Owners of 2016 Prius models describe a consistent pattern of electrical and software instability. The most troubling failures involve brake system warnings—"braking power low," ABS, pre-collision system, and lane-departure alerts—that appear intermittently with stored fault codes (C1403, C1407, C1415, C1A45, C1A50, P157800) but cannot be replicated or fixed by dealers. One owner reported nearly losing brake authority during an actual drive cycle after warnings appeared.
Navigation and infotainment systems fail frequently: radio and nav power-cycle in critical driving situations (rain, dark, unfamiliar roads), rendering them unreliable when most needed. GPS location data shows errors of 11+ miles from actual position, creating emergency response risk with onboard SOS systems. The instrument cluster goes completely black in some cases, leaving drivers unable to see speed.
Rodent-attracted wiring—attributed to soy-based insulation coating—causes brake line, fuel line, and sensor harness damage exceeding $2,700 in repair costs. Toyota denies warranty coverage and refuses to redesign the wiring, despite acknowledging this is a known issue. One owner drove with only one functional brake line before warning lights appeared.
Battery and hybrid system failures include unexplained drain, overheating (at 7,000 miles), and power loss while driving. A 2016 Prius Four built in early 2016 cannot toggle metric/English units despite factory claims, violating Canadian safety regulations with no fix offered except a costly trade-in.
One unintended acceleration event during parking resulted in a total-loss crash.
Failure modes owners describe
Instrument cluster / dashboard display malfunction
Electronic dashboard goes blank, speedometer display fails to show speed, or entire instrument panel loses display. Occurs intermittently and may resolve after vehicle shutdown and restart.
When: Intermittently during operation; one case at 70 miles driven; varies with mileage
Symptoms owners cite: Completely black instrument cluster with no speed information; Inability to see speedometer while driving; Instrument panel goes blank while radio/nav system malfunctions
Navigation / infotainment system failures
Radio and navigation system repeatedly power on and off, especially during critical driving situations (night, rain, unfamiliar areas). Navigation system reboots continuously in early ownership, rendering the system unreliable. GPS location reports inaccurate position (off by 11 miles in one case).
When: First six months of ownership in one case; September onward in another; intermittent throughout ownership
Symptoms owners cite: Radio/navigation turns off and on continuously; Navigation system constant rebooting; Instrument panel goes blank when nav/radio fails; GPS reports incorrect vehicle location; System unavailable when needed for navigation
Repairs/costs cited: One owner reported dealership stated a software update 'might' fix it but was not yet available
Recalls/TSBs owners mention: No solution provided; update status unknown
Bluetooth / phone connectivity dropout
Bluetooth connection to phone drops 7–10 seconds after initial pairing. Display console resets as if vehicle just started when phone connects, even while stationary.
When: Intermittent, occurs immediately upon phone connection
Symptoms owners cite: Bluetooth drops after 7–10 seconds of connection; Display console resets when phone connects; Audio player can connect separately
Metric/English unit display toggle failure
Speedometer and associated systems (navigation, climate control, odometer) cannot switch between English and metric units despite factory literature claiming this feature. Affects 2016 Prius vehicles manufactured January–February and delivered to US/Canada. Vehicle does not meet Canadian motor vehicle safety regulations as a result.
When: Present from manufacture; discovered upon purchase or early ownership
Symptoms owners cite: Unable to switch speedometer to metric units; Unable to switch nav/climate/odometer displays to metric or English; Vehicle non-compliant with Canadian safety regulations
Repairs/costs cited: No remedy offered except trade-in at owner's expense
Recalls/TSBs owners mention: Toyota offered only vehicle replacement purchase (at owner expense) after 10 months; no software fix provided
Brake system warning lights and fault codes (intermittent)
Sudden illumination of brake-related warning messages and lights including 'braking power low,' 'pre-collision system malfunction,' 'ABS malfunction,' and 'lane departure alert malfunction.' Codes appear in memory but condition cannot be replicated by dealer. Resetting connector cables does not resolve issue. Over 15,000 miles, warnings came and went intermittently while driving city and highway.
When: Over 15,000 miles; intermittent over one year of ownership
Symptoms owners cite: Braking power low warning messages; Pre-collision system malfunction light; ABS malfunction warning; Lane departure alert malfunction; Blind spot monitor malfunction; Warnings appear intermittently then disappear
Codes mentioned: C1403, C1407, C1415, C164D, C1A50, C1A45, P157800
Repairs/costs cited: Dealer only reseated connector cables; no parts replaced; no resolution achieved
Recalls/TSBs owners mention: Toyota customer assistance contacted; no change in position; owner negotiating trade-in
Rodent damage to wiring and harnesses
Soy-based wiring coating attracts rodents that chew through electrical wiring, fuel lines, brake lines, and sensor lines. Damage includes brake lines (3 of 4 in one case), O2 sensor lines, fuel line sensors, and possibly fuel pump wiring harness. Repair costs exceed $1,600–$2,700. Toyota refuses to pay for damage or replace wiring with non-soy material. One owner driven with only one working brake line before check engine light appeared.
When: Varies; one case at less than one month ownership; another at unknown mileage
Symptoms owners cite: Check engine light illuminated; Brake lines chewed through; O2 sensor line damage; Fuel line damage; Fuel pump wiring harness damage; Rubber odor from vehicle; Loss of vehicle operation
Repairs/costs cited: $1,680 to $2,700+ for wiring replacement; warranty does not cover rodent damage
Recalls/TSBs owners mention: Toyota denies responsibility; refuses to replace with non-rodent-attractive material; states this is a known issue among other owners
Hybrid battery overheating / coolant system warning
Hybrid battery becomes extremely hot while vehicle stationary, or 'hybrid coolant system needs service' warning illuminates unexpectedly. In one case, battery compartment filter system required cleaning to prevent battery overheating; vehicle deemed unsafe to drive.
When: At 7,000 miles (one case); at 20,000 miles (another case); while stationary
Symptoms owners cite: Rubber odor emitted from vehicle; Hybrid coolant system warning light; Battery compartment overheating concern; Vehicle unsafe to drive
Repairs/costs cited: Battery compartment filter cleaning required in one case; battery compartment filter system maintenance needed
Recalls/TSBs owners mention: Not repaired in all reported cases; manufacturer made aware
Battery drain / no-start condition
Vehicle fails to start or restart. In one case, opening driver door initiated loud noise from under hood (described as 'something would explode') that drained entire battery while vehicle stationary. Another owner's battery changed twice by dealer but vehicle still has no power. Vehicle has been towed multiple times.
When: Less than 18,000 miles (one case); timing variable in other cases
Symptoms owners cite: Vehicle will not start; Flashing warning lights followed by no-start; Loud noise under hood from driver-side when door opened; Complete battery drain while stationary; No signs of life in vehicle
Repairs/costs cited: Battery replaced twice in one case without resolution
Hybrid system malfunction / power loss while driving
Vehicle loses power, steering stops operating, and hybrid system malfunction warning illuminates while driving at highway speeds. Engine wiring harness failure diagnosed. Hybrid battery may recharge but wiring harness replacement needed. Another case: vehicle loses power at 66 mph; blown fuse and water pump failure diagnosed.
When: At 159,141 miles (one case); at 223,601 miles (another case)
Symptoms owners cite: Steering wheel stops operating; Vehicle begins to shut down while driving; Hybrid system malfunction warning light; Yellow blinking light on instrument panel; Vehicle deceleration and power loss in traffic
Repairs/costs cited: Engine wiring harness replacement needed (not completed); blown fuse and water pump replacement diagnosed in another case (not completed)
Recalls/TSBs owners mention: Manufacturer made aware in one case; did not assist
Unintended acceleration while parking / brake system failure
While parking and slowing to enter space, engine revved loudly and vehicle accelerated uncontrollably despite brake pump attempts, gear shift attempts, and releasing brakes. Vehicle would not stop at all. Owner steered to avoid obstacles but vehicle jumped curb, struck tree and concrete post, and came to rest on its side—total loss.
When: While parking (low speed situation initially)
Symptoms owners cite: Engine revved loudly during parking; Vehicle accelerated despite brake application; Brakes did not respond to pumping; Transmission would not shift to park; Uncontrollable acceleration
Repairs/costs cited: Vehicle was total loss after impacts
Vehicle stalls on acceleration / low battery warning after rain or car wash
Vehicle stalls when coming to stop and on acceleration, particularly after rain or car wash. Loud noise from engine, rapid battery bar drop from full to one bar in one second. Vehicle will not move at traffic lights when it happens. Occurs 10 times since June 2017, once weekly lately. Dealer unable to diagnose after multiple 5-hour service visits.
When: Since June 2017; once per week by report time; after rain and car wash events
Symptoms owners cite: Loud noise from engine; Vehicle stalls on acceleration; Battery gauge drops from full to empty in one second; Vehicle will not move from traffic light; Happens after rain or car wash
Repairs/costs cited: Dealership unable to find cause after two 5-hour service sessions
Recalls/TSBs owners mention: No resolution provided
Synthesized from 22 NHTSA owner complaints — unverified consumer
allegations, summarized for patterns. The verbatim filings appear below.