A/C may lock Leaf


By Jim Taylor, Editor MACS ACtion Magazine

Nissan Motor Co. has acknowledged that some of its all-electric Leaf vehicles can be stranded by an air conditioning related problem. The problem seems confined to a small range of serial numbers, but the company is uncertain of which cars are involved. The problem has been reported by Leaf owners in both Japan and the U.S.

The problem begins with the apparent normal use of the air conditioning, either to pre-cool the car or while driving. After some period of use, a number of warning symbols light up on the dashboard including electric vehicle fault, power steering, and battery. At this point, the Leaf will still operate correctly, but many (most?) drivers are intimidated by the array of warnings.

In most cases, the correct reaction to a Leaf fault light is to pull over, shut the car off, and restart it thus allowing everything to reboot. But with this fault, that’s the fatal mistake—owners report being stranded when the car will not restart or recycle at all. 

 

Nissan said it was investigating the exact cause, but said it traces back to the Leaf’s air-conditioning system. At present it is unclear as to whether the root of the problem is system related,  due to a faulty sensor, or due to incorrect programming of the computers that react to the sensor’s input. Nissan emphasized they would only comment when the exact cause and its solution was known.

While unverifiable, information found on the owners’ forums is enlightening. Some owners have reported their dealers as stating that “the A/C was overcharged at the factory” as the cause. Others say they were told one of the sensors was seeing a high-voltage short to ground within the compressor even though testing showed no such condition. Many report the dealers are already re-flashing the cars to upgrade the software, probably to expand the acceptable range for the sensor signal sent to the main control computers.

A small number of owners also posted that disconnecting the 12-volt negative battery cable for about 10 minutes allowed the car to reset and restart, but in doing so they also lost all their other settings including radio, GPS and similar on-board memories.

Nissan wants the Leaf to be successful and has been watching the U.S. cars carefully. Owners report excellent response from dealers when the cars enter this self-protection mode. If owners note this problem during or just after A/C use,  the factory advises them to drive directly to the nearest dealer and to not shut the car off until they arrive.

We say: Any new car will have its bugs, and this one will be interesting to watch. But the possibility of a sensor seeing a voltage leak or short at the compressor reminds how important it is to use the correct POE oil during A/C repairs on any electrically-driven compressor.

When having your mobile A/C system professionally serviced, insist on proper repair procedures and quality replacement parts. Insist on recovery and recycling so that refrigerant can be reused and not released into the atmosphere.

If you’re a service professional and not a MACS member yet, you should be, click here for more information.
                                   

You can E-mail us at macsworldwide@macsw.org or visit http://bit.ly/cf7az8 to find a Mobile Air Conditioning Society member repair shop in your area. Visit http://bit.ly/9FxwTh to find out more about your car’s mobile A/C and engine cooling system.

The 32nd annual Mobile Air Conditioning Society (MACS) Worldwide Convention and Trade Show will take place January 18-20, 2012 at the Rio All Suite Hotel and Casino in Las Vegas, NV.

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About macsworldwide

Mobile Air Conditioning Society (MACS) Worldwide Founded in 1981, MACS is the leading non-profit trade association for the mobile air conditioning, heating and engine cooling system segment of the automotive aftermarket. Since 1991, MACS has assisted more than 600,000 technicians to comply with the 1990 U.S. EPA Clean Air Act requirements for certification in refrigerant recovery and recycling to protect the environment. The Mobile Air Conditioning Society (MACS) Worldwide’s mission is clear and focused--as the recognized global authority on mobile air conditioning and heat transfer industry issues. www.macsw.org
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