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Copyright 2017 Cummins Inc.
RACK POSITION FAULT/TEST
PROCEDURE
The rack position fault/test procedure is a trouble-
shooting tool for the Rack Position (260) warning
message. This test will isolate the fault to one of
these components; fuel pump, governor output
module (A38), or the PowerCommand control.
Use a calibrated RMS multimeter for accurate mea-
surements. Fluke models 87 or 8060A are good
choices.
1. Move the Run/Off/Auto switch to the Off posi-
tion.
2. At the engine interface board (A31), place a
jumper wire from A31-TP1 to A31-TP2 (see
Figure 3-4 for test point location).
3. Select RACK TEST from the Setup Menu
(page 5-17) to initiate the fuel rack test. This will
apply power to the governor output module.
4. Are A38 DS1 (RUN) and A38 DS2 (VCC) LEDs
on?
Yes: Go to next step.
No: Possible control problem. Remove jum-
ber wires (Step 2). Restart the generator
set and follow proper troubleshooting
procedure.
5. Are fuses A38 F1 and F2 blown?
Yes: Replace blown fuse and restart genera-
tor set.
No: Go to next step.
6. Move both racks from 0mm to 19mm from the
“POS MM” menu (see Setup Menu). Periodi-
cally read the DC voltages from J11-B (left
position voltage) to J11-A and J11-C (right
position voltage) to J11-A. (The J11 engine har-
ness connector is located at the bottom of the
accessory box.)
7. Do these voltages correspond to the voltage on
the display (
0.25 VDC)?
Yes: Test OK. Restart generator set and moni-
tor A38-DS5 (left position fault) and
A38-DS6 (right position fault).
No: Go to next step.
8. Are both left and right voltages out of toler-
ance?
Yes: Possible control or governor output mod-
ule problem. Check PWM signal (refer to
Step 4 of error Code 313 in Trouble-
shooting section).
No: Go to next step.
9. Move the racks to 0mm from the “POS MM”
menu. Monitor the position voltage of the side
that has the incorrect voltage.
10. Disconnect the fuel pump connector at the fuel
pump. Does the voltage rise up from approxi-
mately 1.3
0.25 VDC to 4.5 0.25 VDC ?
Yes: Replace defective fuel pump (refer to en-
gine service manual).
No: Replace defective governor output mod-
ule.
Engine Torque Adjustment procedure must be
performed after replacement of fuel pump or
governor output module. Refer to Section 5.
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