Help Service Engine soon light

Good afternoon,

1 have a 2006 nissan sentra about 58,100 miles. The car recieves the regular oil changes. I got a service engine light and a mechanic saw it. He scanned the car and nothing came up as a cause so he cleared the light. The light has popped up again. What can I do ? How much will this cost? Help. I don’t trust the dealership since they charge an “arm and leg”, thank you, liz

Take it to somewhere like Autozone and have them read your stored codes. Post them here. Post the code numbers, not the shop goober’s interpretation of what they mean. They will look something like “P0131”

I am going to guess that it is P1116. Let us know when you find out.

Check in your owner’s manual and see if this is a warning light or a “service engine soon” light. An SES light will not store codes, and if it is that the owner’s manual should tell you how to reset it.

Post back.

SES Service Engine Soon

Same thing as “check engine light” or MIL

There will most definitely be a stored code.

It is NOT maintenance reminder light, if that’s what anyone may be thinking

Nissan as well as mine and others use a seperate light for the SES reminder than for an engine malfunction.

GM uses a service engine soon light

It is NOT a maintenance reminder light

It is THE check engine light

Thank you everyone. I took to dealership today after $110 to run tests the stored code was p0128 . They are telling me I need to replave the O2 sensor for the rear of the car and the cost is $ 640 . Please help, Thank you

Sorry that is P0138

If it was any other car but a 2006 Sentra, I would agree. However, the connector for the rear O2 sensor in this car is located in a bad place and during the rainy season, it can get water in it, and that sets the code you are getting.

The very first thing that the factory service manual says for this code is to unplug the connector and look for water. I have seen water pour from this connection. BTW, that should have been part of the $110 they charged you. If all they did was read the code, they owe you a refund. That diagnostic fee is supposed to cover all the troubleshooting steps associated with the code, not just plug in the code reader and push a button. AutoZone would have done that much for free.

yeah, just change the O2 sensor yourself, or have them do it. You already passed on a free sensor reading from Autozone, so just get it professionally replaced.

I’m not being smug here.

Some of you didn’t believe me what SES means.

Let the 2006 Sentra owner’s manual do all the talking.



I still learn new things every day

I hope my post will be seen as a learning experience, not an attack

Db, I’m sold. I stand corrected.
I could have SWORN…but I suppose that would have been another swear wasted.

You’re a good man.


No problem

It could be a faulty O2 sensor. But before replacing the sensor, the associated wiring should be checked for shorts, esp from the sensor wire to the battery voltage. That can trigger this code. I assume this is a heated sensor, so a test should be done to prove that the heater circuit is working correctly and that the heater element in the sensor is not open. Finally, a test should be done to prove that this isn’t being caused by an overly rich fuel/air mixture. If the O2 sensor is replaced but the mixture remains overly rich, it could damage the cat, which would result in another big expense.

I never doubted you db. My son has a 2006 Sentra and he has all the factory service manuals, all six of them. He has also had this code several times in the past. The first step in the trouble shooting procedure according to the factory service manual is to unplug the connector and check for water and every time he has had this code, it was due to water in the connector. He got so fed up with it that he cut out the connector and soldered the wires together and wrapped them in heat shrink. Hasn’t had that code since.

@keith so the connector itself was the problem?

I suppose that could make sense.

When I was working at the Benz dealer, there were several SRS lights that were fixed by cutting out a connector and soldering wires directly together. In fact, that was the factory fix. There was even a TSB instructing the mechanics to do this.

It was more like the location of the connector than the connector itself. It was low, in front of the engine but not protected by the plastic shield that is supposed to keep water off the accessories.

IMO, it is a design flaw in an otherwise pretty good little car.

I appreciate all the advice. I got the 02 rear sensor replace. The car was fine then 2 days later the pops up again. THis is beyond frustrating. If I was good at fixing cars or doing myself I would not bring to mechanic. THis is such a pain in the butt. What to do next?


Are you getting the exact same fault code?