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2003 Mitsubishi Diamante

Owner reports · Recalls · Investigations

Similar to other model years

Owner complaints for the 2003 Mitsubishi Diamante do not stand out strongly from the model-year median of 31.5.

About this comparison →

How this year compares

Owner complaints by model year

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Counts vary with age, sales and reporting. They are not failure rates.

What owners reported most

All reported categories

Tap a category to read its complaints. One report may name several components.

When problems were reported

Mileage at the reported incident

44 reports with mileage · 12 unknown

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.

  • Visibility. Review the 28 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
  • Engine And Engine Cooling. Review the 17 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
  • Power Train. Review the 4 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →

NHTSA owner reports · September 18, 2026 snapshot.

1 crash reports0 fire reports1 injury reports

Engine And Engine Cooling complaints

17 reports
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71,677 miles · Jun 2, 2011
Engine And Engine Cooling

I HAVE A 2003 MITSUBISHI DIAMANTE LS WITH 71677 MILES ON IT ALL OF THE SUDDEN MY HUSBAND (THE PRIMARY DRIVER) TELLS ME THAT EVERY TIME HE GETS OUT OF THE CAR HE FEELS LIGHT HEADED AND NAUSEOUS. DAYS LATER THE FRONT WINDSHIELD STARTED FOGGING UP WHILE DRIVING AND AFTER TURNING THE CAR OFF (WHETHER IT IS WARM OR COLD OUTSIDE) I G…

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I HAVE A 2003 MITSUBISHI DIAMANTE LS WITH 71677 MILES ON IT ALL OF THE SUDDEN MY HUSBAND (THE PRIMARY DRIVER) TELLS ME THAT EVERY TIME HE GETS OUT OF THE CAR HE FEELS LIGHT HEADED AND NAUSEOUS. DAYS LATER THE FRONT WINDSHIELD STARTED FOGGING UP WHILE DRIVING AND AFTER TURNING THE CAR OFF (WHETHER IT IS WARM OR COLD OUTSIDE) I GOOGLED WHY WOULD THIS HAPPEN AND HAVE SPOKEN WITH A FEW MECHANICS AND THEY ARE TELLING ME THAT IT IS THE HEATER CORE GOING OUT, AND THAT THE REASON WHY MY HUSBAND IS GETTING LIGHT HEADED AND NAUSEOUS IS BECAUSE THERE IS ANTI-FREEZE COMING INTO THE INTERIOR OF THE CAR WHICH IS VERY DETRIMENTAL TO YOUR HEALTH. I HAVE READ A TON OF COMPLAINTS ON DIFFERENT WEBSITES AND THEY ALL SAY THE SAME THING. I CONTACTED MITSUBISHI CORPORATE TODAY AND SPOKE WITH A [XXX] IN CUSTOMER SERVICE AND EXPLAINED TO HER WHAT WAS GOING ON AND ASKED WHY MITSUBISHI HAS NOT DONE ANYTHING ABOUT THIS. FIRST BECAUSE OF THE HEALTH IMPLICATIONS, SECONDLY BECAUSE OF THE SAFETY ISSUE OF THE WINDSHIELD FOGGING UP WHILE YOU'RE DRIVING TO WHERE YOU CAN'T SEE AND THIRDLY THAT FROM READING THE COMPLAINTS, THE HEATER CORE IS RIGHT ABOVE THE COMPUTER IN THE CAR SO IF THE HEATER CORE IS LEAKING ANTIFREEZE, IT COULD FRY THE COMPUTER AND CAUSE A POSSIBLE CRASH IF THE CAR WERE TO STOP SUDDENLY. SHE SAID THAT "SEEING THAT I HADN'T HAD THE CAR INTO A DEALERSHIP IN THE LAST YEAR THAT THERE IS NOTHING THEY CAN DO ABOUT IT". I TOLD HER THAT IT JUST STARTED AND WHAT WAS I SUPPOSE TO DO, LOOK INTO MY CRYSTAL BALL AND KNOW A YEAR AHEAD OF TIME THAT THE HEATER CORE WAS GOING TO GO OUT. THIS IS LUDICROUS! ! ! MITSUBISHI KNOWS THAT THIS IS A SERIOUS ISSUE AND ARE NOT DOING ONE THING TO FIX IT (BY ISSUING A RECALL) WHERE DO WE DIAMANTE OWNERS GO TO GET SOME HELP? DO WE NEED TO FILE A CLASS ACTION LAWSUIT AS THAT SEEMS LIKE THE ONLY WAY A FIRE IS GOING TO GET LIT UNDER THEM (CORPORATIONS TEND TO ACT IF IT MEANS LOSING TONS OF MONEY) THE CAR CAN'T BE DRIVEN AND I'M STILL PAYING ON IT. HELP! INFORMATION REDACTED PURSUANT TO THE FREEDO

NHTSA ODI #10404130

60,000 miles · May 20, 2010
Engine And Engine Cooling

TL* THE CONTACT OWNS A 2003 MITSUBISHI DIAMANTE. THE CONTACT STATED HE NOTICED AN UNUSUAL ODOR OF COOLANT AND THE NEUTRAL INDICATOR BEGAN SPORADICALLY ILLUMINATING. UPON FURTHER INSPECTION, THE CONTACT FOUND COOLANT LEAKING ONTO THE FLOORBOARD. IN ADDITION, THE VEHICLE WOULD INTERMITTENTLY FAIL TO START. THE DEALER PERFORMED A …

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TL* THE CONTACT OWNS A 2003 MITSUBISHI DIAMANTE. THE CONTACT STATED HE NOTICED AN UNUSUAL ODOR OF COOLANT AND THE NEUTRAL INDICATOR BEGAN SPORADICALLY ILLUMINATING. UPON FURTHER INSPECTION, THE CONTACT FOUND COOLANT LEAKING ONTO THE FLOORBOARD. IN ADDITION, THE VEHICLE WOULD INTERMITTENTLY FAIL TO START. THE DEALER PERFORMED A DIAGNOSTIC TEST AND DETERMINED THE FAILURE WAS CAUSED BY THE A.T. CONTROL RELAY AND PRODUCED CODE P1751. THE VEHICLE WAS NOT REPAIRED AND THE VIN WAS NOT AVAILABLE. THE FAILURE AND CURRENT MILEAGES WERE APPROXIMATELY 60,000. UPDATED 10/27/10. *LJ

NHTSA ODI #10331379

60,000 miles · May 20, 2010
Engine And Engine Cooling

TL- THE CONTACT OWNS A 2003 MITSUBISHI DIAMANTE. THE CONTACT STATED THAT THE NEUTRAL LIGHT ON THE VEHICLE STARTED FLASHING ON AND OFF AND HE NOTICED A SMELL OF COOLANT. HE NOTICED THAT THE COOLANT WAS LEAKING ONTO THE FLOORBOARD OF THE VEHICLE. THE FAILURE PROGRESSES UNTIL THE VEHICLE WILL NOT START. THE VEHICLE WAS TAKEN TO…

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TL- THE CONTACT OWNS A 2003 MITSUBISHI DIAMANTE. THE CONTACT STATED THAT THE NEUTRAL LIGHT ON THE VEHICLE STARTED FLASHING ON AND OFF AND HE NOTICED A SMELL OF COOLANT. HE NOTICED THAT THE COOLANT WAS LEAKING ONTO THE FLOORBOARD OF THE VEHICLE. THE FAILURE PROGRESSES UNTIL THE VEHICLE WILL NOT START. THE VEHICLE WAS TAKEN TO A DEALER AND THE OWNER WAS ADVISED THE FAILURE WAS THE A.T. CONTROL RELAY. CODE P-1751. THE FAILURE HAS NOT BEEN REPAIRED. THE CURRENT AND FAILURE MILEAGE IS APPROXIMATELY 60,000. RD

NHTSA ODI #10331374

62,000 miles · Mar 11, 2010
Engine And Engine CoolingVisibility

I HAVE A 2003 MITSUBISHI DIAMANTE WITH 60,000 PLUS MILES. FOR THE PAST SEVERAL MONTHS I HAVE NOTICED A STRONG SMELL OF ANTI-FREEZE COMING FROM THE VENTS AND THE WINDOWS CONSTANTLY FOGGING UP, SOMETIMES TO THE POINT THAT I CANNOT SEE TO DRIVE. I HAVE READ MANY SIMILAR COMPLAINTS AND AGREE WITH OTHERS THAT MITSUBISHI NEEDS TO ISS…

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I HAVE A 2003 MITSUBISHI DIAMANTE WITH 60,000 PLUS MILES. FOR THE PAST SEVERAL MONTHS I HAVE NOTICED A STRONG SMELL OF ANTI-FREEZE COMING FROM THE VENTS AND THE WINDOWS CONSTANTLY FOGGING UP, SOMETIMES TO THE POINT THAT I CANNOT SEE TO DRIVE. I HAVE READ MANY SIMILAR COMPLAINTS AND AGREE WITH OTHERS THAT MITSUBISHI NEEDS TO ISSUE A RECALL FOR THE HEATER CORE, AS I AM SURE THIS IS THE PROBLEM. I HAVE YET TO TAKE MINE IN TO GET IT REPAIRED, SO I DON'T HAVE A COST QUOTE AT THIS TIME. *TR

NHTSA ODI #10318872

60,000 miles · Feb 16, 2010
Engine And Engine CoolingVisibility

ANTI-FREEZE LEAK ON CARPET PASSENGER SIDE NEAR FIREWALL FOGGED UP WINDOWS CHECK ENGINE LIGHT COMES ON AND OFF DUE TO THE LEAK THE ECU STARTED WORKING AWFUL. *TR

NHTSA ODI #10311071

50,000 miles · Jul 9, 2009
Engine And Engine CoolingFuel System, Gasoline

I PURCHASED A USED 2003 MITSUBISHI DIAMANTE FROM BANKSTON DODGE IN 2007. IT WAS CLEAN AND RAN WELL. THERE WAS AN UNUSUAL ODOR INSIDE, BUT SMELLED AS IF IT COULD HAVE BEEN WHAT THE DEALERSHIP USED TO CLEAN THE INSIDE. IT TURNED OUT TO BE ANTI-FREEZE. THE VEHICLE HAD A HEATER CORE LEAK PRIOR TO OUR PURCHASE. RECENTLY THE GAS …

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I PURCHASED A USED 2003 MITSUBISHI DIAMANTE FROM BANKSTON DODGE IN 2007. IT WAS CLEAN AND RAN WELL. THERE WAS AN UNUSUAL ODOR INSIDE, BUT SMELLED AS IF IT COULD HAVE BEEN WHAT THE DEALERSHIP USED TO CLEAN THE INSIDE. IT TURNED OUT TO BE ANTI-FREEZE. THE VEHICLE HAD A HEATER CORE LEAK PRIOR TO OUR PURCHASE. RECENTLY THE GAS GAUGE HAS STOPPED WORKING. *TR

NHTSA ODI #10276190

60,000 miles · Sep 3, 2008
Engine And Engine CoolingPower Train

I OWN A 2003 MITSUBISHI DIAMANTE, AROUND 60K MILES I STARTED NOTICING A SWEET SMELL FROM THE VENTS AND A CONSTANT FOG WHEN THE HEAT OR AIR WAS TURNED ON IN THE CAR. AFTER TAKING MY CAR TO THE MECHANIC I WAS TOLD THAT MY HEATER CORE WAS BUSTED. MY CAR ALSO SDRIVING IN "SAFE MODE" MEANING I CAN ONLY RUN IN SECOND GEAR WHICH IS BUR…

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I OWN A 2003 MITSUBISHI DIAMANTE, AROUND 60K MILES I STARTED NOTICING A SWEET SMELL FROM THE VENTS AND A CONSTANT FOG WHEN THE HEAT OR AIR WAS TURNED ON IN THE CAR. AFTER TAKING MY CAR TO THE MECHANIC I WAS TOLD THAT MY HEATER CORE WAS BUSTED. MY CAR ALSO SDRIVING IN "SAFE MODE" MEANING I CAN ONLY RUN IN SECOND GEAR WHICH IS BURNING A TANK OF GAS EVERY THREE DAY, I LOVE 10 MILES FROM WORK. MY CAR FLASHED IN NEUTRAL WILL IN DRIVE. AFTER RESEARCHING MY PROBLEMS I'VE NOTICE WELL OVER 1000 POSTED VIA INTERNET FROM OTHER MITSUBISHI DIAMANTE OWNERS HAVING THE SAME ISSUE. ITS HARD TO BELIEVE THIS VEHICLE HAS NOT BE RECALLED. THERE ARE GREAT RISKS OF INHALING ANTI FREEZE WHICH IS SEEPING INTO THE CAR THROUGH THE FLOOR BOARDS AND VENTS. I HAVE AN ASTHMATIC CHILD WHO HAS BEEN DRIVING IN THE CAR UNTIL THE PROBLEM WAS BROUGHT TO MY ATTENTION. THIS LEAK MAY ALSO MAKE THE COMPUTER SYSTEM IN THE VEHICLE GO OUT. SOMETHING NEEDS TO BE DONE BEFORE AN ACCIDENT IS CAUSED OR A LIFE IS TAKEN. *TR

NHTSA ODI #10240783

114,132 miles · May 1, 2008
Engine And Engine CoolingPower Train

MY TRANSMISSION RELAY WENT OUT DUE TO A LEAK HEATER CORE. THE CORE HAS BEEN LEAKING FOR SOME TIME AND HAS FOGGED MY WINDOWS SO BAD I COULD NOT SEE AT TIMES, HAVING TO PULL OVER AND WIPE OFF THE FILM. THIS IS A SERIOUS PROBLEM WITH THESE CARS. *TR

NHTSA ODI #10226354

78,000 miles · Apr 16, 2008
Engine And Engine CoolingPower Train

I OWN A 2003 DIAMANTE MITSUBISHI. THE PROBLEM STARTED WITH A CHECK ENGINE LIGHT COMING ON, FOGGING THE WINDOW WITH A FOWL TOXIC SMELL THEN THE CAR WOULD NOT HARDLY MOVE OUT GEAR. I WAS TOLD THAT THE CAR'S HEATER CORE LEAKED ONTO THE COMPUTER WHICH CAUSED THE TRANSMISSION RELAY TO SHORT OUT DO TO THE COMPUTER FAILING. THE COMPUT…

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I OWN A 2003 DIAMANTE MITSUBISHI. THE PROBLEM STARTED WITH A CHECK ENGINE LIGHT COMING ON, FOGGING THE WINDOW WITH A FOWL TOXIC SMELL THEN THE CAR WOULD NOT HARDLY MOVE OUT GEAR. I WAS TOLD THAT THE CAR'S HEATER CORE LEAKED ONTO THE COMPUTER WHICH CAUSED THE TRANSMISSION RELAY TO SHORT OUT DO TO THE COMPUTER FAILING. THE COMPUTER WAS STILL UNDER WARRANTY AT 78,000 MILES BUT I STILL HAD TO PAY FOR THE NEW COMPUTER SYSTEM BECAUSE I WAS TOLD THAT IT WAS THE HEATER CORE THAT CAUSED THE COMPUTER TO FAIL. THIS IS SUCH A POOR DESIGN! THE COMPUTER SHOULD HAVE BEEN PROTECTED IN SUCH A CASE...FUNNY THING IT IS NOW THAT I HAVE HAD TO REPLACE A HEATER CORE, A COMPUTER AND A TRANSMISSION RELAY AT A CUT WRENCHING COST OF $3,675.58. I WROTE A LETTER TO THE PRESIDENT OF NORTH AMERICA MITSUBISHI THAT THE HEATER CORE SHOULD BE A RECALL BUT TO NO AVAIL. I HAVE ALL MAINTENANCE RECORDS ON THE DIAMANTE SO THAT WAS NOT WHAT CAUSED THIS HEATER FAILURE. I DO HAVE THE COMPUTER THAT WAS REPLACED. IT IS NOW APRIL AND THE CHECK ENGINE LIGHT HAS COME BACK ON...NOW WHAT? AJ *TR

NHTSA ODI #10224750

20 miles · Apr 7, 2008
Engine And Engine CoolingVisibility

I HAVE 2003 MITSUBISHI DIAMANTE. MY "CHECK ENGINE" LIGHT CAME ON, SO I TOOK IT IN FOR SERVICE, AND MY HEATER CORE WAS LEAKING ON MY COMPUTER...NOW IT'S GOING TO COST ME AROUND 3,500 DOLLARS....THIS IS A VERY FLAWED DESIGN. THERE SHOULD BE A RECALL ON THIS ITEM. *TR

NHTSA ODI #10223524

Official recalls

2

04V428000 · Equipment:other:labels

Sep 1, 2004

CERTAIN PASSENGER VEHICLES FAIL TO CONFORM TO THE REQUIREMENTS OF FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 208, 'OCCUPANT CRASH PROTECTION.' THE BILINGUAL ENGLISH/SPANISH REMOVABLE AIR BAG WARNING LABELS AFFIXED TO THE DASH AND TO THE SUNVISOR DO NOT MEET THE SIZE REQUIREMENTS OF THE STANDARD.

Consequence & remedy

Consequence: THIS DOES NOT MEET THE REQUIREMENTS OF THE STANDARD.

Remedy: MITSUBISHI CARIBBEAN WILL MAIL A CUSTOMER NOTIFICATION LETTER CONTAINING A WRITTEN DESCRIPTION AND A GRAPHIC OF THE BI-LINGUAL DASHBOARD AIR BAG WARNING LABEL. IN ADDITION, ALL CURRENT 2000-2004 NATIVA OWNERS WILL ALSO RECEIVE REPLACEMENT AIR BAG ALERT LABELS FOR THE SUN VISORS. THIS RECALL IS EXPECTED TO BEGIN DURING MARCH OR APRIL 2005. THE NOTIFICATION TO THE NATIVA OWNERS IS EXPECTED TO BEGIN DURING APRIL OR MAY 2005. OWNERS SHOULD CONTACT MITSUBISHI CARIBBEAN AT 1-787-251-8715.

04V067000 · Equipment:other:owners/service/other Manual

Feb 11, 2004

CERTAIN SPORT UTILITY AND PASSENGER VEHICLES FAIL TO COMPLY WITH FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 225, "CHILD RESTRAINT ANCHORAGE SYSTEMS." THE OWNER'S MANUAL DOES NOT CONTAIN A STEP-BY-STEP DESCRIPTION FOR HEADREST ADJUSTMENT WHEN INSTALLING A CHILD RESTRAINT SYSTEM (CRS) TETHER STRAP.

Consequence & remedy

Consequence: IF THE TETHER STRAP IS IMPROPERLY INSTALLED TO THE TETHER ANCHOR, THE CHILD SAFETY SEAT MAY NOT BE SUFFICIENT RESTRAINED. IN THE EVENT OF A CRASH, THE CHILD COULD BE INJURED.

Remedy: A LETTER OUTLINING THE PROBLEM WILL BE SENT TO OWNERS ALONG WITH A STICKER CONTAINING THE CORRECT INSTRUCTIONS AS WELL AS INSTRUCTIONS ON WHERE TO AFFIX THE STICKER IN THE OWNER'S MANUAL. THE RECALL BEGAN ON MARCH 29, 2004. OWNERS SHOULD CONTACT MITSUBISHI AT 1-888-648-7820.

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

0

No exact-year investigations in this snapshot.