# Just got this Maxima and have multiple codes. Please help!



## gmjordan (Dec 29, 2017)

Hi,

I just acquired a 2002 Maxima with 145,000 miles on it about 2 to 3 weeks ago and at first it was running silky smooth even with the SES light on. Then after a week or so I noticed the SES light starting to blink sometimes. At about the same time I noticed that it was a little rough in acceleration but especially noticeable when starting from a dead stop. I can still get to highway speeds but the car is not quite as smooth. I think this may be hurting my fuel economy.

I took it to autozone and their code reader read the following codes:
P0300 (this one was shown twice, don't know why)
P1800
P0507

Their printout said the most likely culprit was the head gasket. Is this true or could it be a host of different things?

Thank you in advance for your help!


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## smj999smj (Jan 1, 2006)

Well, I don't see a head gasket failure based on the information you provided us. The flashing CEL is not good and is an indication of a condition that can cause damage to the engine; often, this is caused by an ignition failure, such a worn or faulty spark plugs or one or more bad ignition coils. The P1800 is usually caused by a bad VIAS control valve. Here's a YouTube vid that shows the valves location:






Last is the P0507 code, which can be caused by any of several things. Disconnecting the battery for a length of time or the fact that you have engine performance issues can cause this code to trigger. Also, sometimes this code can trigger due to a faulty idle air control valve, which, on the VQ35DE, can short circuit and cause damage to the ECM circuitboard. I think I would get a second opinion at a shop familiar with Nissans before I'd okay a head gasket repair, unless they can provide better proof that the gasket actually has failed.


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