CONE-BEARING 7L6551 - Caterpillar

System Operation Description:This procedure is used in order to test the Cat data link ("CDL") circuit.Test Step 1. INSPECT ELECTRICAL CONNECTORS AND WIRING.
Turn the keyswitch to the OFF position.
Check the connectors and wiring for the following conditions: damage, corrosion, abrasion, pinch points and incorrect attachment. Expected Result:The connectors and wiring are correct.Results:
OK - The connectors and wiring are correct. Go to Test Step 2.
NOT OK - The connectors and wiring are not correct.Repair: Repair the part or replace the part.STOPTest Step 2. MEASURE THE RESISTANCE THROUGH THE "MJB-ECM" J3 HARNESS.
Table 1
Engine CDL+ CDL-
3126B 8 9
3406E 9 3
3196 9 3
3412E 9 3
C-12
C15
C18 8 9
C30
C32 9 3
Disconnect the ECM from the engine harness.
Disconnect the "MJB-ECM" J3 connector from the marine junction box.
Install a jumper between the ECM CDL+ and CDL- wires. Refer to table 1.
Measure the resistance between the CDL+ (pin 7) and the CDL- (pin 6) contacts on the connector for the marine junction box. Wiggle the harness during the measurement in order to reveal an intermittent condition. Expected Result:The resistance is less than 10 Ohms.Results:
OK - The resistance is less than 10 Ohms. Go to Test Step 3.
NOT OK - The resistance is NOT less than 10 Ohms. There is an open circuit.Repair: Repair the harness or replace the harness.STOPTest Step 3. MEASURE THE RESISTANCE THROUGH THE MJB-ECM HARNESS.
The ECM remains disconnected.
Measure the resistance between CDL+ (pin 7) and the CDL- (pin 6) on the connector for the marine junction box.
Select your engine from Table 2. Continue to test with the combinations of pins that are listed in Table 2.
Table 2
Engine Measure from J1 Pin Number Circuit Name Measure to Circuit name
C9
C12
C15
C18
3126B J1-8 CDL+ J1-9 CDL-
J1-8 CDL+ J1-7
J1-8 CDL+ J1-19
J1-8 CDL+ J1-70 Keyswitch
J1-8 CDL+ J1-52 +Battery
J1-8 CDL+ J1-61 -Battery
J1-9 CDL- J1-10
J1-9 CDL- J1-19
J1-9 CDL- J1-20
J1-9 CDL- J1-70 Keyswitch
J1-9 CDL- J1-52 +Battery
J1-9 CDL- J1-61 -Battery
3124E
C30
C32 J1-3 CDL+ J1-9 CDL −
J1-3 CDL+ J1-2
J1-3 CDL+ J1-8
J1-3 CDL+ J1-23 Keyswitch
J1-3 CDL+ J1-4 +Battery
J1-3 CDL+ J1-5 -Battery
J1-9 CDL- J1-8
J1-9 CDL- J1-14
J1-9 CDL- J1-15
J1-9 CDL- J1-23 Keyswitch
J1-9 CDL- J1-4 +Battery
J1-9 CDL- J1-5 -Battery
3196
3406E J1-3 CDL+ J1-9 CDL −
J1-3 CDL+ J1-2
J1-3 CDL+ J1-8
J1-3 CDL+ J1-6 Keyswitch
J1-3 CDL+ J1-4 +Battery
J1-3 CDL+ J1-5 -Battery
J1-9 CDL- J1-8
J1-9 CDL- J1-14
J1-9 CDL- J1-15
J1-9 CDL- J1-6 Keyswitch
J1-9 CDL- J1-5 +Battery
J1-9 CDL- J1-5 -Battery Expected Result:The resistance is greater than 20000 Ohms.Results:
OK - The resistance is greater than 20000 Ohms. Go to Test Step 4.
NOT OK - The resistance is NOT greater than 20000 Ohms. A short circuit exists.Repair: Repair the harness or replace the harness.STOPTest Step 4. MEASURE THE RESISTANCE THROUGH THE MARINE JUNCTION BOX (OPEN CIRCUIT TEST).
Disconnect the MJB-ECM cable from the MJB.
Disconnect the CDL cable from the marine junction box.
Measure the resistance between the CDL connector and the MJB-ECM cable connector on the marine junction box. Refer to Table 3.
Table 3
Pin on the ECM J3 Interface Connector Circuit Name Measure to CDL Connector Pin Number
21 CDL- 5
22 CDL+ 6 Expected Result:The resistance is less than 10 Ohms.Results:
YES - The resistance is less than 10 Ohms. Go to Test Step