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 2004 Toyota Sienna owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact's mother owns a 2004 Toyota Sienna. While the contact's mother was driving at an undisclosed speed, several unknown warning lights illuminated. The contact stated that the warning lights illuminated on and off for days and months. The vehicle was taken to an independent mechanic where DTC: P2241 was retrieved. The vehicle was not repaired. The contact was advised to take the vehicle to the dealer. The vehicle was taken to the dealer where the failure code was confirmed. The contact was informed that the oxygen sensors needed to be replaced. In addition, the contact was informed that a TSB for the ECM software update needed to be performed. The contact stated that the vehicle was not repaired because the ECM software update was performed, and the ECM software update damaged the ECM. The manufacturer was made aware of the failure and a case was filed. …
The outside temperature was below 32 and it was close to 25 or so. When I was driving the car at 40 MPH with engine temp still slightly above cold(not at optimal which is almost half way) and slowed down by using gentle brakes(not hard brakes). Just before the vehicle comes to a full stop, there is unintended acceleration and I could see even the RPM(scale) to spike temporarily. This has been happening every time when outside temp is cold and vehicle is driven with cold or slightly above cold engine temperature. There is a risk of hitting another vehicle or meeting accident if misjudge my braking because of this problem.. Please note : this problem disappears when engine temperate is at optimal and I have driving a Honda accord 2008 exl for last 7 years(was bought new one), I never had experienced this problem in that car even when driven with cold engine.
When negotiating moving into traffic at slow speeds, when a small amount of accelerator movement is made the vehicle rapidly accelerates making it necessary to quickly apply the brakes to avoid collision. The vehicle was purchased used from a dealer and there was a recall bulletin (tech service bulletin issued 11/7/2003 for 04-05 Sienna bulletin no tc007-03 out on the engine control module. When pointed out to the dealer they simply stated that that recall was only available to the original purchaser and then only if reported within the first three months after purchase. Was told by two dealers that the recall did not apply to our vehicle and later that a recall was not issued for that problem. ( I have a copy of the origional recall notice stating the above problem)
Tl* the contact owns a 2004 Toyota Sienna. While driving approximately 55 MPH, the contact heard a loud noise and lost steering control. The vehicle was pulled over to the side of the road and towed to the contact's residence. The vehicle was later taken to an independent mechanic where it was diagnosed that the crankshaft pulley failed and needed to be replaced. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure. The failure mileage was 96,321.
The vehicle overheated and caused the engine to seize while driving 45 MPH. Consumer and his children were left strained for several hours before help arrived. Vehicle was towed to the dealer, who d replaced the radiator, which was covered under a recall. Consumer stated he was never notified of this recall.
Radiator ruptured and the engine overheated; hose replaced in steering column recall; rust protective tape recall; dvd screen replaced and the entire dvd player replaced(screen still not easily visible in middle row); passenger seat belt replaced; middle passenger seat belt failing; gasoline smell inside of car with ac on recirculation; driver's window fell inside door in snow storm and was not considered a safety issue to get a loaner vehicle even though the vehicle could not be locked; tires completely bald and leaking under 30,000 miles, dvd player must be at a high db volume and when returned to radio/cd will almost deafen you; interior lights have to be manually over ridden or will drain battery; car hesitates 1-2 seconds when trying to quickly accelerate and then lurches forward alarmingly; cruise control is not functioning; waiting to have fuel mixture sensor replaced. …
Check engine light came on in 2004 Sienna le, called dealership for appt, the next day, the air conditioning went out. I live in phoenix, az, where it is routinely 115 in the summer. Took car van to dealership where price to fix is $4200. Compressor exploded and sent shards of metal throughout entire A/C system. Toyota is aware of this problem, as posted in their TSB ac003-05, but refuses to cover their defect under a recall as it's not life-threatening. Let me tell you, riding in a car for any length of time in 115 degree weather is life-threatening. A/C is not a luxury in az; it is necessary for survival. Upon contacting Toyota customer service, they deny any culpability; however, there are plenty of forums, including toyotanation.com, in which people have routinely had this problem with this vehicle. …
I have 2 different complaints. Driver side seat heater burned legs of 3 different drivers before complete failure. Heat was not adjustable. Driver and passenger heaters stopped working at same time. Took to dealer, recommended new heating element ($1000+). Opted not to fix. 2nd complaint, check engine, vsc, and trac off lights illuminated. The van has been sent to the dealer on at least 3 occasions. Gas cap has been replaced several times, spark plugs changed. Will go off for brief periods, but always to return. This has been going on for at least 30,000 miles. I could live with the check engine light on, but if the other lights are illuminated, that indicates these components are not working-kind of important-skid control & traction control!! …
I was driving my van when I noticed the A/C was not blowing cold air, it was more cool than cold. Then it would blow hot air on occasion then it would eventually blow cold air again. Eventually the air wasnt cold at all and it would constantly blow hot air. This was very unconfortable due to the fact that it was summer and I live in florida. I took it to a mechanic and he told me it was the compressor, so I had it replaced. The ac was blowing cold again, this lasted for about 12 months. The same issue started to happen again. First cool air then on and off hot air and now nothing but hot air. I took it back to my mechanic and he told me it might be the relays, I replaced both of the relays and the air is still not cold. I then found out that it was the compressor again. I cannot afford to replace the compressor and im afraid to replace it if the problem will just continue. …
Radiator failure resulting in coolant leakage in the transmission fluid and transmission is failing. I noticed my 2004 Toyota Sienna had some belt noise that got worse. The van was due for a water pump/timing belt change. Later the engine temperature gauge read high and after checking the fluids noticed the antifreeze level to be low and topped it up. A week later while driving on the highway steam started coming out of the hood. I noticed the pink fluid had also leaked out of a tube (looked like a relief tube) on the driver side. Radiator level was low. The transmission fuel looked pinkish and read about six inches above the max level on the dipstick. Trans fluid was milky pink, thick, and had grainy deposit. Took the van to the autoland dealer in springfield, nj to diagnose the problem and to have the water pump and timing belt change at the same time. Had to leave the van overnight. …
Related recalls
Engine and engine cooling
Toyota is recalling certain model year 2004 avalon vehicles; 2004 and 2005 camry, camry solara, highlander, and sienna vehicles, 2006 highlander hybrid; 2004 and 2005 Lexus es330 and rx330; and 2006 Lexus rx400h vehicles manufactured from June 1, 2004 through March 31, 2005, equipped with the 1mz-fe or 3mz-fe engine.
Remedy: Toyota will notify owners, and dealers will check the crankshaft pulley to identify whether it was produced by the U.S. Supplier. If so, the dealer will replace the pulley with a new one at no charge.
Engine complaints in other Sienna years
Frequently asked questions
How common are engine problems on the 2004 Toyota Sienna?
NHTSA has 58 complaints about the engine & cooling of the 2004 Toyota Sienna, 3% of the model year's 2,062 complaints. The component named most often is engine (11 mentions).
Is there a recall for 2004 Toyota Sienna engine problems?
Yes — NHTSA recall 11V-539 (engine and engine cooling, Nov 9, 2011). Recall repairs are free at authorized dealers.
At what mileage do 2004 Toyota Sienna engine problems start?
Half of the complaints with a recorded mileage happened before about 70,000 miles, and 35% before 25,000 miles.
Is it dangerous?
Owners linked 1 crash, 0 fires 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.