17841-ZW9-830 Honda ROD, THROTTLE (Honda Code 6639835).

The ECM limits the flow of fuel to prevent the engine speed from exceeding the value that is programmed into the ECM.If the engine speed exceeds the value that is programmed into the ECM, the ECM illuminates the warning lamp and the shutdown lamp. A 190-0 code becomes active for the current keyswitch cycle. When the keyswitch is cycled to the OFF position and back to the ON position, the 190-0 code becomes logged.The history of engine overspeeds can be viewed on the electronic service tool.Probable Causes
Diagnostic codes
Proceeding down steep grades (if applicable)
Extended idle times
Engine crankcase breather
Turbocharger
Combustible gases or liquid in the Intake airRecommended 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. Download 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.
B. Use the electronic service tool to check for active or logged codes.
Diagnostic codes
Result: A diagnostic code is not active or logged.
Return the unit to service.
Result: A 190-0 diagnostic code is present.
Proceed to Test Step 2.
2. Proceeding Down Steep Grades (If Applicable)
Engaging the engine brakes on a steep grade may be necessary. Not all applications have engine brakes.
A. Make sure that the operator understands the correct operation of the machine while using the engine brakes.
Steep grades
Result: Steep grades are the cause of the overspeed.
Repair: Control the engine speed during steep grades. Running in this operating mode or rolling of the machine can cause the crankcase breather to fill with oil. This leads to oil leaking into the turbocharger.
Proceed to Test Step 3.
Result: Steep grades are not the cause of the overspeed.
Proceed to Test Step 3.
3. Extended Idle Times
A.Engines spending excessive time at idle with little load can lead to oil carryover. This could lead to overspeed. Refer to Operation and Maintenance Manual, Operation Section.
Idle times
Result The idle times are extensive.
Reduce the idle times.
Proceed to Test Step 4.
Result The idle times are not extensive.
Proceed to Test Step 4.
4. Engine Crankcase Breather
A. Check the engine crankcase breather for blockage or restrictions.
B. Check for excessive oil from the outlet of the breather.
C. Check that the application has not been operated above the recommended gradient.
D. Check if the Oil Mist Separator drain hose is fitted using correct orientation (white mark facing OMS drain spigot).
E. Check to see whether an OMS filter is fitted.
Breather
Result: The engine crankcase breather is blocked or restricted.
Repair: Clear the blockage or restriction.
Result: Excessive oil is ejected from the outlet of the breather.
Repair: Investigate the cause of the excessive oil content in the breather flow. Check that the engine has been serviced in line with the recommended maintenance intervals. Refer to Operation and Maintenance Manual, if above 1500 hours, change the crankcase breather filter. Refer to Operation and Maintenance Manual, Crankcase Breather (Canister) - Replace.
Note: Some oil presence from the breather is normal.
Proceed to Test Step 5.
Result: Little or no oil is ejected through the breather.
Repair: Clean oil from hoses and retest.
Proceed to Test Step 5.
5. Turbocharger
Note: The turbocharger that is installed on the engine is a nonserviceable item. If any mechanical fault exists, then the faulty turbocharger must be replaced.
A. Check for any oil that may be leaking into the intake air.
Turbocharger
Note: Some oil residue/pooling may be seen, but this is not an indication that the turbo has failed. If the compressor and turbine blades are undamaged and rotate freely, it is likely the turbocharger is fault free.
Result: The turbocharger is leaking oil into the intake air.
Repair: Replace the faulty turbocharger.
Proceed to Test Step 6.
Result: A turbocharger is not leaking oil into the intake air.
Proceed to Test Step 6.
6. Combustible Gases or Liquid in the Intake Air
A. Check for combustible gases in the surrounding atmosphere.
B. Check for combustible liquid in the air intake.
Air quality
Result: The atmosphere has combustible gases.
Do not operate the engine in an environment with combustible gases.
Result: There is combustible liquid in the air intake.
Repair: Remove the liquid. Investigate and rectify the cause of liquid ingestion
Result: The intake air does not contain combustible gases.
Contact the Dealer Solutions Network (DSN).