12251-881-850 Honda SEE PART DETAILS - SUP; GASKET, CYLINDER HEAD (Honda Code 3738846).

Probable Causes
Diagnostic codes
ECM parameters
Accessory and/or parasitic loads
Flash file
Throttle signal
Air intake and exhaust system
Turbocharger
Fuel supply
Low compression (cylinder pressure)
Electronic unit injectors
Individual malfunctioning cylinders
Table 1
Associated Diagnostic Trouble Codes
J1939 Code CDL Code
157-18 E398 (2) Recommended Actions
Note: The procedures have been listed in order of probability. Complete the procedures in order.
Table 2
Troubleshooting Test Steps Values Results
1. Diagnostic Codes
A. Establish communication between the electronic service tool and the Electronic Control Module (ECM). Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Download the Warranty Report and the Product Status Report with Histograms before performing any troubleshooting or clearing any diagnostic codes.
Note: The downloaded information will be required by the Dealer Solutions Network (DSN) if troubleshooting assistance is needed.
C. Use the electronic service tool to check for active or logged codes.
Diagnostic codes
Result: There are active or logged codes.
Repair: Troubleshoot any codes before continuing with this procedure.
Result: There are no active or logged codes.
Proceed to Test Step 2.
2. ECM Parameters
A. Use the electronic service tool to verify that the correct engine parameters are being used. Refer to Troubleshooting, "Configuration Parameters" for additional information.
B. If applicable, verify that all parameters for any parasitic loads are correct.
Parameters
Result: The parameters are not configured correctly.
Repair: Correctly configure the parameters.
Verify that the configuration change eliminated the fault.
Result: The parameters are configured correctly.
Proceed to Test Step 3.
3. Accessory and/or Parasitic Loads
A. Check all accessory equipment for problems that may create excessive load on the engine.
B. Check for any excess parasitic load on the engine.
Parasitic loads
Result: There is an excessive load on the engine.
Repair: Diagnose and repair the fault.
Verify that the repair eliminated the fault.
Result: There is not an excessive load on the engine.
Proceed to Test Step 4.
4. Flash File
A. Verify that the latest flash file is installed in the Electronic Control Module (ECM). Refer to Troubleshooting, "ECM Software - Install" for the correct procedure.
Flash file
Result: The latest flash file is not installed in the ECM.
Repair: Install the latest flash file. Verify that the repair eliminated the fault.
Result: The latest flash file is installed in the ECM.
Proceed to Test Step 5.
5. Throttle Signal
A. Use the electronic service tool and observe the throttle signal. Make sure that the throttle reaches the 100% raw position and the calibrated position.
CAN data link
Result: The throttle signal is erratic or does not reach the 100% raw position or the calibrated position.
Repair: Refer to the appropriate circuit test for the type of throttle that is installed.
Result: The throttle signal is OK.
Proceed to Test Step 6.
6. Air Intake and Exhaust System
A. Check the air filter restriction indicator, if equipped.
B. Check the air inlet and exhaust system for restrictions and/or leaks.
Restrictions
Result: The air filter is plugged.
Repair: Clean or replace the air filter. Refer to the Operation and Maintenance Manual for further information.
Result: There are restrictions in the air inlet or exhaust system.
Repair: Make the necessary repairs, Verify that the repair eliminated the fault.
Result: There are no restrictions in the air inlet or exhaust system.
Proceed to Test Step 7.
7. Turbocharger
A. Check for the correct operation of the turbocharger or turbochargers.
Turbocharger
Result: The turbocharger is not operating correctly.
Repair: Repair or replace the faulty turbocharger. Verify that the repair eliminated the fault.
Result: The turbocharger is operating correctly.
Proceed to Test Step 8.
Contact with high pressure fuel may cause fluid penetration and burn hazards. High pressure fuel spray may cause a fire hazard. Failure to follow these inspection, maintenance and service instructions may cause personal injury or death.
Contact with high-pressure fuel may cause personal injury or death. Wait 10 minutes after the engine has stopped to allow fuel pressure to purge before any service or repair is performed on the engine fuel lines.
Table 3
Troubleshooting Test Steps Values Results
8. Fuel Supply
A. Check for leaks from the high-pressure fuel lines.
B. Ensure that the vent in the fuel cap is not filled with debris.
C. Ensure that the fuel supply valve (if equipped) is in the full OPEN position.
D. If the temperature is below 0 °C (32 °F), check for solidified fuel (wax).
E. Check the primary filter/water separator for water in the fuel.
F. Check for fuel supply lines that are restricted.
G. Replace the primary and secondary fuel filters.
H. Check the diesel fuel for contamination. Refer to Systems Operation, Testing, and Adjusting, "Fuel Quality - Test".
I. Check for air in the fuel system. Refer to Systems Operation, Testing, and Adjusting, "Air in Fuel - Test".
Fuel system
Result: There is a leak from a high-pressure fuel line.
Repair: Replace the high-pressure fuel line. Refer to Disassembly and Assembly, "Fuel injection lines - Remove" and Disassembly and Assembly, "Fuel injection lines - Install".
Result: The vent in the fuel cap is blocked.
Repair: Install a replacement fuel cap.
Result: The fuel contains solidified wax.
Repair: Replace the fuel with fuel of the correct specification for the ambient conditions.
Result: There are fuel supply lines that are restricted.
Repair: Replace any damaged or restricted fuel lines.
Replace the primary fuel filter and the secondary fuel filters. Refer to the Operation and Maintenance Manual for further information.
Result: There is air in the fuel system.
Repair: Prime the fuel system. Refer to Systems Operation, Testing, and Adjusting, "Fuel System - Prime".
Result: The diesel fuel is contaminated.
Repair: Drain the fuel tank and the fuel system.
Replace the primary fuel filter and the secondary fuel filters. Refer to the Operation and Maintenance Manual for further information.
Fill and prime the fuel system with fuel of the correct specification. Refer to Systems Operation, Testing, and Adjusting, "Fuel System - Prime".
Result: The fuel supply is OK.
Proceed to Test Step 9.
9. Low Compression (Cylinder Pressure)
A. Perform a compression test. Refer to Systems Operation, Testing, and Adjusting, "Compression - Test ".
Cylinde