C13 and C15 Engines for Combat and Tactical Vehicles Caterpillar

Note: Valid only if engine is equipped with an engine coolant diverter.

Use this procedure to troubleshoot any suspect problems with the solenoid circuit for the coolant diverter valve.

This procedure covers the following diagnostic codes:

• 284-05 Engine Coolant Diverter current low

• 284-06 Engine Coolant Diverter current high

During normal operation, coolant is sent to the air intake system in order to cool the intake air. A jacket water aftercooler in the air lines after the turbochargers cools the air before the air enters the air-to-air aftercooler. When the vehicle is at idle in cold climates, the aftercooler may overcool the engine. The coolant diverter valve stops the flow of coolant to the aftercooler in order to prevent the coolant temperature from becoming too low. Diverting the coolant will also prevent the temperature in the cab from becoming too low.

"Coolant Diverter Valve Test"

The "Coolant Diverter Valve Test" is a diagnostic test that is available on the Caterpillar Electronic Technician (ET). The test helps diagnose problems with the solenoid for the coolant diverter valve. A small current is applied to the circuit at all times. This allows the Engine Control Module (ECM) to detect open circuits when the valve is not actuated. A short circuit will only be detected when the valve is actuated.

The following conditions must be met before the "Coolant Diverter Valve Test" will function:

• Engine speed is 0.

• Vehicle speed is 0.

• The neutral switch is in the Neutral position.

Illustration 1	g01098796
Schematic

Illustration 2	g01098798
P2 ECM connector (5) Solenoid for the coolant diverter valve (79) Return for the intake valve actuator

Test Step 1. Inspect Electrical Connectors and Wiring

1. Turn the key switch to the OFF position.

2. Thoroughly inspect the J2/P2 ECM connector and the solenoid connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.

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

4. Check the ECM connector (allen head screw) for the proper torque of 6 N·m (55.0 lb in).

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

Expected Result:

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

Results:

• OK - The harness and wiring are OK. Proceed to Test Step 2.

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

  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 the Cat ET to the service tool connector.

2. Turn the key switch to the ON position.

3. Check for active diagnostic codes that are related to the coolant diverter valve.

4. Monitor the active diagnostic code screen on the electronic service tool. Check and record any active diagnostic codes.

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

5. Determine if the problem is related to the low current diagnostic code 05 or the high current diagnostic code 06.

Expected Result:

No diagnostic codes are active.

Results:

• OK - No diagnostic codes are active.

  Repair: The problem may have been related to a faulty connection in the harness. Carefully reinspect the connectors and wiring. Refer to Troubleshooting, "Electrical Connectors - Inspect".

  STOP

• Not OK - A low current diagnostic code (05) is active at this time. Proceed to Test Step 3.

• Not OK - An high current diagnostic code (06) is active at this time. Proceed to Test Step 5.

Test Step 3. Short the Wires at the Solenoid

1. Turn the key switch to the OFF position.

2. Disconnect the connector for the coolant diverter valve.

3. Fabricate a jumper wire to short terminal 1 and terminal 2 of the connector for the solenoid on the engine harness.

4. Turn the key switch to the ON position.

5. Access the "Special Tests" under the "Diagnostics" menu.

6. Start the "Coolant Diverter Valve Test" on Cat ET.

7. Once Cat ET displays the status of the coolant diverter valve, stop the "Coolant Diverter Valve Test".

Expected Result:

The test indicated "Not Active: Device Short" with the jumper wire in place.

Results:

• OK - The test indicated "Not Active: Device Short". The ECM recognized the short at the connector for the coolant diverter valve. The harness wiring is OK.

  Repair: Temporarily connect a new coolant diverter valve to the harness, but do not install the new coolant diverter valve on the engine. Verify that there are no active diagnostic codes for the coolant diverter valve. If there are no active diagnostic codes for the coolant diverter valve, permanently install the new coolant diverter valve. Clear any logged diagnostic codes.

  STOP

• Not OK - The test indicated "Not Active: Device Open". The ECM did not see the short at the connector for the coolant diverter valve. Proceed to Test Step 4.

Test Step 4. Short the Circuit at the ECM

1. Turn the key switch to the OFF position.

2. Disconnect the P2 ECM connector.

3. Remove the wires from P2-5 (coolant diverter valve) and P2-79 (return for the intake valve actuator).

4. Fabricate a jumper wire to short P2-5 (coolant diverter valve) and P2-79 (return for the intake valve actuator).

5. Reconnect the P2 ECM connector.

6. Turn the key switch to the ON position.

7. Access the "Special Tests" under the "Diagnostics" menu.

8. Start the "Coolant Diverter Valve Test" on Cat ET.

9. Once Cat ET displays the status of the coolant diverter valve, stop the "Coolant Diverter Valve Test".

Expected Result:

The test indicated "Not Active: Device Short" with the jumper wire in place.

Results:

• OK - The test indicated "Not Active: Device Short" with the jumper wire in place. The ECM recognized the short.

  Repair: Check continuity of the wire T855-BU(Blue) between the connector for the coolant diverter valve and P2-5. If the wire is open, replace the wire.

  Check continuity of wire H807-YL(Yellow) between the connector for the coolant diverter valve and P2-79. If the wire is open, replace the wire.

  STOP

• Not OK - The test indicated "Not Active: Device Open" with the jumper wire in place. The ECM did not recognize the short circuit.

  Repair: Replace the ECM. Refer to Troubleshooting, "Replacing the ECM". Verify that the problem is resolved.

  Verify that the repair eliminates the problem.

  STOP

Test Step 5. Create an Open at the Solenoid

1. Turn the key switch to the OFF position.

2. Disconnect the connector for the coolant diverter valve.

3. Turn the key switch to the ON position.

4. Access the "Special Tests" under the "Diagnostics" menu.

5. Start the "Coolant Diverter Valve Test" on Cat ET.

6. Once Cat ET displays the status of the coolant diverter valve, stop the "Coolant Diverter Valve Test".

Expected Result:

The test indicates "Not Active: Device Open".

Results:

• OK - The test indicates "Not Active: Device Open". The ECM recognized the open at the connector for the coolant diverter valve. The harness wiring is OK.

  Repair: Temporarily connect a new coolant diverter valve to the harness, but do not install the new coolant diverter valve on the engine. Verify that there are no active diagnostic codes for the coolant diverter valve. If there are no active diagnostic codes for the coolant diverter valve, permanently install the new coolant diverter valve. Clear any logged diagnostic codes.

  STOP

• Not OK - The test indicates "Not Active: Device Short". Proceed to Test Step 6.

Test Step 6. Create an Open at the ECM

1. Turn the key switch to the OFF position.

2. Disconnect the P2 ECM connector.

3. Check the ECM connector for corrosion and for moisture.

4. Remove the wires from P2-5 (coolant diverter valve valve) and P2-79 (Return for the intake valve actuator).

5. Reconnect the P2 ECM connector.

6. Turn the key switch to the ON position.

7. Access the "Special Tests" under the "Diagnostics" menu.

8. Start the "Coolant Diverter Valve Test" on Cat ET.

9. Once Cat ET displays the status of the coolant diverter valve, stop the "Coolant Diverter Valve Test".

Expected Result:

The test indicates "Not Active: Device Open".

Results:

• OK - The test indicates "Not Active: Device Open". The ECM recognized the open at the ECM.

  Repair: Measure the resistance between wire T855-BU(Blue) and every terminal on ECM connector P1 and ECM connector P2. Measure the resistance between wire T855-BU(Blue) and engine ground. If the wire is shorted, replace the wire.

  Measure the resistance between wire H807-YL(Yellow) and every terminal on ECM connector P1 and ECM connector P2. If the wire is shorted, replace the wire.

  STOP

• Not OK - The test indicates "Not Active: Device Short". The ECM did not recognize the open.

  Repair: Replace the ECM. Refer to Troubleshooting, "Replacing the ECM". Verify that the problem is resolved.

  STOP