SEAL KIT 8C5777 - Caterpillar

Illustration 4 g00761537
Diode leads
Select the "Diode Check" function on a digital voltmeter.
Refer to Illustration 4. Place the red lead of the digital voltmeter on the diode at location (A). Place the black lead of the digital voltmeter on the diode at location (B).
Measure the voltage drop across the diode. Expected Result:The voltage drop across the diode is less than one volt.Results:
OK - The voltage drop across the diode is less than one volt. The voltage drop across the diode is OK. Proceed to Test Step 13.
Not OK - The voltage drop across the diode is greater than one volt.Repair: The diode is damaged. Replace the diode. Verify that the problem is resolved.STOPTest Step 13. Test the Diode for Current Flow
Reverse the position of the leads for the digital voltmeter.
Measure the voltage drop across the diode. Expected Result:For a diode that is operating properly, the digital voltmeter will indicate an OL across the diode.Results:
OK - The digital voltmeter indicates an OL across the diode for this measurement. The diode is OK. Proceed to Test Step 14.
Not OK - The digital voltmeter does not indicate an OL across the diode.Repair: The diode is damaged. Replace the diode. Verify that the problem is resolved.STOPTest Step 14. Check for Power at the Exhaust Brake Solenoid
Connect a test lamp between terminal 1 of the exhaust brake solenoid and engine ground.
Connect Cat ET to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
Restore electrical power to the engine ECM.
Proceed to the "Diagnostic Overrides" screen on Cat ET.
Activate the override for the exhaust brake. The system will activate for ten seconds.
Monitor the test lamp during the override. Expected Result:The test lamp illuminates for ten seconds.Results:
OK - The test lamp illuminates.Repair: The voltage is present at the exhaust brake solenoid. Check for continuity of the ground circuit for the exhaust brake solenoid before proceeding. If the ground circuit is OK, replace the exhaust brake solenoid. Verify that the problem is resolved.STOP
Not OK - The test lamp does not illuminate.Repair: There is a problem with the wire between the exhaust brake relay and the exhaust brake solenoid. Repair the wire and/or terminal connections.STOPTest Step 15. Test the Diode for the Relay Coil for the Cause of the Code
Remove the diode between terminal 1 and terminal 2 of the coil for the exhaust brake relay.
Restore electrical power to the engine ECM.
Proceed to the "Diagnostic Overrides" screen on Cat ET.
Activate the override for the exhaust brake. The system will activate for ten seconds.
Monitor the active diagnostic code screen on Cat ET. Look for an active -5 code. Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
Remove electrical power from the engine ECM. Expected Result:The 6 code is no longer active during the test.Results:
OK - A -6 code was active before the diode was disconnected. No code is active after the diode is disconnected.Repair: The circuit for the exhaust brake relay is OK. Connect a new diode to the coil of the exhaust brake