Marine Multi-Station Control System Caterpillar

This procedure is used in order to test the Cat data link ("CDL") circuit.

Test Step 1. INSPECT ELECTRICAL CONNECTORS AND WIRING.

1. Turn the keyswitch to the OFF position.

2. 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.

  STOP

Test Step 2. MEASURE THE RESISTANCE THROUGH THE "MJB-ECM" J3 HARNESS.

1. Disconnect the ECM from the engine harness.

2. Disconnect the "MJB-ECM" J3 connector from the marine junction box.

3. Install a jumper between the ECM CDL+ and CDL- wires. Refer to table 1.

4. 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.

  STOP

Test Step 3. MEASURE THE RESISTANCE THROUGH THE MJB-ECM HARNESS.

1. The ECM remains disconnected.

2. Measure the resistance between CDL+ (pin 7) and the CDL- (pin 6) on the connector for the marine junction box.

3. Select your engine from Table 2. Continue to test with the combinations of pins that are listed in Table 2.
   Show/hide table

   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.

  STOP

Test Step 4. MEASURE THE RESISTANCE THROUGH THE MARINE JUNCTION BOX (OPEN CIRCUIT TEST).

1. Disconnect the MJB-ECM cable from the MJB.

2. Disconnect the CDL cable from the marine junction box.

3. Measure the resistance between the CDL connector and the MJB-ECM cable connector on the marine junction box. Refer to Table 3.
   Show/hide table

   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 5.

• NO - The resistance is NOT less than 10 Ohms. There is an open circuit in the marine junction box.

  Repair: Temporarily replace the marine junction box. Recheck to ensure the resistance is less than 10 Ohms.

  STOP

Test Step 5. MEASURE THE RESISTANCE THROUGH THE MARINE JUNCTION BOX (SHORT CIRCUIT TEST).

1. The MJB-ECM harness remains disconnected.

2. The CDL cable remains disconnected from the marine junction box.

3. Measure the resistance between the pins that are listed in Table 4.
   Show/hide table

   Table 4

   Measure from J3 Marine Junction Box Pin Number	Circuit Name	Measure to MJB Pin Number	Circuit Name
   21	CDL+	10	+Hour meter
   21	CDL+	11	-Tachometer
   21	CDL+	12	+Tachometer
   21	CDL+	20	Remote shutdown switch
   21	CDL+	28	Unswitched +battery
   21	CDL+	29	-Battery
   21	CDL+	30	-Battery
   21	CDL+	18	Keyswitch
   22	CDL-	11	-Tachometer
   22	CDL-	12	+Tachometer
   22	CDL-	13	Indicator for low oil pressure
   22	CDL-	23	CAN data shield
   22	CDL-	29	-Battery
   22	CDL-	30	-Battery
   22	CDL-	31	-Battery
   22	CDL-	18	Keyswitch
   22	CDL-	26	+Battery

Expected Result:

The resistance is less than 10 ohms.

Results:

• YES - The resistance is less than 10 ohms. Go to Test Step 6.

• NO - The resistance is greater than 10 ohms. There is an open circuit in the marine junction box.

  Repair: Temporarily replace the marine junction box. Recheck to ensure the resistance is less than 10 Ohms.

  STOP

Test Step 6. MEASURE THE RESISTANCE THROUGH THE CDL DATA RUN (OPEN CIRCUIT TEST).

1. Disconnect the CDL cable from the marine junction box.

2. Disconnect all displays from the CDL and disconnect all service tools from the CDL.

3. Install a jumper between pin 5 and pin 6 on the CDL connector to the marine junction box.

4. Measure the resistance between the CDL+ (Pin D) and the CDL- (Pin E) on the CDL connector to the marine junction box. Wiggle the harness during the measurement in order to reveal an intermittent condition.

Expected Result:

The resistance is less than 20 Ohms.

Results:

• OK - The resistance is less than 20 Ohms. Go to Test Step 7.

• NOT OK - The resistance is greater than 20 Ohms.

  Repair: Repair the harness or replace the harness.

  STOP

Test Step 7. MEASURE THE RESISTANCE THROUGH THE CDL (SHORT CIRCUIT TEST).

1. Disconnect the CDL cable from the marine junction box.

2. Disconnect all displays and service tools from the CDL.

3. Remove the jumper that was installed in the previous step.

4. Measure the resistance between pin D and pin E on the CDL connector according to Table 5. Wiggle the harness during the measurement in order to reveal an intermittent condition.
   Show/hide table

   Table 5

   CDL Connector Pin Number	Circuit Name	Measure to Pin Number	Circuit Name
   5	CDL-	1	Keyswitch
   5	CDL-	2	-Battery
   5	CDL-	3	Port keyswitch
   5	CDL-	4	Starboard keyswitch
   5	CDL-	6	CDL+
   6	CDL+	1	Keyswitch
   6	CDL+	2	-Battery
   6	CDL+	3	Port keyswitch
   6	CDL+	4	Starboard keyswitch
   6	CDL+	5	Keyswitch

Expected Result:

The resistance is greater than 20000 Ohms.

Results:

• OK - The resistance is greater than 20000 Ohms.

  Repair: Temporarily replace the faulty display. Recheck in order to ensure the resistance is greater than 2000 Ohms.

  STOP

• NOT OK -

  Repair: Repair the harness or replace the harness.

  STOP