C6.6 Generator Set Caterpillar

Use this procedure if another test procedure has directed you here. Also use this procedure when there is an active fault for the glow plug start aid relay current.

Use this procedure for the following diagnostic codes:

• 2246-6 Glow Plug Start Aid Relay Current High

The following background information is related to this procedure:

The starting aid is used to improve the engine starting when the engine is cold. With the keyswitch in the ON position, the engine Electronic Control Module (ECM) will monitor the coolant temperature and the engine intake manifold air temperature in order to decide if the glow plugs are required to be switched ON. If the glow plugs are required, then the ECM will activate the starting aid relay for a controlled period of time. While the glow plug start aid relay is activated, the glow plug start aid relay will supply power to the glow plugs.

Electronic Service Tool Test Aid

The electronic service tool includes the test "Glow Plug Override Test". The "Glow Plug Override Test" will assist the analysis of the cold starting aid.

Overview of the Glow Plug Override Test

This glow plug override test switches on the cold starting aid when the engine is not running. The glow plug override test aids the analysis of the circuit for the glow plug start aid relay.

Illustration 1	g02053797
Typical schematic for the starting aid system

Illustration 2	g02053833
Typical view of the pin locations on the P1 connector for the starting aid (1) Ground (GND) (2) Ground (GND) (3) Ground (GND) (9) Ground (GND) (10) Ground (GND) (57) Start aid control

Test Step 1. Inspect Electrical Connectors and Wiring

1. Inspect the following connectors:
   • P1 connector

   • P2 connector

2. Inspect the terminal connections on the glow plug start aid relay. 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 that are associated with the glow plug starting aid.

4. Check the screw for the ECM connector for the correct torque of 5.0 N·m (44 lb in).

5. Check the harness for abrasion and pinch points from the glow plugs back to the ECM.

6. Check that the fuses are not blown.

Expected Result:

All connectors, pins and sockets are correctly coupled and/or inserted. The harness is free of corrosion, abrasion and pinch points. The fuses are not blown.

Results:

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

• Not OK - There is a fault with the harness and connectors.

  Repair: Repair the connectors or the harness and/or replace the connectors or the harness. Ensure that all of the seals are correctly in place and ensure that the connectors are completely coupled. Replace blown fuses.Verify that the repair has eliminated the fault.

  STOP

Test Step 2. Check for Active Diagnostic Codes

1. Connect the electronic service tool to the diagnostic connector.

2. Turn the keyswitch to the ON position.

   Note: Do not start the engine.

3. Use the electronic service tool to select the "Glow Plug Override Test" in order to turn on the power for the glow plugs.

4. Check for active diagnostic codes or recently logged diagnostic codes.

Expected Result:

The following diagnostic code is active or recently logged:

• 2246-6 Glow Plug Start Aid Relay Current High

Results:

• OK - The expected diagnostic code is active or recently logged. Proceed to Test step 3.

• Not OK - An active diagnostic code or a recently logged diagnostic code was not displayed.

  Repair: Perform one of the following procedures:

  • If an intermittent fault is suspected, use the electronic service tool to perform a "Wiggle Test" in order to locate intermittent connections.

  • If there is a fault on the glow plug or a fault on the starting aid and a diagnostic code is not displayed, then there may be a fault with the glow plug switched power circuit or there may be an open circuit in the relay coil circuit. The ECM does not monitor the status of these tests. Refer to Systems Operation, Testing and Adjusting, "Glow Plugs - Test".

  STOP

Test Step 3. Check the Wiring for a Short Circuit

1. Turn the keyswitch to the OFF position.

2. Disconnect the P1 connector from the ECM.

3. Check the connector, pins and the sockets for corrosion or damage.

4. Check the resistance between P1:57 and each of the pins on the P1 connector.

Expected Result:

The resistance between P1:57 and each of the pins on the P1 connector is more than 10,000 Ohms.

Results:

• OK - The harness connects the ECM to the glow plug start aid relay and there are no shorts to other circuits. The ECM or the glow plug start aid relay is suspect. Proceed to Test Step 4.

• Not OK - The harness is faulty.

  Repair: If the resistance between P1:57 and each of the other pins on the J1 connector is less than 10,000 Ohms then there is a short circuit or high resistance in the connection to another wire. Locate the short circuit in the harness. Repair the connectors or the harness and/or replace the connectors or the harness. Ensure that all of the seals are correctly in place and ensure that the connectors are correctly coupled. Replace any fuses that may be open circuit.Verify that the repair has eliminated the fault.

  If the fault still exists, proceed to Test Step 4.

Test Step 4. Bypass the ECM In Order to Check the Operation of the Glow Plug Start Aid Relay

1. Turn the keyswitch to the OFF position.

2. Disconnect the connection from test point "D" on the glow plug start aid relay.

3. Connect a jumper wire between the battery ground and terminal "D" on the glow plug start aid relay.

4. Measure the voltage from the battery ground and terminal "B" on the glow plug start aid relay.

5. Turn the keyswitch to the ON position.

   Note: The engine has not been started at this Test Step.

6. Measure the voltage from the battery ground and terminal "B" on the glow plug start aid relay.

Expected Result:

The keyswitch is in the OFF position. The voltage should be 0 Volts DC.

The keyswitch is in the ON position. The measured voltage for the 12 Volt systems is a constant 10.5 to 13.5 Volts DC. The measured voltage for the 24 Volt systems is a constant 21.0 to 27.0 Volts DC.

Results:

• OK - The glow plug start aid relay is operating correctly. Reconnect the connection to test point "D" on the glow plug start aid relay. Proceed to Test Step 5.

• Not OK - The glow plug start aid relay is faulty.

  Repair: Replace the glow plug start aid relay. Verify that the repair eliminates the fault.

  If the fault still exists, proceed to Test step 5.

Test Step 5. Check the ECM

1. Make sure that the latest flash file for the application is installed in the ECM. Refer to Troubleshooting, "Flash Programming".

2. Contact the Technical Communicator.

   Note: This consultation can greatly reduce the repair time.

3. If the Technical Communicator recommends the use of a test ECM, install a test ECM. Refer to Troubleshooting, "Replacing the ECM".

4. Use the electronic service tool in order to perform a "Glow Plug Override Test".

Expected Result:

The test ECM functions correctly. Performing the "Glow Plug Override Test" energizes the glow plugs.

Results:

• OK - The test ECM operates correctly.

  Repair: The fault is resolved with the test ECM.

  1. Reconnect the suspect ECM.

  2. Use the electronic service tool in order to perform a "Glow Plug Override Test".

  3. If the fault returns with the suspect ECM, replace the ECM.

  4. Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair eliminates the fault.

  STOP

• Not OK - Repeat the test procedure from Test Step 1.