0343483 JOHNSON ENGINE COVER, Lower, port

Table 1
Diagnostic Codes Table    
Code    Conditions which Generate this Code    System Response    
286-5 EMS Oil Lamp open/short to ground     The Electronic Control Module (ECM) detects a short to ground or an open condition exists.
The engine's ECM has been powered for two seconds.     The code is logged.    
286-6 EMS Oil Lamp short to +batt     The ECM detects a short to a voltage source.
The engine's ECM has been powered for two seconds.    The EMS oil pressure lamp is used to indicate that a low oil pressure condition exists or that a diagnostic code is active for the oil pressure sensor. The EMS oil pressure lamp is illuminated by the "Engine/Pump Control". The ECM sends a signal in order to illuminate the EMS oil pressure lamp to the "Engine/Pump Control" from terminal P1-21. When terminal P1-21 is grounded, the output to the "Engine/Pump Control" is off and the "Engine/Pump Control" will not illuminate the EMS oil pressure lamp. When terminal P1-21 is open, the output to the "Engine/Pump Control" is on and the "Engine/Pump Control" will illuminate the EMS oil pressure lamp.
Illustration 1 g01454778
Typical schematic of circuit
Illustration 2 g01454779
P1 ECM connector (P1-5) −Battery (P1-6) +Battery (P1-21) Engine oil pressure
Illustration 3 g01454932
P2 ECM connector (P2-1) Speed timing power (P2-36) Analog sensor powerTest Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF position.
Turn the circuit breaker for the battery to the OFF position.
Illustration 4 g01139425
ECM (1) J1/P1 connectors (2) J2/P2 connectors
Thoroughly inspect the ECM connector J1/P1. Inspect all of the other connectors for the circuit. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the ECM connector (allen head screw) for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and the wiring for abrasion and for pinch points.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 - The harness and the 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.STOPTest Step 2. Test the Circuit for the EMS Oil Pressure Lamp
Turn the circuit breaker for the battery to the ON position.
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the keyswitch to the ON position. Do not start the engine.
Use the diagnostic test on Cat ET in order to activate the override for the "Low Oil Pressure Lamp". Activate the override by setting the status of the signal to OFF.
Monitor the EMS oil pressure lamp. The lamp should be illuminated.
Use the diagnostic test on Cat ET to deactivate the override for the "Low Oil Pressure Lamp" by setting the signal status to GROUND.
Monitor the EMS oil pressure lamp. The lamp should not be illuminated.Expected Result:The circuit is operating correctly.Results:
OK - The circuit is operating correctly.Repair: The problem may be intermittent. If the problem is intermittent, check for a problem in a connector. Refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - The circuit did not operate correctly. Proceed to Test Step 3.Test Step 3. Check for a Short to Ground or for a Short to Power in the Harness
Turn the keyswitch to the OFF position.
Disconnect ECM connectors P1 and P2.
Measure the resistance between P1-21 and the following terminals:
P1-5 −Battery
P1-6 +Battery
P2-1 Speed timing power
P2-36 Analog sensor powerExpected Result:The resistance measurements indicate an open circuit.Results:
OK - The resistance measurements indicate an open circuit. Proceed to Test Step 4.
Not OK - There is a short between two or more wires in the harness.Repair: Repair the harness or replace the harness.STOPTest Step 4. Check for an Open in the Harness
Disconnect the wire F400-GY from the "Engine/Pump Control".
Create a short between wire F400-GY and engine ground.
Measure the resistance between terminals P1-21 and P1-5 on ECM connector P1.
Return all wires and connectors to the original configuration.Expected Result:The resistance measurement indicates a short circuit.Results:
OK - The resistance measurement indicates a short circuit. Wire F400-GY does not have an open. Proceed to Test Step 5.
Not OK - The resistance measurement indicates an open circuit.Repair: Repair wire F400-GY.STOPTest Step 5. Check the Signal Voltage at the ECM
Turn the keyswitch to the ON position. Do not start the engine.
Use signal reading probes to measure the voltage between terminal P1-21 and engine ground.
Use the diagnostic test on Cat ET in order to activate the override for the "Low Oil Pressure Lamp". Activate the override by setting the status of the signal to OFF.
Measure the voltage.Expected Result:The voltage is 1.3 0.5 VDC.Results:
OK - The voltage is correct.Repair: Verify that the problem is resolved.STOP
Not OK - The voltage is incorrect.Repair: There is a problem with the ECM. Perform the following procedure:
Temporarily connect a test ECM. Refer to Troubleshooting, "ECM - Replace".
Recheck the circuit in order to ensure that the original problem has been resolved.If the problem is resolved with the test ECM, install the suspect ECM. If the problem returns with the suspect ECM, replace the ECM. Verify that the problem is resolved.If the problem is not resolved with the test ECM, install the original ECM. There is a problem in the wiring. Recheck the system.STOP