Toyota Sienta common problems: what to check before you buy
Credov's researched list of the 13 faults the Toyota Sienta is known for (2015–2022), 12 of them serious or costly. Each one says what to look for when you check the car, so you can spot it before you buy. Not every car has these faults: they are the ones worth checking on this model.
Known problems on the Toyota Sienta
Hybrid 12V charging fault
Safety risk
2018 · 1NZ-FXE · hybrid · Hybrid and EV
What to look for: Look for a 4522 recall sticker in the driver's door opening, then leave it in READY and watch for warning lights.
Why it matters: The MLIT notification states that insufficient soldering on the converter's control board can separate under repeated heat cycling, stopping the auxiliary battery from charging, illuminating warning lights and, in the worst case, shutting the hybrid system down so the vehicle cannot be driven. On a Japanese import there is no NZ owner record to notify, so an outstanding campaign follows the car into your yard.
What to look for: Listen for a slow, laboured crank or just a click when starting from stone cold, and again when hot after the drive.
Why it matters: The MLIT notification states that inadequate tightening instructions let the starter through-bolt loosen over time, shifting internal components and reducing starter output; continuing to use it can leave the engine unable to start, and repeated cranking in that state can overheat the starter with a worst-case fire. MLIT recorded 13 occurrences including two fires.
What to look for: Look for brake, ABS and skid warning lights staying on together in READY, and feel for a very heavy brake pedal.
Why it matters: Toyota Japan's notice states that frequent braking can wear the hydraulic control valve in the electric brake actuator earlier than designed, that several warning lamps then illuminate together, and that continuing to drive brings on an audible warning with higher pedal effort and reduced braking.
What to look for: Look for both 4521 and 5131 recall stickers in the driver's door opening, and listen for a knock once warm.
Why it matters: The two MLIT notifications record that the cowl louver waterproofing was inadequate (first the louver itself, later the service-hole cover), so in heavy rain water drips onto the top of the engine and enters the combustion chamber through the injector mounting. The stated consequence is a deformed connecting rod producing abnormal noise and, in the worst case, engine failure leaving the vehicle unable to be driven.
2019–2024 · M15A-FXE, M15A-FKS · Suspension and steering
What to look for: Look at each front lower arm near the ball joint for rust or cracks, and listen for clunks over bumps.
Why it matters: MLIT No. 5340 records inadequate manufacture at the ball joint mounting leaving cracks that spread over rough roads until the lower arm fractures and the ball joint drops out, impairing driving stability. MLIT No. 5445 records inadequate durability against frequent de-icing salt, so corrosion cracks and spreads to the same end state, with the vehicle unable to be driven.
What to look for: Check the airbag light comes on then goes out, and look for a 4363 recall sticker in the driver's door opening.
Why it matters: The MLIT notification records that electrical noise immunity of the airbag control unit was inadequately assessed, so noise from the vehicle's electrical components can damage an IC chip inside the unit in service and, in the worst case, deploy the airbags while the vehicle is moving. An airbag firing unprompted at speed is a crash cause in itself.
What to look for: Look for a 4185 recall sticker in the driver's door opening or a Japanese record; a normal airbag light doesn't settle it.
Why it matters: The MLIT notification records that the manufacturing conditions for the IC chip in the acceleration sensor or the pressure sensor were inadequate, so an open circuit can form inside the IC; the airbag warning lamp then illuminates and the airbags cannot operate properly.
What to look for: Feel the carpet at the front pillars and sliding door sills for damp, and check each power sliding door works smoothly.
Why it matters: MLIT notification No. 5416 records that the waterproof durability of the front pillar garnish mounting clips is insufficient, so water enters the cabin over time and wets electrical connectors, causing faults such as door lock malfunction and, in the worst case, the power sliding door opening while the vehicle is moving.
What to look for: Ask the importer for a Japanese recall check on the chassis number, plus the auction sheet and any recall records.
Why it matters: The MLIT recall schedules behind the Japanese campaigns cited elsewhere in this overlay all state that the manufacturer notifies vehicle users by direct mail, with trade notification through the Japanese repairers' association journal and the manufacturer's own website.
What to look for: Feel whether the foot handbrake pedal moves sideways, and look for a 5416 recall sticker in the driver's door opening.
Why it matters: The MLIT notification records that the tightening-torque instruction for the bolt fixing the pedal to the body was inadequate, so clamping force is insufficient, the bolt can loosen in service and fall out, and in the worst case the parking brake cannot be operated at all. Toyota's remedy is to check the bolt, re-torque it, or replace the pedal where the bolt has already fallen out.
2005–2015 · 1NZ-FE · petrol · Exhaust and emissions
What to look for: Pull the dipstick: low or very black oil on a car that was "just serviced" is a warning.
Why it matters: Light use is just a top-up habit; heavy use fouls plugs, can damage the catalytic converter and points to an engine rebuild or swap. Left unrepaired this grows into a major repair bill.
What to look for: Switch to READY: any hybrid system warning is a stop sign.
Why it matters: Blocked cooling intakes and dusty fans shorten battery life. Fixes are a rebuilt, used or new battery. Left unrepaired this grows into a major repair bill.
What to look for: Look around the catch in the driver's door opening for Toyota recall stickers, and photograph any numbers you find.
Why it matters: The instruction to apply a numbered sticker near the driver's door striker appears in the text of the Toyota recall notifications themselves, which makes it the one field marker a New Zealand dealer can read without a scan tool or a dealer account.
Got a question about a Toyota Sienta? Ask Credov: a noise, a warning light, a part or how to fix it.
Also check on every car
On top of the faults above, every Credov inspection covers the basics: fuel smell, leaks or filler rust, engine oil leaks, power steering fluid leak, drive belt cracks or squeal, rust underneath: chassis and mounts, engine mounts, engine oil level and colour, coolant level, colour and leaks, head gasket failure signs, cold start: rattle, knock or smoke, rough or hunting idle, engine running hot on gauge, gearbox or diff oil leak, swapped gearbox without lvv and more.
Researched by Credov from manufacturer recalls and service bulletins, owner reports and workshop sources. Repair prices are typical ranges, not quotes. See also fault codes and repair costs.