The eight-speed's first year, and the loudest Sienna in this range — drive the transmission before you sign.

This is a Customer Support Program, not a safety recall, so it will not show up if you simply search the VIN for recalls — you have to ask a Toyota dealer about it by name. Toyota's wording: it has 'received reports about potential symptoms, such as a whine noise from the transmission while driving, harsh shifting, reduced power, and master warning light/check engine light illumination, in the subject vehicles that are equipped with a model UA80 transmission', caused by a washer tab that 'was not sufficiently bent during assembly'. Read the coverage line carefully. Toyota's bulletin states that the UA80 is covered by the New Vehicle Limited Warranty for five years or 60,000 miles — that is the ordinary factory warranty, long expired on a 2017, not the program. The bulletin summary never states how long the program itself runs or what mileage it reaches. So: verify the terms in the bulletin PDF and, more importantly, ask a dealer to check your specific VIN against it before you buy. Owners in the federal file repeatedly report being refused — 'my VIN was not included in the Customer Support Program', 'the dealer says this car is not covered' — and one writes that Toyota 'knows about this issue with thousands of cases regarding the faulty transmission, yet only a few are being covered'.

The most serious safety recall on this year. Toyota found that the oil galley inside the brake booster vacuum pump's rotor 'may have been improperly machined, possibly resulting in a sudden loss of brake assist' — meaning the pedal suddenly goes hard and stopping takes much more effort. It covers 2017 Sienna and Tacoma, 2018 Camry and Highlander, and the 2017 Lexus RX350; Toyota's internal codes are J0K and JLD. Dealers replace the pump free. Repairs began in May 2018, so most vans have had it, but confirm it against the VIN rather than assuming.

The 2017 Sienna is caught by both halves of Toyota's low-pressure fuel-pump campaign: 20V-012, the original, and 20V-682, the expansion that explicitly names 2017–2020 Sienna (Toyota code 20TA02). The failure is straightforward and dangerous — the pump inside the fuel tank can quit, and 'if the fuel pump fails, the engine can stall while driving'. Dealers fit an improved pump free. There is a second layer worth knowing: a federal court approved a settlement on 20 December 2022 that requires Toyota to run a Customer Support Program for certain 2014–2020 vehicles whose low-pressure fuel pumps were repaired under this recall. The program's terms are not stated in the bulletin summary, so verify them in the bulletin PDF. If you buy a 2017 that stalls after having had the recall done, that program is the first thing to ask about.

The third-generation Sienna's power sliding doors fail in four recognised ways: the cable that pulls the door snaps (you will see it hanging above the rear tyre), the centre hinge corrodes so the door jams as it finishes closing, and the front or rear lock assembly seizes so the door will not latch. A class-action settlement produced Toyota's Customer Confidence Program ZKI, plus Warranty Enhancement Programs ZH4 for the front lock assemblies and ZH5 for the rear. Toyota's bulletin states the terms plainly: the cable sub-assembly, centre hinge and fuel-filler door are covered for '10 years from the subject vehicle's date of first use, regardless of mileage', and ZH4 and ZH5 run nine years from first use plus one more year, also with no mileage cap. On a 2017 those clocks are about to run out or already have. Our mechanic source's advice is worth repeating: before paying any independent shop for a door repair, phone a Toyota dealer and ask whether an extended policy still applies to the VIN.

The 2017 V6 is the direct-injection version, internally the 2GR-FKS, and Toyota has two bulletins about it leaking oil. One covers an oil leak from the camshaft-sensor bolt holes on 2017–2018 Sienna and Highlander. The other covers a leak from the No. 2 oil pan on 2017–2020 Sienna and 2017–2022 Highlander, narrowed in a later revision to engines whose serial number begins with F or G; Toyota lists it as 'currently under investigation' and asks technicians to photograph the leak before repairing it, which tells you the cause was still open. Separately, our mechanic source says the water pump on this engine keeps leaking despite a claimed 2017 update — 'I've replaced a bunch of them already on 17, 18, 19s' — and that the external head-gasket coolant leak that plagues 2011–2016 vans is less common on the updated engine but that he expects it may simply be a matter of time. Get it on a lift and look for oil and coolant before you buy.

Budget for suspension. Our mechanic source describes leaking front struts as near-universal on this van and explains the cause: water running off the windscreen collects in the cowl and sits on the strut mount, rotting it from the inside. He also flags front lower control-arm bushings wearing quickly, with a test you can run yourself — at low speed, hands resting lightly on the wheel, brake hard; a sharp jump to one side means the bushings are gone. Four of the ten recalls on this year are not Toyota's: Braun's brake-line fittings (19V-410) and steering-shaft extensions that can fracture (19V-532), Vantage's short rear brake hoses (19V-553), and Rollx's wheelchair-restraint retractors (25V-876). They apply only to vans converted for wheelchair use, which is a meaningful share of used Siennas — check the VIN if the van has a ramp or a lowered floor. Three more are load-capacity-label corrections (17V-831, 19V-503) and a Gulf States spare-tyre pressure recall (17V-295); all free, all housekeeping.