2018 Nissan Altima: What to check before buying

A failing brake light switch is the most common electrical fault. The car won't start or shift out of park, and the brake lights can stop working while driving, which one owner links to a rear-end crash. Replacement switches often fail again. Door lock actuators also fail, so rear doors won't lock or unlock with the fob or the interior button. Other reports cover airbag lights caused by bad occupant sensors, false forward collision warnings, battery terminals that corrode until the car stalls, and an overhead console that falls out while driving.

An airbag warning light stays on or flickers, often starting around 33,000 to 35,000 miles. Dealers commonly find code B0020-13, an open circuit in the wiring to the driver seat side airbag. The repair can mean replacing the whole upper seat back, quoted at $2,500 to $3,000 or more. Owners report waiting months for seat parts and driving without working airbags in the meantime. Light-off fixes often don't last. Two crash reports say the airbags did not deploy, including a head-on collision that left the driver with a head injury.

The CVT fails, usually between about 68,000 and 100,000 miles. Symptoms include shuddering, slipping, RPMs surging up and down, jerking, hesitation followed by a lunge, and a sudden loss of power on the highway. Some cars drop into neutral or roll back on a hill. Warning lights often stay off until the transmission has already failed, and dealers often find code P17F0. Owners past warranty have paid for the repair themselves or been offered partial goodwill. Some dealers could not reproduce the problem. A few owners also report popping from the front axles.

Most of these reports involve the front radar. A "front radar unavailable due to obstruction" message appears with nothing blocking the sensor, and it shuts off automatic emergency braking. The radar also brakes hard with no car ahead, including at highway speed and once for blowing leaves. Recalibration often doesn't fix it, and owners out of warranty were quoted about $1,000 to $1,200. Separately, faulty brake switches stop the car from starting. Two crash reports describe a pedal that sank to the floor or a car that would not stop.

Control problems vary with no single cause: a loose wheel that wanders and worsens on the highway, shaking in turns, clicking or popping noises, stiffness, or a sudden loss of power steering mid-turn. Dealers often find nothing wrong, and one replaced the power steering pump only to see the trouble return. A rental car became uncontrollable at 70 mph. Several filings here are really the same false front radar obstruction warning reported in other categories. One crash involved a slide on snow and ice after a low-tire warning.

Low-beam headlights are too dim to see the road at night, and many owners drive with high beams on to compensate. Some owners blame heat from the halogen bulbs, which they say fogs or melts the reflectors inside the headlight housing. Changing bulbs, including LED replacements, does not fix it. Some cars burn through low-beam bulbs quickly. Others develop cracks in both headlight housings that let water in, and owners say that repair wasn't covered by warranty. Faulty brake switches can also leave the brake lights dark.

These filings mostly describe waiting on the hood latch recall, campaign 20V315000. Owners received the notice, but dealers had no parts, and many owners hadn't seen a failure yet. When the latch does fail, the hood can unlatch while driving and fly up. In one case it hit the windshield and cracked it at about 35 mph. Another owner reported a hood ajar warning followed by the hood opening on the road.

False radar obstruction warnings shut off automatic emergency braking and adaptive cruise control, sometimes every few minutes on long drives. One dealer found radar blockage codes, tried reprogramming without success, and quoted $1,637.86 for a new unit. Other reports describe a lag or clunk when pulling away from a stop, sometimes followed by a jerk, and dealers often cannot duplicate it. Brake switch failures also show up here, with one owner reporting back-ordered parts that left the car unusable.