0437194 JOHNSON ENGINE COVER ASSY., 70

Illustration 1 g00910938
Test Step 1. Check for Connector Damage
Turn the circuit breaker for the engine to the OFF position.
Turn the keyswitch to the OFF position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" 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 of 6.0 N m (55 lb in).
Check the customer connector (allen head screw) for the proper torque of 2.25 0.25 N m (20 2 lb in).
Check the harness and the wiring for abrasion and pinch points.Expected Result:The connectors and wiring should be free of the following problems: damage, corrosion, abrasion and incorrect attachment.Results:
OK - The connectors and wiring are okay. Proceed to test step 2.
Not OK - The connectors and/or wiring need repair.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Stop.Test Step 2. Check the Voltage at the Battery Post.
Turn the circuit breaker for the engine to the ON position.
Turn the keyswitch to the ON position. The engine should be off.
Measure the voltage at the battery posts.Expected Result:The voltage should be 24 3 VDC.Results:
OK - The voltage is 24 3 VDC. Proceed to test step 3.
Not OK - The voltage is not 24 3 VDC.Repair: There is a problem with the batteries or the charging system. Refer to Testing and Adjusting, "Charging System". Stop.Test Step 3. Check the Voltage to the ECM.
Turn the keyswitch to the OFF position. The engine should be off.
Turn the circuit breaker for the engine to the OFF position.
Remove ECM connector J1/P1.
Turn the circuit breaker for the engine to the ON position.
Turn the keyswitch to the ON position. The engine should be off.
Measure the voltage between P1-4 and P1-11 at the ECM connector P1.
Measure the voltage between P1-6 and P1-5 at the ECM connector P1.Expected Result:The voltage should be 1 VDC from the voltage at the battery terminals.Results:
OK - The voltage should be 1 VDC from the voltage at the battery terminals. The voltage at the ECM is okay. Proceed to test step 4.
Not OK - The voltage should be 1 VDC from the voltage at the battery terminals. The voltage is not correct at the ECM.Repair: There is an open circuit or excessive resistance in the wiring or connections between the batteries and the ECM. Verify that the breaker for the Engine is not tripped. Verify that the Main breaker is not tripped. Verify that the connection for the engine ground is clean and tight. Repair the connectors or wiring and/or replace the connectors or wiring. Stop.Test Step 4. Check the Voltage at the Input for the Keyswitch at the ECM.
Measure the voltage between wire 113-OR from ECM connector P1-23 and wire 229-BK from ECM connector P1-11.
Turn the keyswitch to the OFF position. The engine should be off.
Turn the circuit breaker for the engine to the OFF position.
Reconnect all wires and connectors.Expected Result:The voltage should be 24 3 VDC.Results:
OK - The voltage is 24 3 VDC. Proceed to test step 7.
Not OK - The voltage is not 24 3 VDC. Proceed to test step 5.Test Step 5. Check the Voltage at the Keyswitch.
Turn the circuit breaker for the engine to the ON position.
Turn the keyswitch to the ON position. The engine should be off.
Measure the voltage between terminal R and engine ground at the keyswitch.
Turn the keyswitch to the OFF position. The engine should be off.Expected Result:The voltage should measure 24 3 VDC.Results:
OK - The voltage measures 24 3 VDC. Proceed to test step 6.
Not OK - The voltage does not measure 24 3 VDC.Repair: Check for 24 3 VDC at terminal B of the keyswitch. If voltage is present on terminal B of the keyswitch, replace the keyswitch. If voltage is not present on terminal B of the keyswitch, verify that the breaker for the keyswitch is not tripped. Verify that the Main breaker (if applicable) is not tripped. Repair the wiring and/or terminals between the keyswitch and the Battery. Stop.Test Step 6. Check the Voltage at the Main Power Relay.
Turn the keyswitch to the ON position. The engine should be off.
Measure the voltage between the fuse for the Monitor and engine ground.
Turn the keyswitch to the OFF position. The engine should be off.Expected Result:The voltage should measure 24 3 VDC.Results:
OK - The voltage measures 24 3 VDC.Repair: Verify that the fuse for the Monitor is not tripped. Repair the wiring and/or connectors between the fuse for the Monitor and the input for the keyswitch at the ECM. Stop.
Not OK - The voltage does not measure 24 3 VDC.Repair: Verify that 24 3 VDC is present at the Main power relay on wire 177-RD and on wire 308-YL. If voltage is not present on wire 308-YL, replace the wire 308-YL. If voltage is not present on wire 177-RD, verify that the Main breaker (if applicable) is not tripped. Check the wire 200-BR for continuity to ground from the Main power relay. If the wire to ground is okay and 24 3 VDC is present on the wires 177-RD and 308-YL at the Main power relay, replace the Main power relay. Stop.Test Step 7. Check for "ACTIVE" Diagnostic Codes.
Turn the circuit breaker for the engine to the ON position.
Turn the keyswitch to the ON position. The engine should be off.
Connect the Caterpillar Electronic Technician (ET) to the cab service tool connector J42. Start the Cat ET.
Check for active diagnostic