I downloaded two recent nissan tech bulletins for the NAH from nissanhelp.com - attached below - and they look ominous.

They both deal with the MIL coming on.

NTB10-056a deals with NAH from 2007 to 2010 with over 15,000 miles.

It reads in part:

• HEV vehicles have unique operating characteristics. The internal combustion engine has a higher frequency of start/stop cycles than a conventional vehicle.

• Under certain customer driving patterns this high frequency of start/stop engine cycles can result in increased carbon build up on the exhaust valves and/or exhaust ports. Sometimes these carbon deposits may cause the engine to run rough.

The amount of carbon build up is highly dependent on the driving pattern of the customer.

Their solution is to replace the whole cylinderhead and exhaust manifold.

NTB10-057 deals with NAH from 2007 to 2009.

It reads in part:

1. Replace the Vent Control Valve.

2. Install the Filter Kit listed in the PARTS INFORMATION section of this bulletin on Page 2.

It requires that the rear supension be removed to access the valve.


I haven't had either of these problems but I would hope that maybe they would be covered under the emission warranty(?). In Massachusetts, at least, you can't pass the emission test if the MIL is on.

I've decided to keep running lots of Techron in the gas tank - at least once every 2,000 miles to maybe prevent the carbon problem.

 

Our 2007 NAH MIL came on at around 23,500 miles in mid-May 2010, roughly 6 weeks out from expiration of its 36-month warranty. The Evanston IL Nissan dealer read the code as an evaporator vent control valve issue, and replaced it. About 150-200 miles later (late-May), the MIL came back on with the same diagnostic code (vent control valve). Finding nothing wrong with the vent control valve, the dealer reset the computer. After another 150-200 miles (mid-June), the MIL came back on; another trip to the dealer revealed the same computer code (vent control valve); dealer did nothing but reset the computer. After another 150-200 miles (late June/early July), you guessed it, the MIL came on (same code). By this time, late June, the dealer replaced the Vent control valve a second time and reset the computer. After another 150-200 miles (mid-July) --are you getting tired of reading this yet?-- the MIL came on. The dealer reviewed the MIL, and having found the same code, simply reset the code. In late-July or early-August, after our warranty technically expired, the MIL came on; by this time, however, the dealer got the bulletin and replaced the vent control valve and the in-line filter at no charge to us. After another 150-200 miles (mid-August) ---do you think we still like our NAH??--the MIL came on. Though I am not a NAH guru, I can tell you that the code will read the same as before. So we turned to our local Nissan Customer service rep who directed us to a Nissan dealer in St. Charles IL having a NAH-certified technician on staff (recall, we are in Illinois, which is not a state that sells or services the NAH). Last Friday, they read the computer, and got the same code as the Evanston Nissan dealer. So everyone is scratching their collective heads and contacting Nissan Command for answers.

Does anyone out there have any similar stories and if so, alternative solutions to this issue?? Thanks much.

 

What is the "MIL"?

 

For me, MIL generically means "maintenance indicator light". On the NAH, it specifically corresponds to the yellow "service engine soon" indicator.

 

So, nothing to worry about unless the light comes on, then?

 

Yes. We are just trying to figure out why our NAH's MIL always comes on with such regularity (150-200 miles after servicing the MIL code for the EVAP vent control valve). As much as we regret to say this, we can't be alone on this problem!

 

Other forums seem to suggest that you check that you have tightened your gas cap. Make sure it clicks 3 times.