s 076 0, knock level above normal range - A Failure Mode Identifier (FMI) of
0 is used to advise the user that the knock level is too high to allow the electronics to
compensate for it. Troubleshoot this as a mechanical problem.
2. Code s 076 - 7, knock level torque reduction - An FMI of 1 is used to advise the user
the loss of engine power is due to the engine electronics trying to adjust the fueling to
further reduce the knock level. Clear the code and retest. If the code continues to occur,
contact Detroit Diesel Technical Service.
3. For code s 076-3, knock sensor input voltage high, refer to section 66.3.2.
4. For code s 076-4, knock sensor input voltage low; refer to section 66.3.3.
Check Signal to Noise Enhancement Filter Module / Knock Sensor
Perform the following steps to check the Signal to Noise Enhancement Filter (SNEF) and knock
1. Unplug the SNEF module.
2. Turn ignition ON.
3. Plug in DDR. Read codes.
[a] If code s 076-4 is logged, refer to section 66.3.4.
[b] If code s 076-3 is logged, refer to section 66.3.5.
Check for Open
Perform the following steps to check for an open:
1. Unplug SNEF.
2. Install a jumper wire between cavity B and E.
3. Turn ignition ON.
4. Plug in DDR. Read codes.
[a] If code s 076-3 is logged, refer to section 66.3.4.
[b] If code s 076-4 is logged, refer to section 66.3.7.
All information subject to change without notice.
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