ELECTRICAL SYSTEM TESTS, INSPECTIONS, AND ADJUSTMENTS - CONTINUED
ENGINE SPEED/TIMING SENSOR CIRCUIT TEST - CONTINUED
Check for diagnostic codes.
Place battery disconnect switch in ON position (TM 5-3805-291-10).
Start engine and run engine. Problem may occur when engine is at any operating temperature. However, problem is
more likely to occur when engine is at normal operating temperature.
If engine will not start, monitor engine speed on ET while engine is being cranked. ET may need to be powered
from another battery while engine is being cranked. This is done so that ET will not reset.
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Upon initial cranking, status for engine speed may indicate that engine speed signal is abnormal. This mes-
sage should be replaced with an engine speed once ECM is able to calculate a speed from signal.
Wait at least 30 seconds for activation of diagnostic codes. Look for these codes on ET:
320-02 Speed/Timing Sensor Loss of Signal
320-11 Speed/Timing Sensor mechanical failure
342-02 Loss of Secondary Engine Speed signal
342-11 Secondary Engine Speed Sensor mechanical failure
Expected Results. One or more diagnostic codes listed above are logged or active.
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If engine will not start and ET displayed 0 rpm during cranking, select "No Engine rpm".
No engine rpm - Engine rpm is not indicated on ET. Proceed to step 2.
Active code or logged code - There is an active diagnostic code or a logged diagnostic code for an engine
speed/timing sensor. Proceed to step 2.
Inspect sensor assembly.
Place battery disconnect switch in OFF position (TM 5-3805-291-10).
Remove engine speed/timing sensor(s) with active diagnostic code from engine (WP 0076 00 and/or WP 0078 00).
Ensure one O-ring seal is installed on each sensor, and ensure O-ring seals are free of damage.
Expected Results. Two undamaged O-ring seals are properly installed. Brackets are not bent. Flange for each sen-
sor can be flush against housing.
If results are OK, two undamaged O-ring seals are properly installed. Brackets are not bent. Flange for
each sensor can be flush against housing. Proceed to step 3.
If results are not OK, sensor assembly has a mechanical problem. Replace sensor (WP 0076 00 or WP
0078 00). Verify problem is resolved.