OBSOLETE NOTICE February 13, 2026: This bulletin is now obsolete. Please see T-SB-0009-26.
full bulletin at NHTSA ↗2014 Toyota Prius engine problems
severe Owners of the 2014 Toyota Prius have filed 13 NHTSA complaints about the engine at roughly $3,100 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See engine across all vehicles →
Complaints
13
Recalls
0
Avg fix
$3,100
| Model year | engine complaints |
|---|---|
| 2010 Prius | 115 |
| 2011 Prius | 26 |
| 2012 Prius | 44 |
| 2013 Prius | 15 |
| 2014 Prius (this page) | 13 |
| 2016 Prius | 6 |
| 2017 Prius | 8 |
| 2018 Prius | 3 |
1crash
1injury
When does it fail?
Of the 13 engine complaints filed for the 2014 Toyota Prius, here's the actual mileage breakdown — failures cluster heaviest at 125,000-150,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
No new NHTSA engine complaint has been filed on this vehicle in over 6 years — the issue may be aging out of the active population.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering engine on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
This bulletin includes basic procedures for performing a rescue charge on Ni-MH high voltage (HV) batteries. This bulletin should be used in conjunction with the applicable model and model year Repair Manual while performing a rescue charge. The GRX-5100 should be used wherever the Repair Manual references the Toyota Hybrid System (THS) charger.
full bulletin at NHTSA ↗This is to advise of various price adjustments that will affect Toyota Genuine Motor Oil and Long Life Coolant, effective March 1, 2024. These products are ordered through the Toyota Complete Maintenance Care (TCMC) website.
full bulletin at NHTSA ↗TT: HVAC drain tube is found to be blocked/clogged.
full bulletin at NHTSA ↗TSB: OBSOLETE NOTICE August 13, 2020: This bulletin is no longer applicable and is now obsolete.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners describe the 2014 Prius losing power mid-drive: stalling at highway speed, dropping power on hills, and shutting down during normal operation. Some failures recur even after the EOE-PRIUS recall refresh. One owner's vehicle stalled on the freeway with no throttle response — a terrifying loss of control in traffic. Another reported the hybrid system shutting down entirely.
Engine control module failure, inverter/motor-generator ECU reset, and unexplained power loss are the most serious complaints. Dealers often cannot duplicate the stall conditions, leaving vehicles unrepaired and owners uncertain. One owner noted that their dealer had confirmed some vehicles still experienced inverter failure *after* the recall was performed.
Head gasket failures also appear frequently. One owner reported severe knocking ("death knock") caused by poor intake manifold and EGR design, allowing coolant into the combustion chamber — no warning lights came on. Another confirmed coolant mixing with ignition vapors via chemical test.
Oil issues round out the concerns: owners report cracking in the oil tank (multiple dealers called it a "well-known" manufacturing defect), excessive oil consumption, and burning oil internally so quickly the reservoir empties in weeks. One owner gets anxiety every time the maintenance light comes on because of the tank crack risk.
Rough starts, misfires, and power drops on inclines complete the pattern. These are serious durability and safety problems affecting hybrid and combustion system reliability.
Same Toyota Prius engine reports on nearby years: 2011 · 2012 · 2013
Failure modes owners describe
Engine Control Module (ECM) Failure
Engine control module failed, causing complete engine stall at highway speed with loss of throttle response. Dashboard warning lights and beeps preceded the failure.
When: Highway speeds; specific mileage not stated
Symptoms owners cite: engine stall; yellow warning triangles on dashboard; beeping warnings; throttle unresponsive
Repairs/costs cited: Engine control module replacement required; dealer claimed part was unavailable and had to be shipped from Toyota
Recalls/TSBs owners mention: Dealer indicated this was a rare occurrence
Inverter/Motor-Generator ECU Reset
Motor/generator ECU reset causing hybrid system shutdown and vehicle stop while driving. Occurred even after EOE-PRIUS recall software refresh was performed.
When: After EOE-PRIUS recall in Feb 2014; no specific mileage reported
Symptoms owners cite: hybrid system shut down; vehicle stops while driving; loss of power
Repairs/costs cited: EOE-PRIUS recall performed on 2/14/14 at San Francisco Toyota with 15-year unlimited mileage warranty, but failures persisted in some vehicles
Recalls/TSBs owners mention: EOE-PRIUS recall (software refresh in inverter); 15-year unlimited mileage warranty extension
Oil Tank Crack
Crack in oil tank forming during manufacturing due to oil residue preventing proper clamping of two tank pieces. Crack widens over time, leading to oil leaks.
When: Variable; worsens if oil changes are delayed
Symptoms owners cite: oil leaks; maintenance light activation
Repairs/costs cited: Multiple Toyota dealers (Berkeley, Vallejo, Daly City) identified this as a well-known manufacturing defect; owners advised regular oil changes mitigate the issue
Power Loss on Hills
Vehicle loses power climbing hills, engine weakens progressively, and car rolls backward. Occurred twice; resulted in one accident when vehicle could not climb a small hill in San Francisco.
When: Hill driving; specific mileage not stated
Symptoms owners cite: progressively weakening power; noise from car; inability to climb hills; vehicle rolling backward; reduced acceleration with load
Cylinder Head Gasket Failure
Cylinder head gasket failure attributed to poor design of intake manifold and EGR system. Coolant entered combustion chamber causing severe knocking ('death knock'). Updated parts available but no recall issued.
When: During highway trip; occurred without warning lights
Symptoms owners cite: severe engine knocking; death knock sound; misfiring on cylinders 2 and 4; no warning lights
Repairs/costs cited: Updated parts available to address the design flaw; risk of bent connecting rods from coolant ingression
Recalls/TSBs owners mention: No recall issued despite known design issue
Engine Stall - Unexplained
Engine stalled at low speed (40 mph) without warning. Vehicle could not be restarted at roadside. Failure could not be duplicated by dealer; no repair performed.
When: 40 mph; 63,000 miles
Symptoms owners cite: sudden engine stall; no warning lights
Repairs/costs cited: Not repaired; failure could not be duplicated
Recalls/TSBs owners mention: Manufacturer provided case number
Loss of Motive Power
Vehicle lost all motive power while driving; warning light illuminated before failure. Failure could not be diagnosed or repaired by dealer. Failure recurred.
When: Approximately 73,211 miles
Symptoms owners cite: loss of motive power; warning light illumination
Repairs/costs cited: Dealer did not diagnose or repair; no parts replaced
Engine Stall with Self-Recovery
Engine stalled without warning at 35 mph but restarted after a few attempts. Failure self-corrected. Dealer found no faults on complete diagnostics; owner planned inverter replacement.
When: 35 mph; approximately 49,000 miles
Symptoms owners cite: sudden engine stall without warning; successful restart after multiple attempts
Repairs/costs cited: No faults found on complete dealer diagnostics; owner decided to replace inverter
Head Gasket Failure with Internal Coolant Mixing
Head gasket failure allowing ignition vapors to enter engine coolant. No warning lights despite failure. Confirmed by chemical testing.
When: Unknown mileage; vehicle well-maintained
Symptoms owners cite: misfiring on cylinders 2 and 4; severe engine knocking; no check engine light or warning; ignition vapors in coolant
Repairs/costs cited: Failure confirmed by chemical test; available for inspection
Power Loss at Highway Speed
Vehicle lost power at 70 mph, dropping to 55 mph for short duration before power returned. Occurred on hot day.
When: Highway speed (70 mph); no specific mileage reported; on hot day
Symptoms owners cite: sudden power loss; speed drop from 70 to 55 mph; temporary loss of power recovery
Oil Consumption and Overheating
Vehicle consuming oil excessively and overheating. Attempted repairs unsuccessful; root cause not resolved.
When: Unspecified mileage
Symptoms owners cite: excessive oil consumption; engine overheating
Repairs/costs cited: Repair attempts made but unsuccessful
Internal Oil Burning
Engine burning oil internally at a severe rate, consuming full oil supply within 4 weeks.
When: Unspecified mileage
Symptoms owners cite: rapid internal oil burning; oil depletion in 4 weeks
Misfire with Rough Starts
Misfire code present along with rough cold starts and issues under light load.
When: Unspecified mileage
Symptoms owners cite: misfire code; rough starts; light load hesitation
Repairs/costs cited: Technical service bulletin TSB-0116-15 referenced
Recalls/TSBs owners mention: Technical service bulletin TSB-0116-15 available
Synthesized from 13 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 2 most recent
Car is burning oil internally. Oil is burning up in 4 week s tume
misfire code along with rough starts/light load. T-SB-0116-15
Had engine trouble with your 2014 Toyota Prius?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the engine problem on the 2014 Toyota Prius?
It's a meaningful issue. 13 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $3,100.
At what mileage does the engine typically fail?
Based on the 13 complaints filed, engine issues most often appear around 63,296 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2014/Toyota/Prius.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.