2003 Mitsubishi Diamante problems & reliability
56 owner complaints filed with NHTSA for the 2003 Mitsubishi Diamante, alongside 2 safety recall campaigns. Last verified Aug 7, 2026. Complaints are unverified reports submitted by owners to the federal Office of Defects Investigation.
Each complaint is counted once (by NHTSA case number), even when it names several vehicles.
1 complaint report injuries (1 injured).
Federal crash records (FARS 2020–2023): 2003 Mitsubishi Diamante vehicles were involved in 1 fatal crash with 1 occupant death. Involvement counts are not adjusted for how many are on the road and do not imply fault or a vehicle defect.
Most reported problems
| Component | Complaints | Share |
|---|---|---|
| Visibility → | 28 | 50% |
| Engine and Engine Cooling → | 17 | 30% |
| Power Train | 4 | 7% |
| Service Brakes, Hydraulic | 4 | 7% |
| Equipment | 3 | 5% |
| Suspension | 3 | 5% |
| Tires | 3 | 5% |
| Electrical System | 2 | 4% |
| Fuel System, Gasoline | 2 | 4% |
| Air Bags | 1 | 2% |
Component groups as classified by NHTSA. A complaint can name more than one component, so shares may sum to more than 100%.
All 15 reported components →Common symptoms owners describe
Keyword analysis of complaint narratives; one complaint can describe several symptoms.
Mileage when problems occurred
Among the 42 complaints that included a usable odometer reading, the median reported incident mileage was 60,000 miles (middle 50% between 37,860 and 64,750 miles).
Complaints by incident year
What owners report
“Tl* the contact owns a 2003 mitsubishi diamante equipped with cooper cs3 tires (na). While driving 25 mph, air from the vehicle's front driver side tire began to be released. The contact pulled the vehicle into a fuel station/repair shop where the tire was replaced. The contact took the vehicle to the independent…”
Tires · filed Jul 22, 2019
“Tl* the contact owns a 2003 mitsubishi diamante. The contact stated that the heater core fluid leaked onto the central computer and caused the transmission to fail. In addition, the gear shifter could not be released from third gear. The vehicle was not taken to the dealer. The vehicle was not repaired. The…”
Power Train · filed Mar 13, 2013
“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…”
Engine and Engine Cooling · filed Jun 2, 2011
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Technical service bulletins
27 manufacturer communications (TSBs, service campaigns, warranty extensions) are on file with NHTSA for the 2003 Mitsubishi Diamante. The 10 most recent:
This is a Dealer Letter sent to dealers informing that Mitsubishi Technical Training has launched the 3rd quarterly technician quiz for 2023.
DEALER LETTER · Service Bulletin/Repair Instructions · issued Jul 21, 2023
This Technical Service Bulletin provides instructions and material safety data sheets for removal of rap-film adhesive residue.
TSB-23-00-004 · Service Bulletin/Repair Instructions · issued Apr 24, 2023
This Technical Service Bulletin reviews the regulations that require a label showing the reduction in load carrying capacity be affixed to vehicles when the total net weight of accessories is more than 1.5 percent of…
TSB-23-00-001 · Service Bulletin/Repair Instructions · issued Apr 24, 2023
This is a Dealer Letter sent to dealers informing that Mitsubishi Technical Training has launched the 2nd quarterly technician quiz for 2023.
DEALER LETTER · Service Bulletin/Repair Instructions · issued Apr 21, 2023
This Technical Service Bulletin was sent to dealers to explain the difference between normal dew condensation, which is a natural phenomenon, and water penetration caused by improper sealing or a defective/broken part.
TSB-22-54-003 · Service Bulletin/Repair Instructions · issued Apr 7, 2022
This is a service newsletter (Tech Talk) that was sent out to dealers.
TT253 · Service Bulletin/Repair Instructions · issued Nov 26, 2019
This is a Technical Service Bulletin sent to dealers. This bulletin supersedes TSB-18-00-003, issued April, 2018, to add updated information for Carrying Capacity Reduced Label.
TSB-19-00-008 · Service Bulletin/Repair Instructions · issued Jul 30, 2019
This is a message sent to dealers, to inform them that an update for MEDIC will be available.
MEDICUpdate517 · Service Bulletin/Repair Instructions · issued Feb 27, 2018
This is a service newsletter (Tech Talk) that was sent out to dealers.
TT237 · Service Bulletin/Repair Instructions · issued Feb 26, 2018
This is a service newsletter (Tech Talk) that was sent out to dealers.
TT218 · Service Bulletin/Repair Instructions · issued Aug 28, 2015
TSBs are repair guidance manufacturers send to dealers — they are not recalls and repairs are not automatically free. Full documents are available on NHTSA’s site.
Safety recalls
The 2003 Mitsubishi Diamante has 2 NHTSA recall campaigns — recall repairs are free at franchised dealers regardless of the vehicle’s age.
Check whether your specific vehicle is affected
Recall campaigns often cover only certain VIN ranges. Enter your VIN on the official NHTSA site to confirm whether your vehicle is included and whether the repair is still open.
Check VIN on NHTSA →Buying a used 2003 Mitsubishi Diamante?
- · Decode the seller’s VIN with our free VIN decoder to confirm the exact year, engine and trim.
- · Check for unrepaired recalls by VIN on NHTSA’s official lookup — recall repairs are free.
- · Among complaints with usable mileage, the median reported incident mileage was 60,000 miles. This does not predict when a particular vehicle will develop a problem.