Which parts fail
Components named in complaints (engine, cooling system, oil leaks, timing chain, exhaust).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2003 Mazda Mazda6 owners, lightly cleaned up (personal details are redacted by NHTSA).
Tl* the contact owns a 2003 Mazda Mazda6. The contact stated that while driving approximately 50 MPH, the vehicle stalled without warning. The contact stated that blue smoke was emitting from the tail pipe as the check engine light illuminated. The vehicle was taken to an independent mechanic for diagnosis. The mechanic stated that the catalytic converters were clogged and would have to be replaced. Additionally, the mechanic stated that the front passenger's side tie rod was loose and could fracture. The vehicle was not repaired. The VIN was not available. The approximate failure mileage was 122,000.
Tl* the contact owns a 2003 Mazda 6. The contact stated while inspecting the vehicle, an unknown fluid started leaking onto the ground. The failure occurred without warning. The vehicle was taken to a dealer, where it was diagnosed that the radiator cap and coolant bypass fitting had malfunctioned. The vehicle was not repaired. The vehicle was taken to an independent mechanic, where it was repaired. The manufacturer was made aware of the issue. The approximate failure mileage was 125,326.
I drive a 2003 Mazda 6s, which I purchased from bigger's Mazda in elgin, il. This vehicle was purchased new from them. My area of concern involves the check engine light on my vehicle, and the performance of the vehicle when this light is on. On April 2, 2004 my check engine light appeared for the third time. When I operate my vehicle with the light on it performs erratically and unusual. The last time the light came on, I was pulling out into traffic, and my vehicle bogged down. In turn, the driver behind almost rear-ended me. While driving my vehicle yesterday, I went to pass a car on the expressway, and again my car bogged down. Every time that I take my car to the dealer, I provide them with the same complaint. I have paperwork to show that I have taken it in three times. After a recent visit to my dealer, they stated, "we have no fix for the check engine light. …
I purchased my 2003 Mazda6 in June of 2003. Since then it has been in the shop for mutiple problems. Several recalls of course, but the first major problem came when the car was about 1 year old and my radiator seam at the bottom seperated. They replaced the radiator. When I picked the car up my air conditioning was not working, so I returned the car and the problem was fixed at that time. April of 2005, my car only had about 19,000 miles on it my air conditioning started blowing hot air. I took it to the dealer and the stated that my freon was low and charged it up. I asked how that could be with a car as new as this one and they stated, it was normal. For a car that is less than 2 years old?? Last week, August of 2005, once again my air is blowing hot,particulaly when sitting in an idle position,works better upon accleration. …
Beginning in 2006, my 2003 Mazda 6 would randomly experience power failure while driving. This was both scary and dangerous. I would be driving, the car would completely loose power with no warning and all the lights on the dashboard would come on. I would have to pull over, turn my car off and back on, and then it would work fine till it randomly happened again. Obviously loosing power at a high speed is extremely dangerous for both myself and the other drivers. I took it to the dealership many times and they were never able to determine a cause. I brought my car to the dealership over 10 times for this behavior. Finally in August 2008, I was reading on a Mazda message board that this behavior is caused by a bad throttle body. There was even a Mazda service bulletin issued for it in 2006 (bulletins 01-016/06 last issued May 18, 2006). …
On 17 feb 2011 I was driving my 2003 Mazda 6s and while driving at a low speed of 25 MPH all my lights on my dashboard turned on and my car immediately began to reduce speed almost to a stand still. Luckily I was able to pull to the side of the road in time to avoid any accidents or possible damage to my vehicle. I restarted my car and was able to proceed in driving. However my engine light remained on. I researched this issue online and found that someone with the same model vehicle and year had the same issue almost verbatim. The referenced a service bulletin from Mazda bulletin no: 01-016/06 released in 2006 regarding throttle body replacement. I read the bulletin and sure enough it stated to inspect the letters on the throttle body. It showed aa,ab,ba markings = no good and bb marking = good. So I inspected my vehicles throttle body letter and sure enough it was "aa". …
Traveling at freeway speeds in ca on the san francisco bay bridge during evening traffic, my 2003 Mazda6 suddenly went into "safe or limp" mode. This caused abrupt loss of power with no ability to accelerate, which almost caused a multi vehicle accident. When taken to a mechanic, the root cause was a code DTC p2135 for a defective throttle body. Mazda admits 3 (three) versions of their throttle body for that vehicle defective with automatic discard if there is a MIL with DTC p2135(per technical service bulletin no. 01-016/06 issued 05/18/2006 by Mazda north American operations), and throttle body markings "aa","ab","ba". Mine is an "aa". Obviously Mazda admits that these are defective, but only replaced them under warranty and my vehicle is not under warranty any longer. They call the new part an "upgraded version". …
Bought a 2003 Mazda 6 last year, my tachometer kept going crazy and the car would die out. I took it to good year, 3 codes came up. They changed the cam shaft sensor and the EGR valve. That didn't fix the problem, good year took the parts out, put mine back in and told me to take it to a Mazda dealership. I took it to Mazda, they told me I had to change my PCM because it was shorting out, and my EGR valve and that should take care of the problem. They quoted me 2K dollars for everything. I asked them how much they were charging for the parts, they told me 1100 for the PCM and 200 for the EGR, the rest was labor. As the service advisor quoted me prices, I told her I can buy a PCM online for 145. She said, yes, you can do that, but we won't warranty the job because it's not our part. I told them are you sure that will take care of the problem? They said yes. I told them okay fine! …
Check engine light came on car was hesitating in middle of highway felt like it wanted to shut off made it home next day car did not start had it towed to the dealer car kept in shop for a month dealer could not figure out the problem said it was a sensor in the engine that was defective got the car back but it since then continued to give me problems brought the car back to original dealer crystal Mazda for 3 recalls in july04 and other problems, in april05 check engine light suddenly turns on in the middle of a busy highway car starts to jerk and just died car was towed to the dealer and they called me weeks later to tell me the engine seazed I have had a lemon law case with kimmel and silverman for a year now dealership have been very nasty to me as well as the manufacturer they do not want to fix the vehicle or give me a replacement I also requested a copy of an invoice describing …
While driving home the car seemed to have lost all power, but was still running. I was able to coast to my house but then tried to stop and the car surged. I had to pull the emergency brake to stop. I was quite shaken at that point. The engine light came on. I was able to drive it back to town to have the car checked, no error codes showed up on the computer. The engine light did go off, the car ran fine for about 3 months then proceeded to do the same thing. The car lost power but I was able to coast to my place of work. However even though there seemed to be no power again when I tried to brake the car surged and the car almost jumped the curb, which would have put me in my office. I again had the vehicle checked, no errors. After researching it seems this May be due to the automatic throttle sensor. …
Engine complaints in other Mazda6 years
Frequently asked questions
How common are engine problems on the 2003 Mazda Mazda6?
NHTSA has 46 complaints about the engine & cooling of the 2003 Mazda Mazda6, 26% of the model year's 174 complaints. The component named most often is engine (10 mentions).
Is there a recall for 2003 Mazda Mazda6 engine problems?
No. NHTSA lists no engine & cooling recall for the 2003 Mazda Mazda6, though it has 6 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2003 Mazda Mazda6 engine problems start?
Half of the complaints with a recorded mileage happened before about 52,000 miles, and 48% before 25,000 miles.
Is it dangerous?
Owners linked 0 crashes, 1 fire and 0 injuries to engine & cooling problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.