IllustrationMOTOR HOME BY MONACO BROKEN FRAME TRAILING ARMS. *TR
2006 Monaco Coach Diplomat
Owner reports · Recalls · Investigations
Limited comparison data
There is not enough comparable history to draw a useful model-year comparison.
About this comparison →How this year compares
Owner complaints by model year
Compare all Diplomat years →Counts vary with age, sales and reporting. They are not failure rates.
What owners reported most
Tap a category to read its complaints. One report may name several components.
When problems were reported
Mileage at the reported incident
Limited mileage data: 2 of 4 reports include usable mileage. There isn’t enough coverage to show a useful chart.
NHTSA’s mileage field refers to the reported incident, not necessarily the filing date. This shows report counts, not the likelihood of a failure.
What to inspect
Issues worth paying extra attention to based on owner reports.
- Engine And Engine Cooling. Review the 3 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
- Fuel System, Gasoline. Review the 1 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
- Structure. Review the 1 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
NHTSA owner reports · September 18, 2026 snapshot.
0 crash reports0 fire reports0 injury reports
What owners actually said
4 reportsOWNER OF A 2006 40' MONACO DIPLOMAT RV MOTORHOME DELIVERED WITH A 400HP DIESEL ENGINE, MANUFACTURED BY CUMMINS INC. RECEIVED A RECALL NOTICE RE A POSSIBLE ENGINE FAILURE; HE IS REQUESTING HELP IN ORDERING CUMMINS TO INSTALL A PROPER MANUFACTURED ENGINE. *KB THE CONSUMER STATED THE REMEDY THE MANUFACTURING IS SUGGESTING IS A WA…
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OWNER OF A 2006 40' MONACO DIPLOMAT RV MOTORHOME DELIVERED WITH A 400HP DIESEL ENGINE, MANUFACTURED BY CUMMINS INC. RECEIVED A RECALL NOTICE RE A POSSIBLE ENGINE FAILURE; HE IS REQUESTING HELP IN ORDERING CUMMINS TO INSTALL A PROPER MANUFACTURED ENGINE. *KB THE CONSUMER STATED THE REMEDY THE MANUFACTURING IS SUGGESTING IS A WARNING DEVICE NOT AN ACTUAL FIX TO THE PROBLEM. THE MANUFACTURED STATED THEY WOULD INSTALL A PRESSURE SENSOR IN THE CRANKCASE ESSENTIALLY TO WARN OF A PENDING ENGINE FAILURE.*JB
RECALL BY CUMMINS ON ISL850 ENGINES INSTALLED ON 2006/7 MONACO MOTORHOMES. THE RECALL DOES NOT ADDRESS THE POSSIBLE ENGINE FAILURE ISSUE. IT ONLY PROTECTS THE ENGINE FROM BLOWING UP THUS SAVING CUMMINGS MONEY. THE CORRECT FIX SHOULD BE A NEW ENGINE WHICH WOULD NOT HAVE THE UNCERTAINTY OF ENGINE FAILURE CAUSING THE VEHICLE (MOTO…
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RECALL BY CUMMINS ON ISL850 ENGINES INSTALLED ON 2006/7 MONACO MOTORHOMES. THE RECALL DOES NOT ADDRESS THE POSSIBLE ENGINE FAILURE ISSUE. IT ONLY PROTECTS THE ENGINE FROM BLOWING UP THUS SAVING CUMMINGS MONEY. THE CORRECT FIX SHOULD BE A NEW ENGINE WHICH WOULD NOT HAVE THE UNCERTAINTY OF ENGINE FAILURE CAUSING THE VEHICLE (MOTORHOME ) TO BE STRANDED. *TR UPDATED 09/18/07.*JB
WHILE TRAVELING IN MONTANA IN OUR 2006 MONACO DIPLOMAT MOTORHOME WITH THE CUMMINS ISL400 ENGINE A FUEL LEAK DEVELOPED IN THE ENGINE. THIS LEAK INVOLVED THE LINE FROM THE FUEL PUMP TO THE FUEL RAIL SPRAYING DIESEL FUEL ALL OVER THE ENGINE WHILE THE UNIT WAS RUNNING. MOTORHOME HAD TO BE TOWED 65 MILES TO BILLINGS, MT CUMMINS REPAI…
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WHILE TRAVELING IN MONTANA IN OUR 2006 MONACO DIPLOMAT MOTORHOME WITH THE CUMMINS ISL400 ENGINE A FUEL LEAK DEVELOPED IN THE ENGINE. THIS LEAK INVOLVED THE LINE FROM THE FUEL PUMP TO THE FUEL RAIL SPRAYING DIESEL FUEL ALL OVER THE ENGINE WHILE THE UNIT WAS RUNNING. MOTORHOME HAD TO BE TOWED 65 MILES TO BILLINGS, MT CUMMINS REPAIR FACILITY. A NEW FUEL LINE WAS INSTALLED, ALONG WITH A BRACKET WHICH IS NOW BEING INSTALLED ON THESE FAULTY LINES DUE TO THESE REPORTED FUEL LEAKS. NUMEROUS MOTORHOME OWNERS WITH THIS ENGINE HAVE REPORTED THIS POTENTIALLY DANGEROUS SITUATION TO BOTH CUMMINS AND VARIOUS COACH MANUFACTURERS. OWNERS ARE OF THE OPINION THAT A RECALL SHOULD BE ISSUED FOR THESE ENGINES DUE TO THE POTENTIAL OF A CATASTROPHIC ENGINE FIRE DUE TO THESE LEAKS. DRIVERS OF THESE UNITS WOULD NOT EVEN BE AWARE OF A FIRE ON THE COACH SINCE THE ENGINE IS AT THE REAR OF THE VEHICLE. *TR
Official recalls
308V070000 · Visibility:windshield Wiper/washer:linkages
Feb 14, 2008
MONACO IS RECALLING 1,733 MY 2006-2007 DIPLOMAT AND HOLIDAY RAMBLER ENDEAVOR MOTOR HOMES EQUIPPED WITH WIPER SYSTEMS SUPPLIED BY AM EQUIPMENT. THE DRIVE MOTOR LINK BECOMES DISENGAGED DURING OPERATION FROM THE WIPER DRIVE ARM WHERE IT ATTACHES TO THE DRIVE ARM CAUSING THE WIPER SYSTEM TO FAIL.
Consequence & remedy
Consequence: WHEN THE WIPER SYSTEM FAILS, THE OPERATOR WILL HAVE REDUCED VISIBILITY WHICH COULD RESULT IN A CRASH.
Remedy: MONACO WILL REPLACE THE COMPLETE UNDER-THE-HOOD WIPER SYSTEM WITH A NEW MODEL, REUSING THE WIPER ARM AND BLADES. THE RECALL BEGAN ON MARCH 11, 2008. OWNERS MAY CONTACT MONACO AT 1-800-685-6545.
07V311000 · Engine And Engine Cooling:engine:diesel
Jul 20, 2007
ON CERTAIN MOTOR HOMES BUILT WITH CUMMINS ISL CM850 DIESEL ENGINES, THE CONNECTING ROD CONTAINS A MACHINING DEFECT IN THE WRIST PIN BUSHING OF THE ROD THAT COULD CAUSE A SEIZURE OF THE PISTON PIN.
Consequence & remedy
Consequence: IF ALLOWED TO PROGRESS, THIS CAN LEAD TO ENGINE FAILURE WITH THE POSSIBILITY OF THE ROD RUPTURING THE LOCK CAVITY, OIL AND DEBRIS ON THE ROADWAY AND VEHICLE CRASH.
Remedy: MONACO IS WORKING WITH CUMMINS TO RECALIBRATE THE ENGINE CONTROL MODULE AND ENHANCE THE ENGINE PROTECTION SYSTEM ENABLING IT TO PROVIDE EARLY DETECTION OF THE FAILURE MODE AND AVOID MORE SERIOUS ENGINE DAMAGE AND RESULTANT SAFETY HAZARD. CUMMINS WILL ALSO INSTALL A NEW VALVE COVER WITH A CRANKCASE PRESSURE SENSOR FREE OF CHARGE (PLEASE SEE 07E033). OWNERS MAY CONTACT CUMMINS AT 800-343-7357 OR MONACO AT 1-800-685-6545.
05V366000 · Exterior Lighting:headlights:switch
Aug 24, 2005
ON CERTAIN MOTOR HOMES, THE HEADLIGHT SWITCH IN THE FRONT ELECTRICAL BOX/FIREWALL CAN OVERLOAD.
Consequence & remedy
Consequence: CHANGES IN THE COMPONENT SUPPLIER RELAY REQUIREMENTS WITH AN UPDATED CONTROLLER WERE CAUSING THE HEADLIGHTS TO STOP FUNCTIONING WITHOUT WARNING. THIS COULD POTENTIALLY CAUSE A CRASH WHILE DRIVING AT NIGHT.
Remedy: DEALERS WILL INSTALL A NEW WIRING HARNESS. THE RECALL BEGAN ON SEPTEMBER 30, 2005. OWNERS MAY CONTACT MONACO AT 1-800-685-6545.
Model-level recall history does not show whether a particular VIN is affected or has received a repair. Check a VIN with NHTSA ↗
NHTSA investigations
0No exact-year investigations in this snapshot.