0391036 JOHNSON KNOB & FRICTION ADJ. SCREW ASSY.

Table 1
J1939 Code and Description CDL Code and Description Comments
1656-2
Engine Automatic Start Enable Switch : Erratic, Intermittent, or Incorrect 336-2
Engine Control Switch : Erratic, Intermittent, or Incorrect The two inputs from the Electronic Control Switch (ECS) are in the opposite state.
The code is logged.
Illustration 1 g06344373
Table 2
Troubleshooting Test Steps Values Results
1. Inspect the Electrical Connectors and the Wiring
A. Turn the main disconnect switch to the OFF position.
B. Thoroughly inspect the connectors. Refer to Troubleshooting, "Electrical Connectors-Inspect" for additional information.
C. Perform a 45 N (10 lb) pull test on the connector wires.
D. Check the harness for abrasions and pinch points.
Connectors and Wiring
Result: The connectors and/or wiring appear to be OK.
Proceed to Test Step 2.
Result: There is a problem with the connectors and/or wiring.
Repair: Repair and/or replace the connectors or wiring. Ensure that all the seals are properly in place and ensure that the connectors are coupled.
If the problem is not resolved, proceed to Test Step 2.
2. Check the Status of the Switch Position
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Use Cat ET to monitor the status of the following switch:
- Start/Run/Stop switch
C. Turn the Start/Run/Stop switch to the following position:
- STOP position
- Start position
- STOP position
Switch Status
Result: The parameter for the switch is not correct in either the STOP or the START positions.
Proceed to Test Step 3.
Result: The status for the switch is correct in both the START and STOP positions. A code for the switch is not active.
Repair: The switch appears to be operating correctly. There may be an intermittent problem in the harness or in a connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for additional information.
If the problem is not resolved, proceed to Test Step 3.
3. Check the Wiring for an Open Circuit
A. Turn the main disconnect switch to the OFF position.
B. Disconnect the engine interface connector (EC-5) from the wiring harness connectors.
C. Remove the wires from the switch.
D. Install a jumper wire between the following wires at the switch:
- R755-BK
- R776-BK
E. Measure the resistance between the following terminals at the engine interface connector (EC-5):
- Pin 46 and Pin 5 on the EC-5 connector
- Pin 47 and Pin 5 on the EC-5 connector
F. Return all wiring to the original configuration.
Open Circuit
Result: There were less than 10 ohms of resistance on between each of the pins.
Proceed to Test Step 4.
Result: There were more than 10 ohms of resistance on between each of the pins.
Repair: An open circuit has been detected. Repair and/or replace the wiring harness.
If the problem is not resolved, proceed to Test Step 4.
4. Check the Wiring for a Short Circuit to Ground
A. Disconnect the engine interface connector (EC-5).
B. Install a jumper wire between the following wires at the switch:
- R755-BK
- R776-BK
C. Measure the resistance between the following:
- Pin 46 the EC-5 connector and Engine ground
- Pin 47 on the EC-5 connector and Engine ground
D. Return all wiring to the original configuration.
Short Circuit
Result: There were more than 100K ohms of resistance between each of the pins and ground.
Proceed to Test Step 5.
Result: There were less than 100K ohms of resistance between each of the pins and ground.
Repair: A short circuit to ground has been detected. Repair and/or replace the wiring harness.
If the problem is not resolved, proceed to Test Step 5.
5. Check the Wiring for a Pin to Pin Short Circuit
A. Disconnect the engine interface connector (EC-5).
B. Install a jumper wire between the following wires at the switch:
- R755-BK
- R776-BK
C. Measure the resistance between the following:
- Pin 46 the EC-5 connector and all other pins on the EC-5 Connector
- Pin 47 on the EC-5 connector and all other pins on the EC-5 Connector
Note: There will be continuity with pin 46/47 and pin 5 when performing this test.
D. Return all wiring to the original configuration.
Short Circuit
Result: There were more than 100K ohms of resistance between each of the pins and all other pins except pin 5 on the EC-5 connector.
Proceed to Test Step 6.
Result: There were less than 100K ohms of resistance between each of the pins and one or more pins except pin 5 on the EC-5 connector.
Repair: A pin to pin short circuit has been detected in the wiring harness connector. Repair and/or replace the wiring harness.
If the problem is not resolved, proceed to Test Step 6.
6. Check the Start/Run/Stop Switch
A. Ensure that the switch is not activated.
B. Measure the resistance between the normally open terminals at the switch.
C. Activate the switch.
D. Measure the resistance between the normally open terminals at the switch.
Note: The resistance measurement indicates an open circuit when the switch is in the STOP position. The resistance measurement indicates a short circuit when the switch is in the START position.
Switch
Result: The resistance measurement indicates an open circuit when the switch is in the STOP position. The resistance measurement indicates a short circuit when the switch is in the START position. The switch is OK.
Return to service.
Result: The resistance measurements are not correct.
Repair: Replace the start/run/stop switch.
Procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).