COVER 4N0053 - Caterpillar

Table 1
Diagnostic Codes Table
Code and Description Conditions which Generate this Code System Response
638-02 Engine Power Excessive The actual rack position is greater than the desired rack position. Excessive power is being generated by the engine. The code is logged.
Factory passwords are required to clear this code.
638-05 Rack BTM current low The actual rack position is not proportional to the desired rack position. There are no sensor supply voltage faults. The arm of the rack solenoid is not in the desired position. The code is logged.
The ECM uses the engine speed to govern the engine. The rack sensor signal is ignored. The rack limit is set to 13.5 mm (0.53 inch).
638-06 Rack BTM current high The actual rack position is not proportional to the desired rack position. There are no sensor supply voltage faults. The arm of the rack solenoid is not in the desired position. The code is logged.
The ECM uses the engine speed to govern the engine. The rack sensor signal is ignored. The rack limit is set to 13.5 mm (0.53 inch).
Illustration 1 g03844039Recommended Actions
Table 2
Troubleshooting Test Steps Value Results
1. Inspect the Electrical Connectors and the Wiring Harness.
A. Remove electrical power from the ECM.
B. Thoroughly inspect the J2/P2 connector for the rack solenoid (BTM) and the J11/P11 connector for the rack position sensor. Inspect the ECM connector J2/P2. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
C. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit.
D. Check the allen head screw on the ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Electrical connectors and wiring
Result : The electrical connectors and wiring are OK.
Proceed to Test Step 2.
Result : The electrical connectors and wiring are NOT OK.
Repair : Repair the wiring and connectors or replace the wiring or the connectors. Ensure that all of the seals are properly connected. Verify that the repair eliminates the problem.
If the problem is not resolved, proceed to Test Step 2.
2. Remove the Rack Solenoid and Inspect the Rack Solenoid.
A. Turn the engine control switch to the OFF position.
B. Remove the rack solenoid.
C. Make sure that the rack and the rack servo have free movement.
D. Inspect the arm of the rack solenoid for damage and signs of binding in the sleeve of the servo.
Rack solenoid
Result : The rack solenoid is OK.
Proceed to Test Step 3.
Result : The rack solenoid is NOT OK.
Repair : Repair the arm of the rack solenoid or replace the arm of the rack solenoid.
If the problem is not resolved, proceed to Test Step 3.
3. Sweep Test for the Rack Solenoid.
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Turn the engine control switch to the ON position.
C. Activate the sweep test for the rack solenoid and observe the arm of the rack solenoid.
Note : Some applications may have an auxiliary system that can interrupt power to the ECM. These systems may need to be temporarily bypassed in order