2006 Toyota Avalon powertrain problems

The electronic 5-speed automatic transmission hesitates or fails to engage promptly when the driver accelerates from a stop or at speeds below 10–20 mph. The engine revs (sometimes to 3,000–7,000 rpm) before the transmission selects a gear, causing a delayed response or violent lurch forward. Owners report this occurs especially after slowing or braking, then attempting to accelerate; it happens during turns, merging, and low-speed city driving. Dealers and Toyota representatives attribute this to normal operation of the drive-by-wire system or claim the transmission is 'learning' the driver's style, but the problem persists across multiple vehicles.

When: Typically within the first few weeks to months of ownership; can occur throughout vehicle life. Some owners report daily occurrences; failure mileage cited in one complaint: 155,835 miles.

Symptoms owners cite: Engine RPM surge without proportional acceleration; Delayed or absent downshift when accelerator depressed; Transmission feels as if it is in neutral before engaging; Violent lurch or jerk forward when transmission finally engages; Hesitation when accelerating from complete stop; Uneven or erratic shifting at 5–35 mph; Transmission hunting for correct gear; Shuddering on inclines

Codes mentioned: Check Engine Light (intermittent illumination noted in some cases)

Repairs/costs cited: One owner reported successful recalibration of the Engine Control Module/ECM (operation code EG7023) with marginal improvement. Another owner noted reprogramming of transmission computer or replacement with a 'faster' chip was suggested but not performed. One complaint mentions electronic transmission software needed replacement, but manufacturer stated no aftermarket software was available. No universal fix documented across complaints.

Recalls/TSBs owners mention: Toyota representatives and dealers consistently state this is normal operation of the drive-by-wire electronic transmission system or that the computer is learning the driver's style. One owner received a minor transmission shift-point adjustment. Another owner threatened NHTSA complaint and was offered ECM recalibration. No TSB or formal recall documented in these narratives for transmission hesitation.

The engine accelerates suddenly and violently without driver input or beyond the driver's intended throttle position, occurring both at low speeds in parking situations and at highway speeds. In one critical case, after a Toyota service visit for an oil line recall, the vehicle accelerated violently into a fence and curb. In another, a vehicle accelerated into a concrete wall at a car wash, totaling the car; airbags did not deploy. Owners report the vehicle will accelerate by itself even when the accelerator is released, and braking has little or no effect during these episodes.

When: Instances range from early ownership to later miles (155,835 miles reported in one total-loss incident). One incident occurred immediately (15 minutes) after dealer service.

Symptoms owners cite: Vehicle accelerates violently without driver pressing accelerator; Vehicle accelerates while accelerator is released; Brake pedal has no effect or minimal effect in stopping the surge; Acceleration occurs in parking lots, at stop lights, and during low-speed maneuvers; Vehicle surges forward unexpectedly during normal driving; Abnormal squealing or mechanical noise heard during acceleration events

Repairs/costs cited: One owner reported dealer inspection found 'mechanical fault' but did not identify or repair the cause. Vehicle continued to fail after inspection. Another vehicle was deemed a total loss and destroyed. No repair records provided in narratives.

Recalls/TSBs owners mention: Toyota inspected one vehicle post-incident and concluded it 'checks out fine' and blamed the driver and floor mats. Another owner was told nothing was wrong after dealer examination. One owner received an email response stating 'We are not aware of any similar incidents.' No recalls or TSBs for unintended acceleration documented in these narratives.

The transmission appears to slip out of gear or fail to transfer engine power to the wheels at low speeds, particularly when slowing to a near-stop and then attempting to accelerate. The engine revs but the vehicle does not move, or moves only after a significant delay. Owners describe the sensation as the car being in neutral momentarily. This creates dangerous gaps in traffic flow and has nearly caused rear-end collisions.

When: Recurring throughout ownership, often daily or multiple times per week. Reported as early as first week of ownership.

Symptoms owners cite: Transmission slips—appears to be in neutral; No power transfer to wheels when accelerator pressed; Engine revs but vehicle does not move or moves only after delay; Problem occurs during slow turns, stop-and-go traffic, and after braking; Unpredictable nature—may occur 60% of the time in one owner's estimate

Repairs/costs cited: Dealers unable to replicate problem during service visits in most cases. One complaint mentions shift-point adjustment made by dealer. No successful repair documented.

Recalls/TSBs owners mention: Dealers consistently state the vehicle is operating normally and unable to duplicate the issue. No TSBs or recalls for transmission slip documented in these narratives.

The electronic throttle (drive-by-wire) system exhibits inconsistent response to accelerator pedal input. Some owners describe a lag or dead zone where pedal input produces no engine response until the pedal is depressed beyond 50% travel; then the system responds abruptly or excessively. Other owners experience sudden, disproportionate acceleration to light pedal inputs. One owner noted that the accelerator has become insensitive, requiring pedal movements to have almost no effect after ten months of ownership.

When: Reported from early ownership onward; one owner noted the problem present for ten months without improvement.

Symptoms owners cite: Delayed or absent throttle response until pedal is depressed beyond 50%; Sudden or excessive power delivery after initial lag; Over-sensitive accelerator response to minor pedal inputs; Inconsistent day-to-day throttle behavior; Check Engine Light flashing on and off during power delivery events; Very little throttle response on rare occasions

Codes mentioned: Check Engine Light (intermittent flashing)

Repairs/costs cited: One owner reports the problem worsened after ten months of ownership and had the vehicle towed for dealer service. No repair outcomes documented.

Recalls/TSBs owners mention: Toyota representatives explained that the drive-by-wire system is functioning as designed—the pedal sends a signal to an electronic control module that determines throttle position, not a mechanical rod. Hesitation is described as the system determining how much to accelerate. No repairs or TSBs documented.

The ignition key can be removed from the switch even when the transmission is not in Park, allowing the vehicle to roll freely if parked on an incline. One owner's vehicle began rolling while she was exiting the car on a slight incline after the key was removed. The problem is reported across multiple model years (1997, 1998, 2006) but Toyota has refused to address it in warranty or otherwise.

When: Ongoing; one incident reported after key removal on an incline. Owner received car in September 2014 and experienced the problem.

Symptoms owners cite: Key can be removed from ignition without transmission in Park; Vehicle rolls freely on incline after key removal

Repairs/costs cited: Owner was told the 36,000-mile warranty does not cover this repair.

Recalls/TSBs owners mention: Toyota initially did not believe the report. Later response stated the issue is outside warranty coverage. No fix or TSB documented.

The engine oil line ruptured without warning, causing rapid and complete oil loss from the engine. The owner heard noise when the transmission shifted and discovered the oil level empty the next day upon inspection. Upon adding oil, it leaked immediately. The cause was determined to be a broken oil line. No warning systems (Check Engine Light or other alerts) functioned to alert the driver before failure.

When: Occurred during normal highway driving after vacation; discovered the day after the incident.

Repairs/costs cited: Engine damage likely; vehicle towed to independent repair shop.

Recalls/TSBs owners mention: No manufacturer response documented in this narrative. This complaint references an oil line recall but does not specify manufacturer follow-up.

Engine stalls while driving, particularly during turns or gear changes at moderate speeds (20 mph). The vehicle experiences a hard stall with loss of motive power. After dealer repairs for the stalling issue, the vehicle returned to normal operation but the stalling recurred.

When: Failure mileage: 27,000 miles.

Symptoms owners cite: Engine stalls while turning; Engine stalls during gear changes at ~20 mph; Slow throttle response when pressing accelerator pedal; Recurrent stalling after repair attempts

Repairs/costs cited: Dealer diagnosed ignition coil damage and power steering flush requirement. Vehicle was repaired but stalling recurred.

Recalls/TSBs owners mention: Not documented in this narrative.