Some 2002 2.5-liter Altima and Sentra models are prone to turning on the Check Engine light and storing the following engine and/or transmission trouble codes in computer memory: P0131, P0132, P0133, P0134, P1144, P0731, P0732, P0733 and P0734.
Nissan said the codes can be accompanied by a low-power or poor-running complaint and are most likely due to premature failure of the front oxygen sensor.
A new sensor—part # 22690-8J010—is now available to address the problem. Before installing it, though, take a quick look at the exhaust manifold heat shield. If the shield looks like the one on the left in the accompanying illustration, replace it with the new-de-sign heat shield on the right, part # 16590-8J003.
Nissan said the updated heat shield has a cutout that allows better airflow around the replacement oxygen sensor, which should help prolong its life. If the engine already has the new-style shield in place, just go with the updated oxygen sensor.
Drivers of 1995-2000 Legacy models may come into your service bay complaining of a knock or rattle in the steering system. They also may comment that the noise is most prominent when turning and going over a bump, such as when pulling into a driveway from the street.
The most likely source of the trouble, according to Subaru, is the reactive force that takes place inside the rack from the impact of the tires hitting a bump. This causes the hydraulic pressure on the input side of the rack to force back against the lower residual pressure found on the output side. It's this higher pressure colliding with the lower pressure that causes the noise.
Subaru has come up with two separate and distinct fixes for the problem, depending on the model year. For 1995-99 Legacy models, install a new steering coupler U-joint with a built-in damper (part # 34160AC030 for conventional Legacys; part # 34160AC090 for Legacy Outbacks).
For 2000 Legacys, install new-design power steering lines, part # 34190AE120, which better absorb the pulsations caused by the pressure differential in the rack-and-pinion assembly.
“Factory Fixes” is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. Mr. DePalma advises that techs always check with a dealer or repair information system for the latest revisions before starting to work on a vehicle. He can be reached via e-mail at [email protected]