C-10 and C-15 Petroleum Engines Caterpillar

Use this procedure to troubleshoot any suspect problems with the +5 V sensor supply.

This procedure covers the following open circuit diagnostic codes and short circuit diagnostic codes:

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

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

The Electronic Control Module (ECM) supplies a regulated voltage of 5.0 ± 0.2 VDC to the following sensors:

• Atmospheric pressure sensor

• Auxiliary pressure sensor

• Engine oil pressure sensor

• Fuel pressure sensor

• Turbocharger outlet pressure sensor

The supply for the +5 V engine pressure sensors is routed from the ECM to terminal A of each pressure sensor connector. The sensor returns for the +5 V engine pressure sensors are routed from the ECM to terminal B of each pressure sensor connector.

Illustration 1	g01145390
Schematic for C-10 engines

Illustration 2	g01148768
Schematic for C-15 engines

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The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere.

Test Step 1. Inspect the Electrical Connectors and the Wiring

1. Turn the keyswitch to the OFF position.

2. Thoroughly inspect all connectors that are associated with the +5 V sensor supply for your engine. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
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   Illustration 3	g01145553
   C-10 engine (left side engine view) (1) Fuel pressure sensor (2) Atmospheric pressure sensor (3) Turbocharger outlet pressure sensor (4) P61 Customer connector (5) Engine oil pressure sensor (6) ECM (7) P2/J2 ECM connector (8) P1/J1 ECM connector

   1. For C-10 engines, inspect connectors (4), (7), and (8). Also inspect each of the connectors that are for sensors (1), (2), (3), and (5) .
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   Illustration 4	g01145557
   C-15 engine (left side engine view) (9) P61 Customer connector (10) Turbocharger outlet pressure sensor (11) Fuel pressure sensor (12) Atmospheric pressure sensor (13) Engine oil pressure sensor (14) ECM (15) P2/J2 ECM connector (16) P1/J1 ECM connector

   2. For C-15 engines, inspect connectors (9), (15), and (16). Also inspect each of the connectors that are for sensors (10), (11), (12), and (13) .

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Illustration 5	g01145450
P2 ECM connector for C-10 and C-15 engines (P2-2) +5 V Sensor supply (P2-3) Sensor return (P2-14) Atmospheric pressure sensor (P2-16) Fuel pressure sensor (P2-24) Engine oil pressure sensor (P2-40) Turbocharger outlet pressure sensor

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Illustration 6	g01145447
P1 ECM connector for C-10 and C-15 engines (P1-2) +5 V Sensor supply (P1-3) Sensor return (P1-15) Auxiliary pressure sensor

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Illustration 7	g01145543
P61 Customer connector (P61-2) +5 V Sensor supply (P61-3) Sensor return (P61-15) Auxiliary pressure sensor

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Illustration 8	g01123211
Connectors for the sensors (A) +5 V Sensor supply (B) Sensor return (C) Signal

3. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the +5 V sensor supply.

4. Check the torque of the allen head screw on the ECM connectors and the customer connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.

5. Check the harness and wiring for abrasion and for pinch points from the 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 and of pinch points.

Results:

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

• Not OK - The connectors and/or wiring are not OK.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals 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. Turn the keyswitch to the ON position.

3. Check for active diagnostic codes on Cat (ET). Record any active diagnostic codes.

   Note: Wait at least 15 seconds in order for the diagnostic codes to become active.

Expected Result:

No diagnostic codes are active.

Results:

• OK - No diagnostic codes are active.

  Repair: The problem may have been solved during the preceding inspection of the harness and connectors. The problem may be intermittent. If the problem is intermittent, refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".

  STOP

• Not OK - A 262-03 diagnostic code is active. Proceed to Test Step 3.

• Not OK - A 262-04 diagnostic code is active. Proceed to Test Step 4.

Test Step 3. Check the Voltage on the +5 V Supply Wire

1. Turn the keyswitch to the OFF position.

2. Disconnect all of the following +5 V pressure sensors at the sensor connector:
   • Fuel pressure sensor J209/P209

   • Engine oil pressure sensor J201/P201

   • Atmospheric pressure sensor J203/P203

   • Turbocharger outlet pressure sensor J200/P200

   • Auxiliary pressure sensor J220/P220

3. Turn the keyswitch to the ON position.

4. Measure the voltage between terminal A (+5 V supply) and terminal B (sensor return) at the sensor connectors.

Expected Result:

The voltage is 5.0 ± 0.2 VDC.

Results:

• OK - The voltage is correct.

  Repair: Replace all wires to the original configuration. Clear all diagnostic codes. Check for active diagnostic codes. If the problem is intermittent, refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".

  STOP

• Not OK - The voltage is incorrect. Proceed to Test Step 5.

Test Step 4. Disconnect the Pressure Sensors while you Monitor the Active Diagnostic Codes

1. Monitor the active diagnostic code screen on the Cat ET. Check and record any active diagnostic codes.

   Note: Wait at least 15 seconds in order for the diagnostic codes to become active.

2. Disconnect the following sensors one at a time:
   • Fuel pressure sensor J209/P209

   • Engine oil pressure sensor J201/P201

   • Atmospheric pressure sensor J203/P203

   • Turbocharger outlet pressure sensor J200/P200

   • Auxiliary pressure sensor J220/P220

   Note: An 03 open circuit diagnostic code will be generated for each sensor. Troubleshoot the original code. Delete the logged diagnostic codes when you are finished.

3. Wait for 15 seconds after each pressure sensor is disconnected. Check for an active diagnostic code on the Cat ET.

Expected Result:

The 262-04 diagnostic code deactivates. An 03 open circuit diagnostic code will be active for each sensor that was disconnected in the preceding steps.

Results:

• OK - The 262-04 diagnostic code deactivates. The diagnostic code is not active after a specific sensor is disconnected.

  Repair: Reconnect the sensor that is suspected of causing the problem. If the problem returns after the reconnection of the sensor, disconnect the sensor. If the problem disappears after the disconnection of the sensor, replace the sensor. Replace all wires to the original configuration. Clear all diagnostic codes. Verify that the repair eliminates the problem.

  STOP

• Not OK - The 262-04 diagnostic code stays active. Leave the sensors disconnected. Proceed to Test Step 5.

Test Step 5. Check for a Short Circuit at the ECM Connector

1. Turn the keyswitch to the OFF position.

2. Disconnect the J2/P2 ECM connector. Disconnect the J1/P1 ECM connector.

3. Leave the +5 V pressure sensors disconnected at the sensor connectors.

Note: Wiggle the harness during the following measurements in order to reveal any intermittent short condition.

4. Measure the resistance between ECM connector P2-2 (+5 V sensor supply) and every terminal on ECM connector P2 and ECM connector P1.

   1. Measure the resistance between the ECM connector P2-2 and the ECM ground strap.

5. Measure the resistance between the ECM connector P1-2 (+5 V sensor supply) and every terminal on ECM connector P1 and ECM connector P2.

   1. Measure the resistance between the ECM connector P1-2 and the ECM ground strap.

Expected Result:

The measurements indicate an open circuit.

Results:

• OK - An open circuit was indicated for each measurement. The resistance measurement does not indicate a short in the engine harness or a short to engine ground. Proceed to Test Step 6.

• Not OK - At least one of the measurements did not indicate an open circuit.

  Repair: The resistance measurement indicated a short between one or more wires or between a wire and engine ground. A wire for the sensor supply is shorted in the engine harness or to engine ground. Repair the wire or replace the harness. Clear all logged diagnostic codes. Replace all wires to the original configuration. Verify that the repair eliminates the problem.

  STOP

Test Step 6. Check the Harness for an Open Circuit

1. Install a wire jumper between terminal P2-2 (+5 V sensor supply) and terminal P2-3 (sensor return).

2. Install a wire jumper between terminal P1-2 (+5 V sensor supply) and terminal P1-3 (sensor return).

Note: Wiggle the harness during the following measurements in order to reveal any intermittent short condition.

3. Measure the resistance between terminal A (+5 V sensor supply) and terminal B (sensor return) at the pressure sensor connectors.

4. Remove the wire jumpers.

Expected Result:

The correct measurement is less than 5 Ohms.

Results:

• OK - The resistance is less than 5 Ohms. The resistance measurement does not indicate an open circuit in the engine harness. Proceed to Test Step 7.

• Not OK - The resistance is greater than 5 Ohms.

  Repair: There is excessive in the harness wiring. The +5 V supply wire or the sensor common has an open circuit in the harness. Repair the wires or replace the harness. Clear all logged diagnostic codes. Replace all wires to the original configuration. Verify that the repair eliminates the problem.

  STOP

Test Step 7. Check the +5 V Supply at the ECM

1. Remove terminal P2-2 (+5 V sensor supply) from the ECM connector. Install a wire jumper with socket terminals on both ends into P2-2.

2. Remove terminal P2-3 (sensor return) from the ECM connector. Install a wire jumper with socket terminals on both ends into P2-3.

3. Reconnect ECM connector J2/P2.

4. Remove terminal P1-2 (+5 V sensor supply) from the ECM connector. Install a wire jumper with socket terminals on both ends into P1-2.

5. Remove terminal P1-3 (sensor return) from the ECM connector. Install a wire jumper with socket terminals on both ends into P1-3.

6. Reconnect ECM connector J1/P1.

7. Turn the keyswitch to the ON position.

8. Measure the voltage between the wire jumper in P2-2 and the wire jumper in P2-3.

9. Measure the voltage between the wire jumper in P1-2 and the wire jumper that is in P1-3.

10. Turn the keyswitch to the OFF position.

11. Replace all wires to the original configuration.

Expected Result:

The voltage is 5.0 ± 0.2 VDC for both measurements.

Results:

• OK - The voltage is correct.

  Repair: Clear all diagnostic codes. The problem is most likely in a harness connector. If the problem is intermittent, refer to Troubleshooting, "Electrical Connectors - Inspect".

  STOP

• Not OK - The voltage is not 5.0 ± 0.2 VDC for both measurements.

  Repair: Replace the ECM. Refer to the diagnostic procedure Troubleshooting, "Replacing the ECM".

  STOP