Caterpillar Monitoring System for Electronic Modular Control Panel Caterpillar

Harness Code - Troubleshoot

Usage:

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Table 1
Harness Code Troubleshooting ⁽¹⁾
Main Display Module Connector Contact	31	3	12	22	16	6
Wire Identification	270-BK	271-BK	272-BK	273-BK	274-BK	275-BK
Harness Code Plug Contact ⁽²⁾	1	2	3	4	5	6

engine Code	Specified Status
01	O ⁽³⁾	G ⁽⁴⁾	G	G	G	G
02	G	O	G	G	G	G
03	O	O	G	G	G	G
04	G	G	O	G	G	G
05	O	G	O	G	G	G
06	G	O	O	G	G	G
07	O	O	O	G	G	G
08	G	G	G	O	G	G
09	O	G	G	O	G	G
10	G	O	G	O	G	G
11	O	O	G	O	G	G
12	G	G	O	O	G	G
13	O	G	O	O	G	G
14	G	O	O	O	G	G
15	O	O	O	O	G	G
16	G	G	G	G	O	G
17	O	G	G	G	O	G
18	G	O	G	G	O	G
19	O	O	G	G	O	G
20	G	G	O	G	O	G
21	O	G	O	G	O	G
22	G	O	O	G	O	G
23	O	O	O	G	O	G
24	G	G	G	O	O	G
25	O	G	G	O	O	G
26	G	O	G	O	O	G
27	O	O	G	O	O	G
28	G	G	O	O	O	G
29	O	G	O	O	O	G
30	G	O	O	O	O	G
31	O	O	O	O	O	G
32	G	G	G	G	G	O
33	O	G	G	G	G	O
34	G	O	G	G	G	O
35	O	O	G	G	G	O
36	G	G	O	G	G	O
37	O	G	O	G	G	O
38	G	O	O	G	G	O
39	O	O	O	G	G	O
40	G	G	G	O	G	O
41	O	G	G	O	G	O
42	G	O	G	O	G	O
43	O	O	G	O	G	O
44	G	G	O	O	G	O
45	O	G	O	O	G	O
46	G	O	O	O	G	O
47	O	O	O	O	G	O
48	G	G	G	G	O	O
49	O	G	G	G	O	O
50	G	O	G	G	O	O
51	O	O	G	G	O	O
52	G	G	O	G	O	O
53	O	G	O	G	O	O
54	G	O	O	G	O	O
55	O	O	O	G	O	O
56	G	G	G	O	O	O
57	O	G	G	O	O	O
58	G	O	G	O	O	O
59	O	O	G	O	O	O
60	G	G	O	O	O	O
61	O	G	O	O	O	O
62	G	O	O	O	O	O

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^( 1 )	Main display module is in the Harness Code Mode (Mode 1).
^( 2 )	For engines so equipped. For engines without a harness code plug, permanent harness code connections are in the engine harness.
^( 3 )	O = open
^( 4 )	G = grounded

Before you perform this procedure, determine the engine code by using the harness code mode. The main display module must have the correct part number for the particular engine. If the engine code is not shown correctly, this procedure determines the component that is malfunctioning. This failure could be caused by a failure in the main display module, a wrong harness code plug or a faulty harness.

Note: The harness code and the engine code are similar terms. The codes describe the particular engine. The harness code is the status (open or ground) of the six harness code inputs (connector contacts 3, 6, 12, 16, 22 and 31). The main display module assigns a number to a engine. This number is the engine code. The engine code is shown during harness code mode. Each sales model has a specific harness code. Therefore, each sales model also has a specific engine code. The specific engine code is listed in Systems Operation, "Harness Code Mode". The specific harness code is given in the Electrical System Schematic.

Procedure

Determine the engine code.
1. Determine the engine code.
1. The engine code is listed in Systems Operation, "Harness Code Mode".
1. After you find the engine code, use the table "Harness Code Troubleshooting" in order to find the corresponding specified harness code.
  Results:
  CONTINUE - Proceed to 2.

Check the circuits for the harness code.
1. The remaining tests check for incorrect harness codes on the inputs for the main display module. Compare the status of the harness code that is found in the test "Determine the engine code" to the status at the inputs for the main display module. The table identifies the connector contacts and wire identification of the harness code circuits. Contacts that are specified as grounded contacts should be checked for opens in the harness. Contacts that are specified as open contacts should be checked for shorts in the harness.
  Results:
  - CONTINUE - Proceed to 3.

Check for opens.
1. Turn the ECS to the OFF/RESET position.
1. Disconnect the engine harness from the main display module.
1. Check for continuity between the connector contacts that are grounded contacts and contact 2 (ground). Check for continuity at the engine harness connector for the main display module
  Expected Result: The resistance measures 5.0 Ohms or less.
  Results:
  - YES - The resistance is 5.0 Ohms or less. The circuit for the harness code is not open. No defect was found in the ground circuits for the harness code. Proceed to 4.
  - NO - The resistance is greater than 5.0 Ohms. The circuit for the harness code is open. Check the harness code plug on so equipped engines. Record the open contact of the engine harness connector. Repair the open circuits for the harness code that is found or replace the engine harness. If conditions are not resolved, proceed to 4.

Check for shorts.
1. The ECS remains in the OFF/RESET position. The engine harness to the main display module remains disconnected.
1. Measure the resistance between the connector contacts that are specified as open contacts and contact 2 (ground). Measure the resistance at the engine harness connector for the main display module.
  Expected Result: The resistance measures 5000 Ohms or more.
  Results:
  - YES - The resistance is 5000 Ohms or more. The circuit for the harness code is not shorted to ground. No defect was found in the circuit for the harness code. STOP.
  - NO - The resistance is less than 5000 Ohms. The circuit for the harness code is shorted. Check the harness code plug on so equipped engines. Record the shorted contact of the engine harness connector. Repair the shorted circuits of the harness code that are found or replace the engine harness. If conditions are not resolved, proceed to 5.

Check if the fault remains.
1. Reconnect the harness connectors.
1. Turn the ECS to the COOLDOWN/STOP position.
1. Recheck the engine code.
  Expected Result: The main display module shows the correct engine code.
  Results:
  - YES - The main display module shows the correct engine code. STOP.
  - NO - The main display module does not show the correct engine code. Replace the module. Refer to Testing and Adjusting, "Module - Replace".
  Results:
  - OK - STOP.