Perkins NJ Series Troubleshooting Manual page 156

156
Troubleshooting Section
C. Refer to Troubleshooting, "Electrical Connectors
- Inspect".
D. If the short circuit diagnostic code reappears, the
sensor or the sensor connector has a fault.
a. Temporarily connect a new sensor to the
harness, but do not install the new sensor in
the engine.
E. Use the Perkins EST to check for a short circuit
diagnostic code. The new sensor should be
connected to the harness at this time.
Expected Result:
The short circuit diagnostic code is not present when
a new sensor is connected.
Results:
• OK – 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 – Repair the engine harness connector.
Use the Perkins EST to clear the logged diagnostic
codes. STOP.
Test Step 7. Create a Short Circuit
Between the Signal and the Common
Terminals at the Engine Harness
Connector.
A. Turn the keyswitch to the ON position.
B. Fabricate a jumper wire 150 mm (6 inch) long.
Crimp a terminal to both ends of the wire.
C. Monitor the "Active Diagnostic Code" screen of
the Perkins EST before installing the jumper wire
and after installing the jumper wire.
D. Install the jumper on the engine harness
connector. Install one end of the jumper at the
sensor signal (terminal 3). Install the other end
of the jumper at the common connection for
the pressure sensor (terminal 2). Wait at least
30 seconds for activation of the short circuit
diagnostic code.
Expected Result:
A short circuit diagnostic code is active when the
jumper is installed. An open circuit diagnostic code is
active when the jumper is removed.
Results:
• OK – The engine harness and the ECM are OK.
Repair: Perform the following repair:
1. Temporarily connect the suspect sensor.
2. Use the Perkins EST to verify if the diagnostic
code remains active.
3. If the diagnostic code is active replace the
sensor.
4. Use the electronic service tool in order to clear
all logged diagnostic codes and then verify that
the repair eliminated the fault.
STOP.
• Not OK – The open circuit diagnostic code
remains active when the jumper is installed. The
most probable location for the open circuit is in the
common wire for the sensor, or in the sensor signal
wire of the engine harness between the ECM and
the sensor. Remove the jumper. Proceed to Test
Step 8.
Test Step 8. Check the Operation of the
ECM by Creating Open and Short Circuits
at the ECM Connector.
A. Turn the keyswitch to the OFF position.
B. Disconnect connector P2 from the ECM.
Thoroughly inspect both halves of the connector
for signs of corrosion or moisture. Refer to
Troubleshooting, "Electrical Connectors - Inspect".
C. Reconnect P2 connector.
D. Turn the keyswitch to the ON position. Use
Perkins EST in order to monitor the "Active
Diagnostic Code" screen. Wait at least 10 seconds
for activation of the code.
An open circuit diagnostic code should be active
for the suspect sensor.
Note: When the P2connector is disconnected, all of
the open circuit 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.
SENR9982-01