0341135 JOHNSON PLATE, Frame, rear, 30

Illustration 1 g00902820
+5 V supply circuit
Illustration 2 g00898567
P2 ECM connector (wire side)
Illustration 3 g00898570
P2 ECM connector (ECM side)
Illustration 4 g00810608
Sensor connectorTest Step 1. Disconnect the ECM Connectors and Check for Active Diagnostic Codes
Turn the keyswitch to the OFF position.
Connect the Caterpillar Electronic Technician (Cat ET) to the service tool connector.
Disconnect the P2 ECM connector from the ECM.
Check the connectors for corrosion and for moisture. Make repairs, if necessary.
Turn the keyswitch to the ON position.
Check for active diagnostic codes on Cat ET.Note: Several diagnostic codes will be active. Look for 5 Volt diagnostic codes and clear all of the other codes after this test.Expected Result:The 5 volt diagnostic codes are not active. An open circuit diagnostic code is active for all of the engine pressure sensors.Results:
OK - The 5 volt diagnostic codes are not active.Repair: Reconnect the P2 ECM connector. Proceed to Test Step 2.
Not OK - A 262-03 code or a 262-04 code is still active.Repair: Connect a test ECM.If the test ECM fixes the problem, reconnect the suspect ECM.If the problem returns, permanently install the new ECM.Verify that the repair eliminates the problem.STOPTest Step 2. Disconnect the Sensors
Turn the keyswitch to the ON position.
Monitor the active diagnostic code screen on Cat ET and disconnect the pressure sensors one at a time. Wait for 30 seconds after each pressure sensor is disconnected.The original code may still be active. If the code was due to an intermittent problem with the J2/P2 ECM connector the code may not be active.Note: The 5 volt diagnostic code will become inactive if a particular pressure sensor is the cause of the code. Open circuit diagnostic codes will become active for disconnected sensors. Clear the open circuit diagnostic codes after this test.Expected Result:The 5 volt diagnostic code is still active when all of the pressure sensors are disconnected.Note: Leave all pressure sensors disconnected. Determine whether 262-03 or 262-04 is active.Results:
Yes 262-03 is active. - Proceed to Test Step 3.
Yes 262-04 is active - Proceed to Test Step 5.
No - The 5 volt diagnostic code disappears when a particular pressure sensor is disconnected.Repair: Reconnect all of the pressure sensors except the suspect sensor. Connect a pressure sensor that is known to be good. Check for the 5 Volt diagnostic code. Reconnect the suspect sensor. If the 5 Volt diagnostic code returns, remove the suspect sensor and replace the sensor with a sensor that is known to be good.STOPTest Step 3. Measure the 5 Volt Supply to the Sensor
Turn the keyswitch to the ON position.Note: Verify that all of the pressure sensors are disconnected.
Measure the voltage between terminal A (+5V) and chassis ground from the engine harness connector for each pressure sensor.Expected Result:The voltage is 5.0 0.16 VDC.Results:
OK - The 5 volt supply is within the range. Proceed to Test Step 4.
Not OK - The voltage is greater than 5.16 volts.Repair: Check the 5 volt supply wire for a short to a higher voltage source.Repair the 5 volt supply wire or replace the 5 volt supply wire.Verify that the repair eliminates the problem.STOPTest Step 4. Check the Common Wire
Turn the keyswitch to the ON position.
Measure the voltage between terminal A (+5V) and terminal B (Common) from the engine harness connector for each pressure sensor.
While the voltage is monitored, perform a 45 N (10 lb) pull test on the common wires for the 5 volt supply.
P2:3 (Common)Expected Result:The voltage is 5.0 0.16 VDC.Results:
OK - The voltage is within the range.Repair: If the problem is intermittent, refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - The voltage is not within the range.Repair: Inspect the common wire for an open circuit.Repair the common wire or replace the common wire.Verify that the repair eliminates the problem.STOPTest Step 5. Check the Resistance of the Harness
Turn the keyswitch to the OFF position.
Verify that all of the sensors are disconnected.
Measure the resistance between terminal A (+5V) and terminal B (Common) from the engine harness connector of each pressure sensor.
Measure the resistance between terminal A (+5V) and the ground connection from the engine harness connector.Expected Result:The resistance is greater than 20,000 Ohms, or "OL" is displayed on the multimeter.Results:
OK - The 5 volt supply and the pressure sensor common are not shorted.Repair: The problem is intermittent. Refer to Troubleshooting, "Electrical Connectors - Inspect".Verify that the repair eliminates the problem.STOP
Not OK - The 5 volt supply is shorted to the pressure sensor common or ground.Repair: Locate the short.Repair the wiring or replace the wiring.Verify that the repair eliminates the problem.STOP