2004 TOYOTA PRIUS

Typical onset: 100,000-180,000 mi

Symptoms: Triangle of death warning light with multiple DTCs (P0A80, P3006, P3009), Drastically reduced fuel economy (drops from 45+ to 30-35 mpg), Loss of power on acceleration, engine running constantly to compensate, Car may enter limp mode or refuse to start

Fix: Replace the NiMH battery pack—either OEM Toyota ($3,000-3,500 parts alone), refurbished aftermarket ($1,200-1,800), or individual cell replacement if caught early. Labor is 2-3 hours for straightforward swap. Many owners opt for refurb packs with 1-3 year warranties.

Estimated cost: $1,500-4,000

Typical onset: 120,000-200,000 mi

Symptoms: P0A94 or P0A93 codes (DC/DC converter or inverter malfunction), Check engine light with loss of power, No start condition—ready light won't come on, Clicking or buzzing noise from under rear seat area

Fix: The inverter assembly (which includes the DC-DC converter and motor control electronics) is a $2,500-3,500 part from Toyota. Aftermarket refurbs run $800-1,500. Labor is 3-4 hours. Common failure is the capacitors inside; some shops can rebuild for $500-800 if you're patient.

Estimated cost: $1,200-4,200

Typical onset: 80,000-150,000 mi

Symptoms: Speedometer, fuel gauge, or MFD screen goes completely blank, Intermittent gauge flickering or dim display, Odometer reading disappears, Sometimes accompanied by check engine light or TRAC OFF light

Fix: Failed solder joints on the cluster circuit board are the root cause. Replacement cluster from Toyota is $800-1,200, but many specialists rebuild/resolder these for $200-400 with 1-2 week turnaround. Labor to remove and reinstall is 1 hour. Can be DIY-friendly if you're comfortable shipping it out.

Estimated cost: $250-1,400

Typical onset: 150,000-220,000 mi

Symptoms: White smoke from exhaust on cold starts, Coolant loss with no visible leaks, Milky oil on dipstick or oil cap, P0301-P0304 misfire codes, rough idle

Fix: The 1NZ-FXE can blow head gaskets, often between cylinders 2 and 3. Head gasket replacement is 8-10 hours labor, plus machine shop work (deck and valve job). If the engine has been overheated, expect piston ring damage too. At this mileage, many shops recommend a used JDM engine swap (4-6 hours labor) instead.

Estimated cost: $1,800-3,500

Typical onset: 120,000-180,000 mi

Symptoms: Burning 1 quart every 500-1,000 miles, Blue smoke on deceleration or hard acceleration, Low oil warning light between 5,000-mile oil changes, Fouled spark plugs (oil-soaked)

Fix: Piston ring wear is the culprit—common on 1NZ engines. Fix requires engine-out rebuild (pistons, rings, hone, seals)—16-20 hours labor total. Most owners choose to live with it and check oil every fill-up, or swap in a low-mileage used engine for $1,500-2,500 installed.

Estimated cost: $2,500-4,500

Symptoms: Sudden loss of power steering assist (steering becomes very heavy), EPS warning light on dash, Codes C1231, C1252, or C1391, May occur intermittently at first, then permanent

Fix: The EPS control module or motor fails. Toyota had a recall (05V133000) for this but many cars aged out before symptoms appeared. EPS motor assembly is $600-1,000 used, $1,500-2,000 new. Labor is 2-3 hours. Some units can be sent out for ECU repair ($300-500).

Estimated cost: $800-2,500

Typical onset: 100,000-160,000 mi

Symptoms: Brake warning light and ABS light on simultaneously, Hard brake pedal with little to no braking power, Loud motor/pump noise from ABS unit under hood, Codes C1256, C1391, or C1252

Fix: The regenerative brake system's hydraulic accumulator loses pressure. The entire ABS actuator assembly must be replaced—it's not serviceable. OEM part is $1,800-2,500, aftermarket reman $800-1,500. Labor is 3-4 hours including brake bleed and system test.

Estimated cost: $1,200-3,200