My Echo is a 2001 with 15,000 miles. Took it to the dealer for three reasons.
1. The "rear brake tube freezing" problem did not include my Echo since the newer parts that solve the problem were already included during manufacturing. No charge.
2. The door lock pulls were rattling. New ones seem thicker and, so far, no more rattling. No charge.
3. "Check Engine" light came on. I thought it was because of the gas cap not being tight enough but the reason was because of carbon buildup (code 51). Mechanic cleaned top on engine and cleared the codes. Service provider said it was not under warranty so charged $60 labor plus $20 for the cleaner plus tax. Service provider was very nice but told me to use octane 87 and not 89 or 90. Owner's manual reads "select octane rating 87 or higher." I plan to call Toyota customer service about it.
I looked in the $150 service manual I bought and theres no mention of code 51. They list codes in numerical order, but many of them are not in the book. Im assuming that the dealer added a can of injector cleaner? Because the valves were carboned up? Hmmm. Unlikely that higher octane gas caused this problem, if indeed that is the problem. Also unlikely IMHO that "cleaner" is going to fix anything. How is the car used? Mostly short trips?
Most any engine will experience carbon build-up if you run 89+ octane gas in it when it only requires 87. Besides wasting money, that's another reason not to spend for the good stuff if your car doesn't need it.
Receipt says "concern 51" so I mistakenly thought that might be the code number. Service provider suggested using different brand of octane 87 gas and start using fuel injector cleaner every other oil change. I called Toyota Customer Service rep, who said the Customer Relations Manager at the dealer will have all the info shortly and should contact me by Wednesday. Service provider at the dealer did not tell me that there was a CRM there. I am not upset at anyone but just trying to get correct info to prevent future carbon buildup.
The Yahoo Echo group had a mention of a cabin air filter located behind the glove box. I don't remember seeing this in the service book. Before I remove the thing, is it cleanable or just replacable? How often should it be cleaned/replaced?