Perkins NJ Series Troubleshooting Manual page 144

144
Troubleshooting Section
• For 12 volt systems, the voltage should be
between 11.0 VDC and 13.5 VDC.
•
For 24 volt systems, the voltage should be
between 22.0 VDC and 27.0 VDC.
If the battery voltage is correct, temporarily connect
a test ECM. Use Perkins EST to verify that the
active diagnostic code is resolved. If the fault is
corrected with the test ECM, reconnect the suspect
ECM. Verify that the active diagnostic code returns.
If the active diagnostic code returns with the
suspect ECM, replace the ECM.
STOP.
•
Not OK
Repair: Perform the following repair:
There is a fault in the harness between the ECM
and the digital throttle position sensor. While
active diagnostic codes are being monitored,
connect the removed wires one at a time in order
to verify that the active diagnostic codes reappear.
ReplaceP1:33. Replace P1:43 (digital throttle
position sensor ground 8 Volt). This procedure is
used to find the wire that is causing the fault. Repair
the harness or replace the harness, as required.
Use the electronic service tool in order to clear all
logged diagnostic codes and then verify that the
repair eliminates the fault.
STOP.
Test Step 8. Check the Duty Cycle of the
Accelerator Pedal Position Sensor at the
Sensor
Note: Performing certain steps within this procedure
requires the use of a multimeter that is capable of
measuring a PWM duty cycle.
A. Turn the keyswitch to the OFF position.
B. Remove the signal wire for the digital throttle
position sensor (terminal "C") from P403. Refer to
illustration 42.
C. Install a breakout "T" with three terminals at
the digital throttle position sensor connector
J403/P403.
D. Connect the multimeter probes to terminal "B"
(digital throttle position sensor signal) and terminal
"B" (digital throttle position sensor ground) of the
breakout T.
E. Turn the keyswitch to the ON position.
F. While the duty cycle is being monitored on the
multimeter, depress the throttle pedal and release
the throttle pedal.
Expected Result:
The duty cycle is between 10 and 22 percent with the
throttle pedal assembly in the low idle position, and
the duty cycle is between 75 and 90 percent with the
throttle pedal assembly in the high idle position.
Results:
• OK – Reinsert the wire (terminal "C") into the
harness connector of the digital throttle position
sensor. The digital throttle position sensor is
working correctly. Proceed to Test Step 9.
• Not OK – Leave the PWM probe connected to the
breakout "T". Insert the wire (terminal "C") into the
machine harness connector. The throttle pedal
assembly is faulty. Proceed to Test Step 10.
Test Step 9. Check the Duty Cycle of the
Accelerator Pedal Position Sensor at the
ECM
Note: Performing certain steps within this procedure
requires the use of a multimeter that is capable of
measuring a PWM duty cycle.
A. Turn the keyswitch to the OFF position.
B. Remove the P1:53. Disconnect the P1 connector
in order to remove the terminal for the signal input
of the digital throttle position sensor signal.
C. Connect the multimeter probes between the
removed wire and the P1:33 (digital throttle
position sensor ground).
D. Reconnect the P1 connector to the ECM.
E. Turn the keyswitch to the ON position.
F. Use the multimeter in order to display the
duty cycle output of the digital throttle position
sensor. While the duty cycle output of the digital
throttle position sensor is being monitored on the
multimeter, move the throttle assembly from the
low idle position to the high idle position. Record
the results.
G. Turn the keyswitch to the OFF position.
H. Remove the P1 connector from the ECM.
I. Install the pin P1:53.
J. Connect the P1 connector to the ECM.
SENR9982-01