Perkins NJ Series Troubleshooting Manual page 157

SENR9982-01
G. Install the jumper wire on the P2 connector.
Insert the jumper wire between the terminal
for the suspect sensor signal and the common
connection for the engine's pressure sensor.
Use Perkins EST to verify that there is a Voltage
Above Normal diagnostic code.
Expected Result:
Voltage Below Normal diagnostic codes and Voltage
Above Normal diagnostic codes were active.
Results:
• OK – The ECM is operating correctly. Proceed to
Test Step 9.
• Not OK – One of the following conditions exists:
The Voltage Below Normal diagnostic code is not
active when the harness is disconnected. The
Voltage Above Normal diagnostic code is not active
when the jumper wire is installed.
Repair: Perform the following repair:
1. Temporarily connect a test ECM.
Note: The test ECM should have the same values
and the same parameters as the suspect ECM.
2. Remove all jumpers and replace all connectors.
3. Use Perkins EST to recheck the system for
active diagnostic codes.
4. Repeat the Test Step.
5. If the fault is resolved with the test ECM,
reconnect the suspect ECM.
6. If the fault returns with the suspect ECM,
replace the ECM.
7. 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 9. Bypass the Harness Wiring
Between the ECM and the Sensor
Connector.
A. Turn the keyswitch to the OFF position.
B. Disconnect the P2 connector and disconnect the
connector from the suspect sensor.
C. Remove the sensor signal wire from the P2
connector.
D. Remove the signal wire (terminal 3) from the
sensor connector on the engine harness.
E. Fabricate a jumper wire that is long enough to
reach from the ECM to the sensor connector or
use an engine sensor harness bypass with 3
terminals.
Note: If an engine sensor harness bypass is being
made, crimp a socket on one end in order to connect
to the ECM. Crimp either a pin or a socket on the
other end, as required.
F. Insert the one end of the engine sensor harness
bypass into P2 connector on the engine harness.
Insert the other end of the engine sensor harness
bypass into the sensor connector of the engine
harness.
G. Reconnect the P2 connector and the sensor
connector.
H. Turn the keyswitch to the ON position.
I. Use the Perkins EST to monitor the "Active
Diagnostic Code" screen for either the open circuit
diagnostic code for the sensor or the short circuit
diagnostic code for the sensor.
Expected Result:
The diagnostic code disappears when the jumper or
the bypass is installed.
Results:
•
OK – There is a fault in the wiring harness.
Repair: Perform the following repair:
1. Repair the faulty harness or replace the faulty
harness.
2. Clear all diagnostic codes.
3. Use the electronic service tool in order to clear
all logged diagnostic codes and then verify that
the repair eliminates the fault.
STOP.
• Not OK – The most likely cause is an intermittent
fault.
Repair: By using the Perkins EST, perform a
"Wiggle Test". If no fault is found, restart this
procedure and carefully perform each step.
STOP.
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Troubleshooting Section