C-9 Engine for TK711, TK721, TK722, TK732, TK741, TK751, and TK752 Track Feller Bunchers Engine Temperature Sensor Open or Short Circuit - Test Caterpillar

System Operation Description:

Use this procedure to troubleshoot the system only when there is an active diagnostic code or when a diagnostic code can easily be activated. This procedure covers open circuit diagnostic codes and short circuit diagnostic codes that are associated with the following sensors:

• Engine coolant temperature sensor

• Engine oil temperature sensor (middle)

• Engine oil temperature sensor (end)

• Intake manifold air temperature sensor

The troubleshooting procedures for the diagnostic codes of each temperature sensor are identical. The temperature sensors are sensors that have two terminals. The temperature sensors do not require supply voltage from the Electronic Control Module (ECM). The sensor common connection is shared between all of the temperature sensors. The common line is connected to each sensor connector terminal 2. The ECM monitors the voltage from terminal 1 (sensor output) of each sensor.

Illustration 1	g00995839
Schematic

Illustration 2	g01116862
P2 ECM connector (P2-18) Engine temperature sensor (common) (P2-32) Engine coolant temperature (P2-33) Engine oil temperature (end) (P2-34) Engine oil temperature (middle) (P2-35) Intake manifold air temperature

Test Step 1. Verify all Active Diagnostic Codes

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

2. Turn the keyswitch to the ON position. Wait at least 15 seconds for activation of the diagnostic codes.

3. Check Cat ET for any of the following diagnostic codes:
   • 110-03 Engine Coolant Temperature open/short to +batt

   • 110-04 Engine Coolant Temperature short to ground

   • 172-03 Intake Manifold Air Temp open/short to +batt

   • 172-04 Intake Manifold Air Temp short to ground

   • 175-03 Engine Oil Temperature open/short to +batt

   • 175-04 Engine Oil Temperature short to ground

   • 1715-03 Engine Oil Temperature Sensor #2 short to +batt

   • 1715-04 Engine Oil Temperature Sensor #2 short to ground

Expected Result:

One or more of the preceding diagnostic codes are active.

Results:

• OK - Proceed to Test Step 2.

• Not OK -

  Repair: If the preceding codes are logged but not active and the engine is not running properly, refer to Troubleshooting, "Troubleshooting without a Diagnostic Code". If the engine is running properly at this time, an intermittent condition may be causing the logged codes. Refer to Troubleshooting, "Electrical Connections - Inspect".

  STOP

Test Step 2. Inspect Electrical Connectors and Wiring

1. Thoroughly inspect ECM engine harness connector J2/P2 and the suspect sensor connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.

2. Perform a 45 N (10 lb) pull test on each of the wires in the sensor connector and the ECM connector that are associated with the active diagnostic code.

3. Verify that the latch tab of the connector is properly latched and that the latch tab of the connector has returned to the fully latching position.

4. Check the ECM connector (allen head screw) for the proper torque of 6 ± 1 N·m (55 ± 9 lb in).

5. Check the harness and wiring for abrasions and for pinch points from the sensor to the ECM.

Expected Result:

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

Results:

• OK - Proceed to Test Step 3.

• 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 3. Verify that the Diagnostic Code is Still Active

1. Turn the keyswitch to the ON position. Wait at least 15 seconds for activation of the diagnostic codes.

2. Access the "Active Diagnostic Code" screen on Cat ET. Check for active diagnostic codes.

3. Determine if the problem is related to an open circuit diagnostic code or a short circuit diagnostic code.

Expected Result:

An 03 diagnostic code or an 04 diagnostic code is active.

Results:

• 04 - An 04 diagnostic code is active at this time. Proceed to Test Step 5.

• 03 - An 03 diagnostic code is active at this time. Proceed to Test Step 4.

Test Step 4. Disconnect the Sensor in order to Create an Open Circuit

1. Turn the keyswitch to the OFF position.

2. Disconnect the sensor connector of the suspect sensor.

3. Turn the keyswitch to the ON position. Wait at least 15 seconds for activation of the diagnostic codes.

4. Access the "Active Diagnostic Code" screen on Cat ET. Check for an active 03 diagnostic code.

Expected Result:

An 03 diagnostic code for the disconnected sensor is now active.

Results:

• OK - A 04 diagnostic code was active before disconnecting the sensor. An 03 diagnostic code became active after disconnecting the sensor. Proceed to Test Step 6.

• Not OK - The 04 diagnostic code remains active. There is a short circuit between the sensor harness connector and the ECM. Leave the sensor disconnected. Proceed to Test Step 7.

Test Step 5. Create a Short Circuit Between the Signal and the Common Terminals at the Sensor Connector

1. Disconnect the suspect sensor.

2. Turn the keyswitch to the ON position.

3. Fabricate a jumper wire 150 mm (6 inches) long. Crimp a Deutsch terminal to both ends of the wire.

4. Monitor the "Active Diagnostic Code" screen before installing the jumper wire and after installing the jumper wire.

5. Install the jumper on the engine harness connector. Install one end of the jumper at the sensor signal (terminal 1). Install the other end of the jumper at the common connection for the engine temperature sensor (terminal 2). Wait at least 15 seconds for activation of the short circuit diagnostic code.

Expected Result:

A 04 diagnostic code is active when the jumper is installed. An 03 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 a new sensor.

  2. Check for active diagnostic codes. If the diagnostic code for the sensor does not return, install the new sensor.

  3. Verify that the repair eliminates the problem.

  4. Clear all logged diagnostic codes.

  STOP

• Not OK - The 03 diagnostic code remains active with the jumper in place. The most probable location for the open is in the sensor common or the sensor signal wire in the engine harness between the ECM and the sensor. Remove the jumper. Proceed to Test Step 7.

Test Step 6. Determine if the Short Circuit is in the Connector or in the Sensor

1. Thoroughly inspect the connector for moisture.

2. Inspect the seals and reconnect the sensor.

3. If the 04 diagnostic code reappears, the sensor is the problem.

   1. Temporarily connect a new sensor to the harness, but do not install the new sensor in the engine.

4. Check for a 04 diagnostic code while the new sensor is connected to the harness.

Expected Result:

The 04 diagnostic code is not present when a new sensor is connected.

Results:

• OK - Verify that the repair eliminates the problem. Clear the logged diagnostic codes.STOP

• Not OK -

  Repair: Repair the engine harness connector.

  STOP

Test Step 7. Check the Operation of the ECM by Creating Open and Short Circuits at the ECM Connector

1. Turn the keyswitch to the OFF position.

2. Disconnect the J2/P2 ECM connector. Thoroughly inspect both halves of the connector for signs of corrosion or moisture.

3. Turn the keyswitch to the ON position. Monitor the "Active Diagnostic Code" screen on Cat ET. Wait at least 15 seconds for activation of the code.

   An 03 diagnostic code should be active for the suspect sensor.

   Note: When the engine harness is disconnected, all of the 03 diagnostic codes for the pressure sensors will be active. This is normal. Disregard the diagnostic codes for the pressure sensors.

4. Turn the keyswitch to the OFF position.

5. Fabricate a jumper wire 150 mm (6 inches) long. Crimp a Deutsch socket to both ends of the wire.

6. Install the jumper wire on the ECM pin terminal. Insert the jumper wire between the terminal for the suspect sensor signal and the common connection for the engine temperature sensor (terminal 18).

   A 04 diagnostic code should be active when the jumper wire is installed.

Expected Result:

03 diagnostic codes are active when the jumper is removed. 04 diagnostic codes are active when the jumper is installed.

Results:

• OK - The ECM is working properly. There is a problem in the harness.

  Repair: Repair the harness or replace the harness. Verify that the repair eliminates the problem.

  STOP

• Not OK - One of the following conditions exists: The 03 diagnostic code is not active when the harness is disconnected. The 04 diagnostic code is not active when the jumper wire is installed.

  Repair: Perform the following repair:

  1. Temporarily connect a test ECM.

  2. Remove all jumpers and replace all connectors.

  3. Recheck the system for active diagnostic codes.

  4. Repeat the test step.

  5. If the problem is resolved with the test ECM, reconnect the suspect ECM.

  6. If the problem returns with the suspect ECM, replace the ECM. Refer to Troubleshooting, "Replacing the ECM".

  7. Verify that the repair eliminates the problem.

  STOP