0123496 JOHNSON DRIVE GEAR, Starboard

Table 1
Diagnostic Trouble Codes For The Glow Plug Starting Aid
J1939 Code CDL Code Code Description
(code descriptions may vary) Comments
676-6 2246-6 Engine Glow Plug Relay : Current Above Normal The Electronic Control Module (ECM) detects the following conditions:
The engine is not cranking.
The ECM has been powered for at least one second.
There is a high current condition (short circuit) in the glow plug start aid relay circuit for more than 2 seconds.
The warning light will come on. The diagnostic code will be logged. An ECM that was previously blank will require a total of 2 hours of operation before the diagnostic code will be logged.
The ECM is unable to activate the relay for the glow plug starting aid. The glow plugs will not operate or the glow plugs will operate all the time. The engine may be difficult to start in cold temperatures and the exhaust may emit white smoke.
Follow the troubleshooting procedure to identify the root cause of the fault. 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 ECM monitors the following parameters to decide if the glow plugs need to be switched ON:
Coolant temperature
Intake manifold air temperatureIf the glow plugs are required, then the ECM will activate the starting aid relay for a controlled period. While the glow plug start aid relay is activated, the glow plug start aid relay will supply power to the glow plugs. If a "Wait To Start" lamp is installed, then this lamp will be illuminated to indicate the "Wait To Start" period."Wait to Start Lamp"This feature may be included as an option.When glow plugs need to be activated prior to starting, a lamp will indicate that the operator needs to "Wait to Start". Starting aids may be used during the cranking of the engine. Starting aids may be used if the engine has previously been started. The "Wait to Start" lamp will not be active in these conditions.Electronic Service Tool Test AidThe electronic service tool includes the test "Glow Plug Start Aid Override Test". This test will assist the analysis of the cold starting aid.Overview of the Glow Plug Start Aid Override TestThis glow plug start aid override test switches on the cold starting aid when the engine is not running. The glow plug start aid override test aids the analysis of the circuit for the glow plug start aid relay.
Illustration 1 g06113735
Schematic for the glow plug starting aid circuit
Not all connectors are shown. Refer to the appropriate Electrical Schematic.
Table 2
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Check that the fuses are not blown.
B. Inspect the terminals on the glow plug start aid relay and then inspect the connector on the flying lead from the relay. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
C. Inspect the bus bar for the glow plugs. Ensure that the nuts that secure the bus bar to each glow plug are tightened to a torque of 2 N m (17 lb in). Ensure that the bus bar is not shorted to the engine.
D. Perform a 45 N (10 lb) pull test on each of the glow plug starting aid wires in the ECM connector.
E. Check the screw for the ECM connector for the correct torque of 6 N m (53 lb in).
F. Check the harness for abrasion and pinch points from the glow plugs back to the ECM.
Loose connection or damaged wire
Result: There is a fault in a connector or the wiring.
Repair: Repair any faulty connectors or replace the wiring harness. Ensure that all the seals are properly in place and ensure that the connectors are correctly coupled.
Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
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. The bus bar is secured to the glow plugs and not shorted to ground.
Proceed to Test Step 2.
2. Check for Active Diagnostic Codes
A. Connect the electronic service tool to the diagnostic connector.
B. Turn the keyswitch to the ON position.
Note: Do not start the engine.
C. Use the electronic service tool to select the "Glow Plug Start Aid Override Test" to turn on the power for the glow plugs.
D. Check for active diagnostic codes or recently logged diagnostic codes that are listed in Table 1.
Diagnostic codes
Result: No diagnostic codes are present.
There may be an intermittent fault in an electrical component between the ECM and the glow plugs. The problem may be inside an electrical connector. Refer to Troubleshooting, "Electrical Connector - Inspect" to identify intermittent faults.
There may be a fault in the glow plug switched power circuit. The ECM does not monitor the status of this condition.
Proceed to Test Step 5 to test this circuit.
Result: Diagnostic code 676-6 (2246-6) is active or recently logged.
Proceed to Test Step 3.
3. Create an Open Circuit at the Relay
A. Turn the keyswitch to the OFF position.
B. Disconnect the glow plug start aid relay.
C. Use the electronic service tool to select the "Glow Plug Start Aid Override Test" to turn on the power for the glow plugs.
D. Use the electronic service tool to check for active diagnostic codes. Wait at least 30 seconds for activation of the diagnostic codes.
Diagnostic codes
Result:A 676-5 (2246-5) diagnostic code is active with the relay disconnected.
Repair: Install a replacement glow plug start aid relay.
Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
Result: The 676-6 (2246-6) diagnostic code is still active with the relay disconnected.
Proceed to Test Step 4.
4. Check the Wiring Between the Relay and the ECM for a Short Circuit
A. Disconnect the P1 connector.
B. Inspect the P1 connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
C. Use a suitable multimeter to measure the resistance between P1:20 and all other terminals on the P1 connector.
Greater than 1 k Ohm
Result: At least one