54 Section 3 Decision-Makerr 3+ Troubleshooting TP-6356 4/12
TP-5353-6
1. AC fuse terminal block
1
Figure 3-20 AC Fuse Terminal Block
3-187
1. (+) Connection—P4-6
2. (--) Connection—P4-1
1
2
Figure 3-21 Checking Input Voltage to
Lamp Circuit Board
Overcrank Lamp
Open speed sensor circuit? Check continuity of wire 2
(black), wire 16 (white), and wire 24 (red) between P1
connector and speed sensor. Check for 10-12 volts DC
across speed sensor (+) positive terminal and (--)
negative terminals. Check wire 16 for 3--6 volts DC,
and wire 24 for 8--10 volts DC while unit is
cranking/running. Does test check out okay?
Excessive speed sensor air gap?
Engine starts and runs, but overcrank lamp flashes.
Note: The overcrank lamp will flash if speed sensor
signal is absent longer than one second.
Adjust speed sensor air gap to
specifications. See Section 1.
Is speed sensor
defective? See
speed sensor test in
Section 8.20.
Repair circuit.
No
Yes
Yes
No
Replace speed
sensor.
Yes
Replace main
control board.
No