CAP AS-TRACK IDLER 1311641 - Caterpillar

This procedure covers the following diagnostic trouble codes:
Table 1
Diagnostic Trouble Codes for Fuel Rail Pressure    
J1939 Code    Description    Information    
157-15     Engine Injector Metering Rail 1 Pressure : High - Least Severe (1)     The engine is running. There are no active codes for the fuel rail pressure sensor, for the fuel injection pump, or for the fuel injectors. The fuel rail pressure is excessive. The code is logged. Engine power is derated. Vehicle speed is limited to
72 km/h (45 mph). The derates are removed when power to the Engine Control Module (ECM) is cycled. The following conditions can cause this code:
There is an intermittent open circuit in the wiring for the fuel rail pressure sensor.
There is a problem with the high pressure fuel system. The "Fuel System Functional Test" must be used to determine the problem.    
157-7     Engine Injector Metering Rail 1 Pressure : Not Responding Properly     The engine is running. There are no active codes for the fuel rail pressure sensor, for the fuel injection pump, or for the fuel injectors. The fuel rail pressure is incorrect. The code is logged. Engine power is derated. Vehicle speed is limited to
72 km/h (45 mph). The derates are removed when power is cycled to the ECM. The following conditions can cause this code:
There is an intermittent open circuit in the wiring for the fuel rail pressure sensor.
There is a problem with the high pressure fuel system. The "Fuel System Functional Test" must be used to determine the problem.    
Follow the troubleshooting procedure in order to identify the root cause of the problem.    Troubleshooting ProcedureNote: The troubleshooting procedure is identical for both codes.
If maintenance was just performed on the fuel system, check the work that was performed. Look for these conditions:
Electrical connectors not connected.
Loose fuel lines
The high pressure fuel pump is not correctly timed.
Select the Active Code Wiggle Test by selecting the following menu options:
"Diagnostics"
"Diagnostic Tests"
"Wiggle Test"
Start the test. Any new diagnostic trouble codes will be indicated in red.
Monitor the screen while you wiggle each wire at the sensor's connector. Also, perform a 10 pound pull test on each wire.Repair any problems.
Perform the "Fuel System Functional Test". Cat ET will display an error message that indicates the problem. Follow the repair procedure for the error message:"Fuel Pump Not Timed Correctly" - Remove the high pressure fuel pump and install the high pressure fuel pump. Then, run the "Fuel System Functional Test" in order to verify that the pump is timed correctly."Fuel Pump Flow Too Low" - Replace the high pressure fuel pump. Then, run the "Fuel System Functional Test" again in order to verify that the problem is resolved."Fuel Rail High Pressure Decay Too High" - Replace the pressure relief valve. Then, run the "Fuel System Functional Test" again in order to verify that the problem is resolved. If the problem is not resolved, replace the high pressure fuel pump."Fuel Rail Low Pressure Decay Too High" - Perform the procedure