really awful
Crashes / Fires:
1 / 0
Injuries / Deaths:
0 / 0
Average Mileage:
104,692 miles

About These NHTSA Complaints:

This data is from the NHTSA — the US gov't agency tasked with vehicle safety. Complaints are spread across multiple & redundant categories, & are not organized by problem.

So how do you find out what problems are occurring? For this NHTSA complaint data, the only way is to read through the comments below. Any duplicates or errors? It's not us.

2003 Toyota Sienna engine problems

engine problem

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2003 Toyota Sienna Owner Comments

problem #4

Mar 152010

Sienna 6-cyl

  • Automatic transmission
  • 43,000 miles


Here is a list of mechanical malfunctions indicating manufacturing defects on my Toyota Sienna. The current models recalled by Toyota motors do not cover all vehicles with defects. Based on my personal experience in the past few years, Toyota motors have a lot of lying employees in their authorized dealership. In short, Toyota motors put their business interest way ahead of the life safety of american people. I hope National Highway Traffic Safety Administration will check this manner and enforce proper regulation. Updated 03/14/10 the consumer stated the engine would stall. The dealer replaced the upper radiator hose and coolant. The consumer also stated he had problems stopping the vehicle, which led to an accident. Updated IVOQ 10/12/10

- Temple City, CA, USA

problem #3

Jul 202009


  • 125,769 miles
2003 Toyota Sienna, spontaneous, uncontrolled acceleration. First occurrence on or about 7/20/09. At least 3 successive occurrences. Toyota dealer (larry H miller big Toyota city) was able to duplicate problem in road tests. When it happened to me, I threw transmission in neutral. Engine hit redline in time it took to turn key to off.(1-2 seconds) first mis identified as sticking throttle cables. Toyota replaced cables eventually (after recurrence) replaced throttle body. Wife nearly had accident with first occurrence, had to stand on brakes to get car stopped. Shut down vehicle in left turn lane on busy six lane road. Vehicle towed. I had to replace brakes/rotors. Able to avoid accident with recurrence by showing wife how to throw transmission in neutral and shut down vehicle. Wife does not trust vehicle although new throttle body seems to have solved problem. Toyota kept vehicle twice for total of two weeks, we paid over $1,300. Toyota never acknowledged nor accepted responsibility for this serious safety issue. Offered free car wash when we complained to service manager.

- Sandy, UT, USA

problem #2

Jun 242009


  • 160,000 miles
When picking up my vehicle from Toyota town in stockton, ca, we discovered that the oil light was on following a 60,000 mile service. The mechanic released the vehicle to us without explanation. Then after two visits in the same day to the service department, my husband demanded an explanation. The mechanic said it was our problem that there was sludge or "gel" in the oil that was released when he removed the head for servicing. After changing the oil himself twice, my husband saw the oil light go off. Thinking that it was safe to drive, we took it on the highway the next day. Within 100 miles the engine froze, leaving us stranded on a major interstate. Currently, the dealer is refusing to fix the problem even though Toyota recently settled this problem with the owners of the 2002 models. Our van is a 2003. This problem obviously continues to exist.

- Stockton, CA, USA

problem #1

Jun 012007


  • Automatic transmission
  • 90,000 miles
Our 2003 Sienna van (Toyota) has begun throwing blue smoke out the exhaust. We took it to a mechanic that told us that it's a valve, ring sludge problem in the motor. He said it's been happening to this particular model. I researched it on google and found this website from other owners of Siennas. From what I understand Toyota has not been willing to fix this problem and has in fact found a "loophole"through an acknowledgement of the problem. So, here I am with my complaint. Hope that you can help us out as I do not have the funds to buy a new engine. Thank you.

- Astoria, OR, USA

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