C11 and C15 Engines for Caterpillar Built Machines Caterpillar

Use this procedure to troubleshoot the system when one of the following diagnostic codes is active or easily repeated:

• 262-03 5 Volt Sensor DC Power Supply short to +batt

• 262-04 5 Volt Sensor DC Power Supply short to ground

• 100-10 Engine Oil Pressure Sensor abnormal rate of chang

The Electronic Control Module (ECM) supplies a regulated voltage of 5.0 ± 0.16 VDC to the following sensors:

• Intake manifold (boost) pressure sensor

• Engine oil pressure sensor

• Fuel pressure sensor

• Atmospheric pressure sensor

• Right turbocharger inlet pressure sensor

The supply for the +5 V engine pressure sensor is routed from the ECM to terminal A of each pressure sensor connector. The sensor common from the ECM connector goes to terminal B of each sensor connector. The sensor supply is output short circuit protected. A short circuit to the battery will not damage the circuit inside the ECM.

Note: The sensors are not protected from overvoltage. A short from the supply line to the +Battery may damage the sensors. If the CID-FMI 262-03 is logged, it is possible that all of the sensors have been damaged. Repair the sensor supply and check for any "ACTIVE" sensor diagnostic codes in order to determine if a sensor has failed.

The +5 V diagnostic code is probably caused by a short circuit to ground or a short circuit to another voltage source in the harness.

Illustration 1	g01261783
Schematic

Illustration 2	g01204484
P2 ECM connector (P2-15) Intake manifold (boost) pressure sensor (P2-17) Sensor return (P2-28) Engine oil pressure sensor (P2-40) Fuel pressure sensor (P2-57) Atmospheric pressure sensor (P2-72) Sensor supply

Illustration 3	g01259757
Terminal locations at the P1 ECM connector (P1-15) Turbocharger inlet pressure sensor

Illustration 4	g01142382
Locations of the pressure sensors (typical left side engine view) (1) Intake manifold (boost) pressure sensor (2) Atmospheric pressure sensor (3) Engine oil pressure sensor (4) Fuel pressure sensor (5) J2/P2 ECM connectors (6) J1/P1 ECM connectors

Illustration 5	g01142856
Typical air filter assembly (7) Turbocharger inlet pressure sensor

Illustration 6	g01159881
Terminal locations at the sensor connector (A) Sensor supply (B) Sensor return (C) Sensor signal

Test Step 1. Inspect Electrical Connectors and Wiring

1. Remove the electrical power from the ECM.

2. Thoroughly inspect connectors (5) and (6). Also, thoroughly inspect the connectors for sensors (1), (2), (3), (4), and (7). Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".

3. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and on each of the wires in the pressure sensor connectors.

4. Check the allen head screw for each of the ECM connectors and the machine connectors for the proper torque. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".

5. Check the harness and wiring for abrasions and for pinch points from each of the pressure sensors back to the ECM.

Expected Result:

All connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion or of pinch points.

Results:

• OK - The harness and connectors appear to be OK. Proceed to Test Step 2.

• Not OK - There is a problem with the connectors and/or wiring.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals for each of the connectors are properly in place and ensure that the connectors are completely coupled. Verify that the repair eliminates the problem.

  STOP

Test Step 2. Check for Active Diagnostic Codes

1. Connect Caterpillar Electronic Technician (ET) to the service tool connector.

2. Restore the electrical power to the ECM.

   Note: Wait at least 30 seconds in order for the diagnostic codes to become active.

3. Monitor Cat ET for an active 262-03 code, an active 262-04 code, or an active 100-10 code.

4. Remove the electrical power from the ECM.

Expected Result:

No diagnostic codes are active.

Results:

• OK - No diagnostic codes are active.

  Repair: If the problem is intermittent refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".

  STOP

• Not OK - There is an active -03 code, an active -04 code, or an active -10 code at this time: Proceed to Test Step 3.

Test Step 3. Disconnect the Pressure Sensors and Check for Active Diagnostic Codes

1. Restore the electrical power to the ECM.

2. Monitor the active diagnostic code screen on Cat ET while you disconnect each pressure sensor connector. Check for an active diagnostic code.

   Note: Wait at least 30 seconds in order for the diagnostic codes to become active.

   1. Disconnect the following sensors one at a time:

      • Engine oil pressure sensor

      • Intake manifold (boost) pressure sensor

      • Fuel pressure sensor

      • Atmospheric pressure sensor

      • Turbocharger Inlet pressure sensor

3. Remove the electrical power from the ECM.

Expected Result:

The diagnostic code deactivates when a particular sensor is disconnected.

Results:

• OK - The -03 code, the -04 code, or the -10 diagnostic code deactivates when a particular sensor is disconnected.

  Repair: Connect the suspect sensor. If the code returns, replace the sensor. Connect all of the connectors. Verify that the problem is resolved.

  STOP

• Not OK - The -03 code, the -04 code, or the -10 diagnostic code remains active after all of the sensors are disconnected. Leave the sensors disconnected. The sensors are not the cause of the diagnostic code. Proceed to Test Step 4.

Test Step 4. Check the Supply Voltages at the ECM

1. Disconnect the J2/P2 ECM connector.

2. Fabricate four jumper wires that are long enough to be used to measure the supply voltage at the ECM connectors. Crimp connector sockets to one end of each jumper wire.

3. Remove the wires from terminal locations P2-72 (sensor supply) and P2-17 (sensor return). Install a jumper wire into each of these terminal locations.

4. Connect the J2/P2 ECM connector.

5. Restore the electrical power to the ECM.

6. Measure the voltage between the jumper wire in P2-72 (sensor supply) and the jumper wire in P2-17 (sensor return).

7. Remove the electrical power from the ECM.

Expected Result:

The voltage measurement is 5.0 ± 0.2 VDC.

Results:

• OK - The voltage measurement is 5.0 ± 0.2 VDC. The ECM is operating correctly.

  Repair: The supply wire is shorted to another wire in the harness or the supply wire is shorted to engine ground. Repair the wiring and/or the connector. Replace parts, if necessary. Verify that the problem is resolved.

  STOP

• Not OK - The voltage measurement is not 5.0 ± 0.2 VDC.

  Repair: Replace the ECM. Refer to electronic troubleshooting Troubleshooting, "Replacing the ECM".

  STOP