Wednesday, February 25, 2009

Indicator Lamp for Retarder Does Not Illuminate During the Power Up Self Test


Indicator Lamp for Retarder Does Not Illuminate During the Power Up Self Test


System Operation Description:

The indicator lamp should illuminate for 3 seconds upon powering up.




Schematic of the retarding indicator lamp

Test Step 1. CHANGE THE INDICATOR LAMP

1. Turn the disconnect switch and the key start switch to the OFF position.
2. Replace the retarding indicator lamp with a similar indicator lamp that is known to be correct.
3. Turn the disconnect switch and the key start switch to the ON position.
4. Observe the retarding indicator lamp.

Expected Result:

The retarder indicator lamp illuminates during powering up.

Results:

* OK - The retarder indicator lamp illuminated.

Repair: The indicator is operating properly at this time.

Stop.

* NOT OK - The retarder indicator lamp did not illuminate. Proceed to Test Step 2.

Test Step 2. CHECK THE VOLTAGE AT THE ECM

1. Turn the disconnect switch and the key start switch to the OFF position.
2. Disconnect the machine harness from the brake ECM.
3. Turn the disconnect switch and the key start switch to the ON position.
4. At the machine harness connector for the brake ECM, measure the voltage between connector J1-1 wire (176-OR) and frame ground.

Expected Result:

The voltage should be above 20.5 VDC.

Results:

* OK - The voltage is greater than 20.5 VDC. Proceed to Test Step 3.
* NOT OK - The voltage is less than 20.5 VDC.

Repair: Clean all connections in the wiring harness.

Stop.

Test Step 3. CHECK THE LAMP CIRCUIT

1. Turn the disconnect switch and the key start switch to the OFF position.
2. Install a jumper wire from connector J1-1 wire (176-OR) to connector J1-4 wire (454-GN).
3. At the machine harness connector for the brake ECM, connect J1-15 wire (J766-PU) to frame ground.
4. Turn the disconnect switch and the key start switch to the ON position.

Expected Result:

The indicator lamp illuminates.

Results:

* OK - The indicator lamp illuminates.

Repair: The ECM is very unlikely to fail. Reconnect all connectors and verify that the lamp does not illuminate. Replace the brake ECM after verifying that the problem is still existing. See Testing And Adjusting, "Electronic Control Module (ECM) - Replace".

Stop.

* NOT OK - The indicator lamp did not illuminate.

Repair: The wire harness has failed. Repair the wire harness or replace the wire harness.

Stop.
»»  read more

Sunday, February 15, 2009

Configurations for the Brake Electronic Control System

There are three possible configurations for the Brake Electronic Control System.
• Integrated Brake Electronic Control (Automatic Retarder Control and the Traction Control System)
• Automatic Retarder Control (ARC) only
• Traction Control System (TCS) only
Each machine configuration uses a separate ECM. Each ECM has an individual part number. Also, each ECM requires a separate FLASH software in order to instruct the ECM about the machine configuration. A separate part number is available for each FLASH software for each ECM.
The brake ECM determines whether the service/retarder brakes should engage for the function of the Automatic Retarder Control (ARC). This action is accomplished by sending signals to the various components of the ARC.
The brake ECM determines whether the parking and secondary brakes should engage for the function of the Traction Control System (TCS). This action is accomplished by sending signals to the various components of the TCS.
The brake ECM also provides the service technician with enhanced diagnostic capabilities. This is available through the use of onboard memory. Onboard memory stores the possible diagnostic codes for retrieval at the time of service. Service personnel should use the Electronic Technician service tool (ET) for troubleshooting.
The following modules communicate with each other through the CAT data link: the engine ECM, the transmission/chassis ECM, the monitoring system and the brake ECM. Communication between the electronic controls allows the sensors of each system to share information.
»»  read more

Monday, February 9, 2009

Indicator Lamp for Retarder Is On Continuously

Indicator Lamp for Retarder Is On Continuously

System Operation Description:

The indicator lamp should illuminate for 3 seconds upon powering up.


Test Step 1. CHECK THE LAMP CIRCUIT

1. Turn the disconnect switch and the key start switch to the OFF position.
2. Disconnect the machine harness from the brake ECM.
3. At the machine harness connector for the brake ECM, connect J1-15 wire (J766-PU) to frame ground.
4. Turn the disconnect switch and the key start switch to the ON position.

Expected Result:

The indicator lamp should not illuminate.

Results:

* OK - The indicator lamp did not illuminate. Proceed to Test Step 2.
* NOT OK - The indicator lamp illuminates.

Repair: The wire harness is shorted to battery voltage. Repair the wire harness or replace the wire harness.

Stop.

Test Step 2. CHECK THE WIRE FOR THE INDICATOR LAMP

1. Turn the disconnect switch and the key start switch to the OFF position.
2. Remove the lamp from the socket.
3. At the machine harness connector for the brake ECM, check the resistance from J1-15 wire (J766-PU) to all contacts on connector J1 and J2.

Expected Result:

The resistance should be greater than 5000 Ohms.

Results:

* OK - The resistance is greater than 5000 Ohms.

Repair: The ECM is very unlikely to fail. Reconnect all connectors and verify that the lamp is still illuminated. Replace the brake ECM after verifying that the problem is still existing. See Testing And Adjusting, "Electronic Control Module (ECM) - Replace".

Stop.

* NOT OK - The resistance is less than 5000 Ohms on one of the readings.

Repair: The wire harness is shorted to battery voltage. Repair the wire harness or replace the wire harness.

Stop.
»»  read more