Perkins 1106D Troubleshooting Manual page 136

136
Troubleshooting Section
Note: When the ECM automatically calibrates new
duty cycle values for the low idle throttle position and
the high idle throttle position, the ECM assumes 22
percent duty cycle at low idle and 75 percent duty
cycle at high idle. As a result, you may notice that
the throttle position status reaches 100 percent well
before the throttle pedal is fully depressed. This is
normal. After some cycling of the throttle pedal to the
high idle position, the ECM will adjust the calibration
automatically. The ECM will adjust the calibration
automatically provided that the high idle stop position
is within the 75 to 90 percent duty cycle range, and
the low idle is in the 10 to 22 percent duty cycle
range. During normal operation, you may also notice
that more movement of the throttle pedal is required
for the throttle position status to increase above
three percent. You may also observe that the status
reaches the 100 percent value prior to the limit of the
high idle position. This is done in order to ensure
that the throttle reaches these two critical points for
engine operation.
Expected Result:
Result 1 Diagnostic code 91-08 is active.
Result 2 Diagnostic code 41-03 is active.
Result 3 There are no active diagnostic codes that
are related to the digital throttle pedal position sensor
circuit at this time, but a fault is suspected with
operation of the digital throttle position sensor circuit.
Results:
•
Result 1 – Proceed to Test Step 3.
•
Result 2 – Proceed to Test Step 5.
•
Result 3 – Proceed to Test Step 3.
Test Step 3. Check the Duty Cycle of the
Digital Throttle Position Sensor
A. Verify that the keyswitch is in the ON position.
B. Monitor the duty cycle of the throttle sensor on the
Perkins EST throttle display screen.
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 – The digital throttle position sensor is
operating correctly. Proceed to Test Step 6.
•
Not OK – The digital throttle position sensor circuit
is not operating correctly. Proceed to Test Step 4.
Test Step 4. Check the Supply Voltage at
the Digital Throttle Position Sensor
A. Turn the keyswitch to the OFF position.
B. Install a breakout "T" with 3 terminals at the digital
throttle position sensor connector J403/P403.
C. Turn the keyswitch to the ON position.
D. Measure the voltage at terminal "A" (+8 V) with
reference to terminal "B" (digital throttle position
sensor ground).
Expected Result:
The measured voltage is between 7.5 VDC and 8.5
VDC for the digital throttle position sensor.
Results:
•
OK – Proceed to Test Step 8.
•
Not OK – The sensor is not receiving the correct
voltage. Proceed to Test Step 5.
Test Step 5. Monitor Perkins Electronic
Service Tool (EST) while the Digital
Throttle Position Sensor is Being
Disconnected
A. Access the active diagnostic code screen on
Perkins EST. Ensure that one of the following
diagnostic code is active before proceeding:
•
41-03
•
41-04
B. Monitor the active diagnostic code screen while
the digital throttle position sensor is being
disconnected and reconnected.
Expected Result:
One of the following diagnostic codes is still active
after the digital throttle position sensor has been
disconnected:
•
41-03
•
41-04
Results:
•
OK – Ensure that the digital throttle position
sensor has been reconnected before continuing.
Proceed to Test Step 7.
SENR9982