0303844 JOHNSON PLATE,Co-pilot

Illustration 1 g01331456
Schematic for the CAN data link (31-Pin MIC)
Illustration 2 g01331458
Schematic for the CAN data link (70-Pin MIC)
Test Step 1. Inspect The Electrical Connectors and the Wiring for the CAN A Bus
Illustration 3 g01625111
ECM pin locations
(48) CAN A Data Link +
(58) CAN A Data Link -
(68) Battery -
Illustration 4 g01331454
Pin locations on the fuel pump connector P40.
(1) CAN A Data Link -
(2) CAN A Data Link +
(6) Pump supply -
(7) Pump supply +
Turn the keyswitch to the OFF position.
Check the connectors and wiring for the following faults: damage, corrosion, abrasion, and incorrect attachment.
Pay close attention to the following areas:
ECM connector J1/P1
P1:48 CAN A Data Link +
P1:58 CAN A Data Link -
P40:2 CAN A Data Link +
P40:1 CAN A Data Link -Refer to Troubleshooting, "Electrical Connectors - Inspect" for more information.Expected Result:The connectors and wiring should be free of the following faults: damage, corrosion, abrasion, and incorrect attachment.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Repair the CAN A data link circuit. Replace the cables or the connectors that are causing the fault. Ensure that all seals are properly placed and that all connectors are secured correctly.Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.STOPTest Step 2. Check the CAN A Data Link Between the ECM and P40 Fuel Injection Pump Control Unit Connector for an Open Circuit
Disconnect P1 from the ECM.Note: Do not disconnect P40 Fuel Injection Pump Connector.
Measure the resistance between terminal P1:48 and terminal P1:58.Expected Result:The readings should be between 110 ohms and 130 ohms.Results:
OK - Proceed to Test Step 3.
Not OK - Repair: There is an open circuit in the harness between the P1 ECM connector and the control unit for the fuel injection pump. Repair the harness or replace the harness.STOPTest Step 3. Check the CAN A Data Link Between the ECM and P40 Fuel Injection Pump Control Unit Connector for a Short Circuit
Disconnect P1 from the ECM.
Disconnect P40 Fuel injection Pump Connector.
Measure the resistance between terminal P1:58 and a suitable engine ground.
Measure the resistance between terminal P1:48 and a suitable engine ground.Expected Result:The readings should indicate an open circuit.Results:
OK - Proceed to Test Step 4.
Not OK - Repair: There is a short circuit in the harness between the P1 ECM connector and the control unit for the fuel injection pump. Repair the harness or replace the harness.Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.STOPTest Step 4. Verify the Supply Voltage at the Fuel Injection Pump
Turn the keyswitch to the OFF position.
Disconnect the P40 connector from the fuel injection pump.
Turn the keyswitch to the ON position.
Measure the voltage between terminal J40:7 and terminal J40:6.
Turn the keyswitch to the OFF position.
Reconnect the P40 connector.Expected Result:The voltage for a 12 Volt system should be constant. The voltage should be between 11.0 Volts DC and 13.5 Volts DC.The voltage for a 24 Volt system should be constant. The voltage should be between 22.0 Volts DC and 27.0 Volts DC.Results:
OK - Repair: Perform the following repairs:
Temporarily connect a test ECM.Note: The test ECM should be programmed with the correct software. All parameters should be set to the same value as the suspect ECM.
If the fault is eliminated with the test ECM, reconnect the suspect ECM.
If the fault returns with the suspect ECM, then the suspect ECM is faulty. Replace the suspect ECM.STOP
Not OK - No voltage or the voltage is less than the permissible limit.Repair: Refer to Troubleshooting, "Fuel Injection Pump Circuit - Test".Verify that the repair has eliminated the fault.STOPTest Step 5. Inspect the Electrical Connectors and the Wiring for the CAN B (J1939) Bus
Illustration 5 g01625112
ECM pin locations
(52) CAN B (J1939) Data Link +
(61) CAN B (J1939) Data Link -
Illustration 6