Perkins NJ Series Troubleshooting Manual page 170

170
Troubleshooting Section
• Not OK – The Voltage Above Normal diagnostic
code remains active with the jumper in place. The
most probable location for the open circuit is in the
sensor common or the sensor signal wire in the
engine harness between the ECM and the sensor.
Remove the jumper. Proceed to Test Step 6.
Test Step 6. Check The Operation Of The
ECM By Creating An Open And A Short
Circuit At The ECM Connector.
A. Turn the keyswitch to the OFF position.
B. Disconnect the P2 connector.
C. Thoroughly inspect both halves of the connector
for signs of corrosion or moisture. Refer to
Troubleshooting, "Electrical Connectors - Inspect".
D. Turn the keyswitch to the ON position. Use the
Perkins EST in order to monitor the "Active
Diagnostic Code" screen. Wait at least 10 seconds
for activation of the code.
An Voltage Above Normal diagnostic code should
be active for the suspect sensor.
Note: When P2 is disconnected, all of the Voltage
Above Normal diagnostic codes for the pressure
sensors and temperature sensors will be active.
This is normal. Disregard the diagnostic codes for
the pressure sensors and the temperature sensors
that are not suspect. Direct your attention to the
diagnostic codes for the suspect sensors only.
E. Turn the keyswitch to the OFF position.
F. Fabricate a jumper wire 150 mm (6 inch) long.
Crimp a terminal to both ends of the wire.
G. Monitor the "Active Diagnostic Code" screen on
the Perkins EST before installing the jumper wire
and after installing the jumper wire.
H. Remove the suspect sensor signal pin from the
P2 connector, either pin P2:42 for the intake
manifold temperature sensor or P2:43 for the
coolant temperature sensor. Remove P2:37
sensor common connector. Install the jumper on
the P2 connector. Install one end of the jumper
at the suspect sensor signal pin. Install the other
end of the jumper to P2:37 common connection
for the sensors. Reassemble the P2 connector to
the ECM. Use the Perkins EST in order to check
the diagnostic codes. Wait at least 10 seconds for
activation of the Voltage Below Normal diagnostic
code.
Note: The Voltage Above Normal diagnostic code for
the temperature sensor that is not suspect should
become active when the sensor common connection
is removed from the P2 connector. This code can be
disregarded.
Expected Result:
A Voltage Below Normal diagnostic code is active
when the jumper is installed. An Voltage Above
Normal diagnostic code is active when the jumper
is removed.
Results:
• OK – Proceed to test step 7.
•
Not OK
Repair: The ECM does not operate correctly.
1. Temporarily connect a test ECM.
Note: The test ECM should be programmed with the
correct software. All parameters should be set to the
same value of the suspect ECM.
2. Remove all jumpers and reconnect all
connectors.
3. If the fault is eliminated with the test ECM,
reconnect the suspect ECM and verify that the
fault returns.
4. If the fault returns replace the suspect ECM.
Refer to Troubleshooting, "Replacing the ECM".
5. 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 7. Bypass The Harness Wiring
Between The ECM And The Sensor
Connector.
A. Turn the keyswitch to the OFF position.
B. Disconnect the P2 connector on the ECM harness,
and the suspect sensor connector.
C. Remove the sensor signal wire from the P2
connector.
D. Remove the signal wire (terminal 1) 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 with
sockets on both ends.
SENR9982-01