2005 Toyota Prius engine problems

The engine shuts down completely while driving, sometimes accompanied by multiple warning lights (red triangle, check engine, VSC, brake, hybrid system). Vehicle enters fail-safe mode and can limp on electric motor only, or may not restart immediately.

When: Occurs at various speeds (5 mph to 80 mph), some linked to low fuel warnings or fuel bladder collapse; early 2005 models (Jan-Sept 2005)

Symptoms owners cite: Sudden complete loss of engine power while driving; All or multiple dashboard warning lights illuminate simultaneously; Vehicle becomes unresponsive to throttle and gear shift; Vehicle continues coasting as if in neutral; Check engine light turns on; Red triangle warning light; Vehicle stability control warning light; Brake warning light; Hybrid system warning light; Difficulty restarting; sometimes requires waiting or multiple restart attempts; May run fine after restart

Codes mentioned: ECM (Electronic Control Module) program logic error, TSB relating to navigation system

Repairs/costs cited: Toyota ECM reprogramming performed by dealers at no charge under recall PE05029; some owners report software updates were not applied at initial service; some dealers claim failure to find any fault on diagnostic

Recalls/TSBs owners mention: Special Service Campaign PE05029 for 2004 and early 2005 model year Prius; Toyota to reprogram ECM at no charge; vehicle will enter fail-safe mode allowing limited electric-motor operation; brake and steering remain functional; owner to restart engine via start button once vehicle stopped

Fuel bladder collapses over the fuel sending module, causing the vehicle's computer to incorrectly register an empty tank and shut down the gasoline engine while fuel actually remains in the tank.

When: When fuel tank becomes low (around 1-2 gallons remaining, high ambient temperatures noted in some cases)

Symptoms owners cite: Low-fuel warning light illuminates while fuel gauge shows 1-2 bars remaining; Engine shuts down abruptly at highway speeds despite fuel present; Dashboard warning lights illuminate (check engine, red triangle, consumption indicator); Vehicle only runs on battery/electric motor at reduced speed; High ambient temperature (examples: 90°F, 91°F) noted in complaints

Codes mentioned: Computer registers 'out of fuel' error

Repairs/costs cited: Dealer recommended refueling before fuel level becomes too low as temporary workaround; fuel bladder condition detected by observation; actual fuel added to tank sometimes would only partially fill tank on first attempts

Recalls/TSBs owners mention: Toyota investigating the problem; dealer suggested keeping fuel tank level higher as remedy; no formal recall action documented in narratives

The water pump that circulates coolant through the inverter system fails, causing loss of engine power, multiple warning lights, and potential catastrophic overheating. Pump failure can blow fuses controlling other systems.

When: At various mileages ranging from 8,300 to 223,000 miles; one failure at approximately 41,000 miles; some failures late in vehicle ownership

Symptoms owners cite: Sudden loss of acceleration ability; Multiple warning lights illuminate; Check engine light comes on; Vehicle speed control loses power; Burning electrical smell from under hood; Transmission may become stuck in park; Front wheels lock up and will not roll; Vehicle cannot be restarted after shutoff; Fuse blowage affecting multiple systems

Codes mentioned: P0A93 (Inverter Cooling System Performance), Code 34352 with sub-code 346

Repairs/costs cited: Inverter water pump replacement; TSB EG001-07 applies; repair cost approximately $500 including labor and parts; replaced pump may have been on critical back order (noted Sept 2010 delivery); one owner paid $422.32 for three-way coolant control valve failure

Recalls/TSBs owners mention: Toyota aware of issue; covered under warranty in some cases; TSB EG001-07 issued for replacement; one owner reported free replacement under warranty at dealer; some cases outside warranty period and owner charged full repair cost

Spark plugs fail prematurely and ignition coils short out, causing rough running and carbon deposits in the engine. Requires replacement of multiple spark plugs, ignition coils, and engine carbon cleaning.

When: At low-to-moderate mileage (7,100 to 78,646 miles); occurred even on regularly serviced vehicles

Symptoms owners cite: Engine bucking and shaking while driving; Check engine light illuminates; Reduced acceleration ability; Violent shaking at low speeds (described as unbalanced washer shaking); Carbon buildup on engine detected

Codes mentioned: Misfire code (cylinder-specific, e.g., #1 cylinder misfire reported)

Repairs/costs cited: Replacement of spark plugs (at least 2); replacement of ignition coils (at least 2); engine carbon cleaning required; total repair cost cited as $989.81; one dealer offered partial refund of $348.10 after customer complaint; one spark plug (#1) replacement cost not separately stated

Recalls/TSBs owners mention: Toyota offered partial reimbursement ($348.10) on one repair; no broad recall noted; one dealer warned owner not to wash engine or warranty would be voided

Engine consumes oil internally at an abnormal rate despite no visible leaks. Vehicle requires oil top-ups between scheduled maintenance intervals, eventually requiring $3,500+ engine rebuild at high mileage.

When: By 100,000 miles (customer checked at 99,400 miles during service); oil alarms triggered at 103,000 miles and beyond

Symptoms owners cite: No oil on dipstick at 100,000-mile service; Oil level warning alarms sound at 103,000 miles; No visible oil leaks anywhere on vehicle; Continued oil consumption requiring frequent top-ups

Repairs/costs cited: Owner adding 2 quarts at 103,000 miles; owner carries oil in car and checks at every fuel stop; service shop suggested $3,500+ engine rebuild as remedy; owner chose interim workaround of regular top-ups instead

Recalls/TSBs owners mention: Toyota aware of issue but will not acknowledge to owners; information provided to service centers but not communicated to customers; no recall or warranty extension documented

The three-way coolant control valve becomes stuck, preventing normal coolant circulation and causing overheating. When valve fails completely, coolant lines rupture, creating smoke and risk of fire.

When: While driving on highway; one incident at 65 mph

Symptoms owners cite: Check engine light illuminates; Large amount of smoke from engine; Burned plastic smell; Coolant line rupture; Steam from engine area; Potential fire risk

Repairs/costs cited: Three-way coolant control valve replacement; repair cost $422.32; one complaint references valve sticking and preventing coolant flow

Recalls/TSBs owners mention: Toyota aware of widespread problem with valve sticking; no formal recall noted in narratives; customer had to pay out of pocket for repair

The inverter unit fails, disabling hybrid system operation. Vehicle may lose power, refuse to restart, or exhibit electrical malfunctions including dashboard light failures and HVAC issues.

When: Occurs at various mileages and driving conditions

Symptoms owners cite: Loss of power while driving; Multiple warning lights illuminate; Vehicle will not restart or restarts intermittently; Dashboard lights become inoperative; Speedometer and gear indicator inoperable; HVAC system blows alternating hot and cold air; Wipers may malfunction

Repairs/costs cited: Inverter replacement required; one dealership replaced entire inverter unit; repair cost not always specified; circuit board inspection suggested as preliminary step

Recalls/TSBs owners mention: Dealership repairs covered or denied based on warranty status; no standard recall documented

When a front wheel slips in icy/slippery conditions, traction control cuts power to both wheels, stopping motor operation for approximately 1 second. If wheels continue slipping, this cycle repeats, causing vehicle to stall on slippery inclines and preventing forward momentum recovery.

When: In slippery road conditions (rain, ice, snow); on hills

Symptoms owners cite: Motor shuts down when front wheel slips; Both wheels stop rotating momentarily; Substantial loss of forward momentum; Repeated stall cycles on slippery terrain; Vehicle unable to climb slippery hills; Motor starting and stopping as power switches between wheels

Repairs/costs cited: No repair documented; owner requested reprogramming of traction control to allow reduced power rather than zero power to slipping wheel

Recalls/TSBs owners mention: Dealer claimed no knowledge of design flaw; no software update or recall offered

Dashboard lights fail to illuminate or operate, making vehicle operation unsafe. Vehicle may not shut off when power button is pressed, draining battery.

When: At higher mileage (255,000 miles noted); can occur after power cycling attempts

Symptoms owners cite: Dashboard lights do not illuminate on startup; No way to determine if vehicle is on/off or in proper gear; Vehicle will not shut off when power button pressed; Vehicle continues to operate without dashboard indication

Repairs/costs cited: No repair details provided; owner sought assistance from dealership sales manager after hours

Recalls/TSBs owners mention: Dealership acknowledged safety concern that vehicle cannot be confirmed as on or off without dashboard lights

Vehicle caught fire while parked in driveway with engine off. Fire started in rear driver-side area, destroying cargo compartment, tire, and rear interior components.

When: While parked; after returning from work; at 19,300 miles; external temperature moderate (70-75°F)

Symptoms owners cite: Smoke visible inside vehicle within minutes of parking; Flames visible from underneath vehicle; Electrical burning smell prior to fire (in related inverter pump failure cases)

Repairs/costs cited: Vehicle total loss; destroyed in fire

Recalls/TSBs owners mention: No recall or investigation documented in narrative; vehicle was not modified as plug-in hybrid