2005 Toyota Prius brakes problems

Total or near-total loss of braking response at various speeds. Pedal goes to floor with minimal or no deceleration. Some cases required stomping on pedal hard to engage rear brakes only, or impact with another vehicle to stop.

When: Varied: during normal driving, at traffic lights, highway speeds, downhill sections. Some cases specific to wet/rainy conditions or shortly after vehicle restart.

Symptoms owners cite: Pedal goes to floor with no or minimal braking response; Gradual loss of braking pressure requiring heavy pedal pressure; Loss of power assist; brakes work only after hard stomp; Brake and ABS warning lights illuminate; High-pitched alarm or buzzer sounds; Red brake light on dashboard; Problem often resolves after turning engine off and back on

Codes mentioned: C1247, C1357, C1300, C2300, C1256, C1391, CM1300

Repairs/costs cited: Dealers performed: linear solenoid valve reinitialization, skid control ECU replacement (~$1800–$2500), brake stroke sensor replacement, computer assembly replacement (part 89540-47130, ~$2250), brake actuator/accumulator replacement (~$2500). Some resets of electronic control modules (ECM/ECU).

Recalls/TSBs owners mention: Toyota replaced skid control ECU; some cases covered under hidden/extended warranty (expired Dec 2017 for some components). Some owners reported Toyota initially denied problem or said vehicle was performing to specification. Service bulletins exist for brake actuator assembly (TSB codes C1256, C1391) with warranty coverage that expired.

Brakes temporarily lose effectiveness when car hits a bump, pothole, railroad tracks, metal plate, or speed bump—particularly while braking. Car lurches or surges forward for 1–2 seconds, or braking feels delayed. Often accompanied by traction control / skid warning light.

When: Occurs when braking while crossing uneven pavement, potholes, speed bumps, railroad tracks, or metal plates. Frequency varies; some owners report it occurs 40% of the time at certain speeds, others report it becomes rare after learning to avoid those situations.

Symptoms owners cite: Car lurches or surges forward momentarily while braking; Brake pedal feels unresponsive for 1–2 seconds after hitting bump; Loss of braking power described as 'brake fade'; Traction control / skid warning light illuminates; ABS light may illuminate; Feeling of loss of control; Problem more pronounced at higher speeds (30–50 mph)

Codes mentioned: C1247

Repairs/costs cited: Brake stroke sensor replacement resolved problem in one case. In other cases, dealers found no mechanical fault and performed computer resets or linear solenoid calibration. Some cases had no diagnostic codes present.

Recalls/TSBs owners mention: Dealers often dismissed complaints or claimed behavior was 'normal for a hybrid' or 'how the car is designed.' Some references to ABS system functioning as designed. One TSB mentioned for brake actuator (expired warranty Dec 2017).

Brakes apply in a sudden, jerky manner approaching a stop, or feel grabby and difficult to modulate smoothly. Feels like alternating over-braking and under-braking, especially at low speeds or when coming to final stop.

When: Observed at any speed but especially noticeable at slow speeds (traffic lights, reversing). More frequent on wet roads or in early morning with condensation/dew. Intermittent initially, gradually increasing in frequency.

Symptoms owners cite: Jerky brake operation despite constant pedal pressure; Alternating over-braking / under-braking sensation; Brake feels 'grabby' in wet conditions; Difficulty modulating brake pedal smoothly; Car jolts forward when brakes grab; Noise from engine compartment when pressing brake hard; Problem worse in rain or wet conditions; improves after ~15 minutes of driving

Repairs/costs cited: Brake stroke sensor replacement fixed problem in one documented case. Rear brake drums cleaned, turned, and adjusted in another case without resolving issue. Dealers initially found no stored error codes in some cases.

Recalls/TSBs owners mention: Dealers often performed drum brake service or claimed problem was normal hybrid behavior. One case notes TSB for brake actuator with expired warranty. Generally dismissed or attributed to normal operation.

Anti-skid / traction control system cuts engine power or braking power in response to perceived wheel slip, even on dry roads or in situations where such intervention is unsafe (e.g., merging into traffic, steep snowy hills, acceleration around curves). System responds too aggressively to normal road imperfections or wet conditions.

When: When accelerating away from stop on wet/rainy day, on snowy hills, on gravel, over railroad tracks, painted road stripes, or wet surfaces. Also during sharp turns at higher speeds or over bumps/potholes during acceleration.

Symptoms owners cite: Sudden engine power loss lasting 0.5–2 seconds; Brakes cut power, causing car to feel like it accelerates forward during braking attempt; Traction control / skid control light flashes; Repeated cutting in and out of power, causing lurching; On snowy hills: car stops attempting to move forward and slides backward; System activates on dry roads from painted stripes, railroad tracks, even slight moisture; Makes acceleration into traffic risky or impossible

Repairs/costs cited: No repairs documented. Owners managed by changing driving habits or avoiding certain maneuvers (e.g., avoiding aggressive acceleration, not driving in snow).

Recalls/TSBs owners mention: Dealers stated behavior was 'normal for the Prius' and 'how the car is designed.' No fix offered or acknowledged as a defect. One owner noted Toyota refused to acknowledge design flaw even when owner pointed out vehicle was dangerous as designed.

Skid control electronic control unit (ECU) fails, causing sudden brake system malfunction, warning lights, and loss of braking ability. Computer controls all major braking functions (conventional brake, regenerative brake, ABS, VSC) and sensor coordination.

When: Can occur suddenly while driving at highway speeds or normal speeds. One case at 35 mph, another at 65 mph highway speed.

Symptoms owners cite: High-pitch buzzer / alarm sounds; Red brake warning light and ABS light illuminate; Brake pedal becomes stiff; difficult to depress; Loss of braking power or very long braking distances; Problem resolves temporarily after turning engine off and restarting; Problem recurs during same or subsequent drives

Codes mentioned: C1300, CM1300

Repairs/costs cited: Skid control ECU replacement required (~$2000–$2500). Part number cited: 89540-47130. 4–5 hours labor; part must be ordered overnight or longer.

Recalls/TSBs owners mention: Toyota has recalled this part on 2002–2003 Sequoia vehicles but does not consider it a defect on Prius. Dealers sometimes say they 'haven't seen this before.' No recall or warranty help offered to Prius owners out of warranty.

Brake actuator or fluid accumulator assembly fails, causing loss of brake assist, brake locking, or complete loss of braking. This is a known issue with extended warranty (TSB) that expired December 31, 2017. Part is critical to hybrid regenerative brake integration.

When: Can occur at any mileage. Cases documented from 45,000 miles to 130,000 miles. One owner reports two actuator failures on two different Prius vehicles.

Symptoms owners cite: ABS and brake warning lights come on; Brakes become stiff and unresponsive; Complete loss of braking power possible; Pedal to floor with no response; Squeaky noise under hood that persists; Problem may recur after attempted repair

Codes mentioned: C1256, C1391

Repairs/costs cited: Brake actuator and fluid accumulator replacement. Cost: ~$2500. One owner reports repair was covered under 'hidden warranty' that required fighting for, then failed again after 1 year. Another case shows dealer refused second replacement because owner was ~1 month out of warranty on new part.

Recalls/TSBs owners mention: Toyota issued extended warranty / technical service bulletin (TSB) for brake actuator assembly, but this expired December 31, 2017. Owners contacting Toyota reported no compassion and 'good luck' response when warranty expired. One service manager reported this is a known, recurring issue seen 'over and over again' at dealership; Toyota did a full redesign of braking system on 2017 model year.

Brake failures or erratic behavior correlate with hybrid battery charge state (especially when battery is full from regenerative braking on highway), regenerative brake system engagement, or transition between electric and gasoline engine operation.

When: One case: brake failure occurred when hybrid battery was nearly full after highway deceleration and regenerative braking. Car lurches forward at idle when engine transitions from electric to gas. Another case: brakes work differently depending on battery charge and system mode.

Symptoms owners cite: Brake failure when regenerative braking system cannot assist (battery full); Car surges forward at stops when engine shifts from electric to gas; Low hybrid battery reported by dealer; brakes may not work when battery is low (battery powers some brake assist functions)

Repairs/costs cited: Dealers noted low hybrid battery but reported no brake system mechanical fault. One case: dealer said 'brakes do not work when battery is low and battery is charged by braking,' suggesting brake function depends on battery state.

Recalls/TSBs owners mention: Dealers attributed behavior to normal hybrid system operation. No repairs offered in some cases. One dealer mentioned 'hybrid battery seemed low' but found charging system okay.

Floor mat becomes unhooked from restraints and wedges between brake and accelerator pedals, reducing sensitivity of both pedals and requiring hard pressure to engage brakes or accelerator.

When: While driving at highway speeds (60–70 mph).

Symptoms owners cite: Loss of sensitivity on both brake and gas pedals; Must press very hard to get reaction from either pedal; Unable to maintain normal speed; Problem persists for several minutes before owner can safely pull over; Problem recurs periodically

Repairs/costs cited: Owners manually resecured floor mat to hooks. Problem recurred multiple times, suggesting hooks are weak.

Recalls/TSBs owners mention: None documented. Owner suggests Toyota install locking hooks instead of current ones that easily twist and unhook.