817960A 2 Force TOWERSHAFT W/SWIVEL, BEARINGS AND SCREWS

Table 1
Diagnostic Codes    
CDL Code     J1939 Code     Code Description
(code descriptions may vary)     Comments    
2533-5     1072-5     Compression Brake Low/High Solenoid #1 : Current Below Normal     The code is logged when there is an electrical or wiring problem with the brake assemble positioned over cylinder 3 and cylinder 4.    
2533-6     1072-6     Compression Brake Low/High Solenoid #1 : Current Above Normal     The code is logged when there is an electrical or wiring problem with the brake assemble positioned over cylinder 3 and cylinder 4.    
2535-5     1073-5     Compression Brake Medium/High Solenoid #1 : Current Below Normal     The code is logged when there is an electrical or wiring problem with the brake assembles positioned over cylinders 1 and 2 or cylinders 5 and 6.    
2535-6     1073-6     Compression Brake Medium/High Solenoid #1 : Current Above Normal     The code is logged when there is an electrical or wiring problem with the brake assembles positioned over cylinders 1 and 2 or cylinders 5 and 6.    The compression brake uses the engine in order to provide auxiliary braking for the machine. The compression brake reduces wear of the wheel brake components, brake oil temperature, and the chance for engine overspeed. The compression brake also aids in the controllability of the machine.The CAT Compression Brake consists of identical housing assemblies. Each housing assembly is positioned over two cylinders. The Low braking function is accomplished by activating the middle brake assembly. The middle brake assembly is positioned over cylinders 3 and 4. The Medium braking function is accomplished by activating the outside two brake assemblies. The outside brake assemblies are located over cylinders 1 and 2 and cylinders 5 and 6. The High braking function is accomplished by activating all the brake assemblies. The braking level (Low, Medium, or High) is application-specific, therefore some applications may not have all three levels.If the retarder is installed on the engine, the configuration parameter for the engine retarder must be set to "Enabled" for this function to operate. The engine ECM will activate the appropriate compression brake solenoids in order to meet the requested level of braking. "Compression Brake Solenoid Override"
The Compression Brake Low/High Override activates the brake on cylinders 3 and 4
The Compression Brake Med/High Override activates the brakes on cylinders 1 and 2 and cylinders 5 and 6The Compression Brake Low/High Override and Compression Brake Med/High Override are diagnostic overrides that are available on Caterpillar Electronic Technician (ET). Use the overrides to assist in troubleshooting problems in the circuit for the compression brake. The ECM will only detect shorts in the circuit for the compression brake when the overrides are active. The overrides must be activated and then deactivated before the ECM will detect an open circuit. The ECM will only detect opens in the circuit for the compression brake when the overrides are not active.Note: The engine speed must be zero before the overrides will function.
Illustration 1 g01199118
Location of the compression brake solenoid (typical example)
Illustration 2 g03029438
Schematic for the compression brake circuit
Table 2
Troubleshooting Test Steps    Values    Results    
1. Check for Active Diagnostic Codes and/or Logged Diagnostic Codes
A. Connect Cat ET to the service tool connector.
B. Turn the keyswitch to the ON position.
C. Access the diagnostic overrides under the "Diagnostics" menu.
D. Start the "Compression Brake Low/High Override" on Cat ET.
E. Once Cat ET displays the status of the compression brake solenoid, stop the "Compression Brake Low/High Override".
F. Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes.
G. Start the "Compression Brake Med/High Override" on Cat ET.
H. Once Cat ET displays the status of the compression brake solenoid, stop the "Compression Brake Med/High Override".
I. Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes.
   
Diagnostic Trouble codes    
Result: A 2533-5, 2535-5, 1072-5 or a 1073-5 diagnostic code is active at this time. If both diagnostic codes are active, the problem is most likely in the shared return wire. Inspect the wire and/or connectors for an open circuit.
Proceed to Test Step 2.
Result: A 2533-6, 2535-6, 1072-6 or a 1073-6 diagnostic code is active at this time.
Proceed to Test Step 4.
   
2. Create a Short Between the Wires of the Suspect Compression Brake Solenoid at the Valve Cover Connector
In order to troubleshoot a 2533-5 or 1072-5 diagnostic code, use the "Compression Brake Low/High Override" on Cat ET. In order to troubleshoot a 2535-5 or 1073-5 diagnostic code, use the "Compression Brake Med/High Override" on Cat ET.
A. Turn the keyswitch to the OFF position.
B. Disconnect the harness at the valve cover connector.
C. Fabricate a jumper wire in order to create a short between the supply wire for the suspect compression brake solenoid and engine ground.
D. Turn the keyswitch to the ON position.
E. Access the diagnostic overrides under the "Diagnostics" menu.
F. Start the override for the compression brake.
G. Once Cat ET displays the status of the compression brake solenoid, stop the override.
H. Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes.
I. Turn the keyswitch to the OFF position. Remove the wire short.
A -5 open circuit diagnostic code will be active for the other compression brake solenoid. Ignore the diagnostic codes for the other compression brake solenoid. Ignore any diagnostic codes for the injector solenoids.
   
Short circuit detected
   
Result: A 2533-6, 1072-6, 1073-6 or a 2535-6 diagnostic code is active at this time. The ECM detected the short at the valve cover connector. The harness wiring between the valve cover connector and the ECM is OK.
Proceed to Test Step 3.
Result: A 2533-5, 1072-5, 1073-5 or a 2535-5 diagnostic code is active at this time. The ECM did not detect the short at the valve cover connector.
Repair the harness or replace the harness. Verify that the problem is resolved.
   
3. Create a Short Circuit at the Compression Brake Solenoid
Two solenoids are activated in order to create a medium braking action. The open could