2018 Nissan Sentra: What to check before buying

The CVT fails outright, often with no warning light beforehand. Cars jerk when shifted into drive, hesitate, judder, overheat, drag with a loud noise, or let the RPMs rise and fall at a steady speed. Many reports end with a sudden loss of power in traffic or a car that moves only in reverse. The usual fix is a full transmission replacement, and some rebuilt or replacement units fail again. Several failures land just past 60,000 miles, after the warranty ran out.

The push-button start fails to crank the engine, sometimes for 20 minutes, and drivers end up stranded in parking lots or on the road. Pressing the brake pedal several times sometimes gets it going. Owners blame the brake switch, and a new battery does not fix it. The front radar also throws false obstruction and collision alerts, and on the interstate it can shut down traction and stability control. One crash report blames a radar malfunction. Fuel gauges that show range remaining when the tank is empty also appear.

Two faults dominate. The automatic emergency braking radar reports a front obstruction that does not exist, sometimes within days of purchase. Some cars slow down even while the driver presses the gas. Dealers replace, clean, and recalibrate the sensor, but the warning keeps coming back. The second fault is the brake light switch, which leaves the push-button start dead and the brake lights off. Some replacement switches fail again the same day. Two fire-related reports describe a smoking brake and a burning smell while driving.

The front radar shuts off or gives false alarms with nothing ahead. When the radar is down, cruise control, collision warning, emergency braking, and pedestrian detection stop working with it, for anywhere from a few seconds to 10 minutes. In some cases the car brakes or stops on its own, including at 30 mph and in rain. Replacing the sensor and bracket often does not end the problem. Owners report out-of-warranty repair quotes around $2000. Complaints run from under 1000 miles to about 59,447 miles.

Most of these reports are about recall 21V135000. The recall covers a brake light switch fault that can leave the brake lights dark and keep the car from starting. Many owners got the recall notice but could not get the repair because parts were unavailable, and several say the wait ran past a reasonable time. Brake lights that fail to come on appear in crash reports, including a rear-end collision that caused a concussion. Failures cluster around 66,000 to 79,000 miles.

Airbags fail to deploy in frontal and barrier collisions. These reports include seven crashes and six injuries. Several also describe seat belts that did not hold properly or a driver's seat that collapsed backward, so occupants struck the steering wheel or windshield. A separate pattern involves the passenger airbag staying switched off even with an adult in the seat. Dealers trace this to a faulty occupant classification sensor and control unit, and a reset does not cure it.

Most of these reports describe CVT trouble again. The car shudders, sputters when pulling away, loses power, or will not drive forward. Dealers call for a full transmission, with one replacement quoted at $5500. Other reports describe a no-start where the electronics power up but the engine will not turn over, a stall going uphill with the emergency braking warning lit, and a vent control valve that failed again after replacement. One report describes a fire while driving that injured the driver.

Two problems split this group. In the first, the CVT stops pulling, stalls when the driver accelerates, or drives only in reverse. Owners past the warranty or over 80,000 miles say the dealer will not repair it for free. In the second, the front radar applies the brakes with nothing ahead, at different speeds and on the freeway, or shuts off with an obstruction message that also disables intelligent cruise control. One out-of-warranty sensor quote was $1300. One crash report cites failed collision avoidance and an accelerator that seemed to stick.