On higher mileage vehicles, an engine misfire may develop and/or the Check Engine Light may illuminate due to a failed ignition coil. It is not uncommon to replace all the coils when the first one fails in order to prevent return trips to the repair shop.
Toyota Avalon Problem Reports
Most Reported Toyota Avalon Problem Reports
The Check Engine Light may illuminate because a component of the oxygen sensor stops working. As a result the engine computer is unable to determine the proper ratio of air to fuel for the engine. Replacing the failed oxygen sensor should correct this concern.
The Evaporative system may have problems with the vapor canister releasing charcoal pellets that plug the vent valve. Typically a Code P0441, P0442 and P0446 will be set. The key code is the P0446 which is a vent valve electrical failure. The proper repair is to replace the entire canister with all the valves as a unit. This is located on top of the fuel tank and is expensive. Our Technicians tell us that for awhile Toyota was covering these problems, but this may have changed. It would not hurt to call the dealer if this problem occurs to see if Toyota is still helping with these repairs.
Debris can get into the idle air control valve. This will restrict the air flow into the engine, causing idle speed and/or stalling when cold. The valve can be cleaned or replaced to correct this concern.
The EGR System tends to get restricted or blocked with carbon after 100,000- 125,000 miles which will cause an emissions test failure for NOX. If the EGR system is equipped with an EGR temperature sensor it will trigger a Check Engine Light for improper EGR flow. The repair is to clean out the EGR passages and the EGR Temperature sensor. Our technicians tell this repair is pretty straight forward and takes about 1-1.5 hours. It is also wise to verify the EGR system components i.e. the Transducer, EGR Valve and VSV Solenoid at this time.
Sludge can build up in the engine because Toyota did not recommend frequent enough oil changes. Lexus will sometimes offer a discount on cleaning the engine if necessary. Owners who changed their oil every 3,000 miles did not experience these problems. This sludge build up can lead to excessive oil consumption.
At higher mileages, (125,000-150,000) the automatic transmission may not shift correctly. This can be caused by the throttle position sensor being out of adjustment or a shift solenoid needing to be replaced. Typically the transmission does not need to be completely overhauled.
If the engine will not crank over, the most common problem is the starter. These will tend to go out at about 100,00-125,000 miles. Sometimes it is only the starter solenoid, but often the complete starter (including solenoid) needs to be replaced.
At higher mileages, an anti-lock brake system wheel speed sensor may wear out and illuminate the ABS warning light. It is recommended to replace the sensor with a factory part and be sure to clean all rust and debris from the mounting area because the mounting distance is critical. Failure to do so may result in the new sensor setting false trouble codes. Be sure to check the condition and runout of the front wheel bearings on the 2WD and 4WD vehicles and the CV joints on the 4WD vehicles since worn wheel bearings and/or CV joints can cause the ABS trigger rings to rub against the ABS sensors and damage them.
The rear Oxygen sensors are a critical element in fuel control (unlike other vehicles) and can cause an emissions test failure for high CO and HCs. The sensing element cracks and and reports an erroneous steady state lean condition which confuses the computer, which in turn makes the fuel mixture overly rich.
well her we are 3 times the charm,. I OWN ONLY TOYOTAS AND THEY HAVE BEEN GREAT WITH THE EXCEPTION OF THE MONEY PIT 2007 AVALON. This all started in 2008, 1 year after its birth, a coil went bad,$400 repair. lets go and move to 2011 more coils fail and it also costs about $300,now we move to 3 years to the date and 5 of 6 cylinders need replacing at the tune of $800.Question why hasn't Toyota admitted to wrong doing and recalled these sh!t car...