4th Nov 2004, 22:23

$950 to replace a knock sensor!?!?! That's outrageous! It's a $120 part and 10-30 minutes of labor tops. What repair shop gave you this quote!?

7th Nov 2004, 08:42

I have a 99 Maxima and the "check engine" has been on since I bought it 3 months ago. It has driven fine, no problems, but was not getting the gas mileage that I thought I should be getting; therefore, I changed all the plugs (which were the originals) and installed a $40. lifetime air filter. The tune up really gave it more power. Two months later with the "check engine" still on the car would not start after sitting all night. The motor would crank strong, but would not turn over; replaced the fuel filter and checked the fuel pump and it was working. Finally took the car to a repair shop and a "knock sensor" code came up with two other codes, that is all the information I have recieved from the repair shop.. they are really busy and haven't gotten a chance to begin working on it. Although they did say that the knock sensor would not cause the vehicle to not start.

Anyone have similar problems? I am curious how much it is gonna cost me to when I finally get to pick it up completely repaired.

27th Jul 2005, 09:21

I just purchased a 1998 maxima and 3 days later my engine light when on. took it to auto zone great guys... told me the problem was a knock sensor and oxygen sensor.

Anyone know how much these parts cost. Also, how important is it to use a Nissan Part when repairing this problem.


10th Sep 2005, 19:14

I'll start by quoting the entry from March 16, 2004: "The internet is cool." True, and one such reason is that you can find anything on the internet. Anyone can do a Google search for a car and find out all about it -before- they buy it. If any of you had researched the '99 Maximas before or after buying one, you would know that they contain one of the top ten most relable engines ever built. One small flaw are the knock and O2 sensors that you are all complaining about. Also for the person posting on March 16: Plugging the O2 sensors is STUPID. As if that's not bad enough, leaving them that way for the sake of keeping the check engine light off and lying to someone interested in buying your car is highly immoral. You people need to start looking at things from a more intelligent perspective. Compare the relatively small and one-time repair cost of replacing these parts to all the money that would be spent replacing dozens of other parts in other cars. To the woman who originally posted: You did the right thing by having the sensors replaced. Your -mechanic- is responsible for the knock sensor problem that occurred -after- he "fixed" it (as well as overcharged you). That is not Nissan's fault, and is not a valid reason for not trusting their vehicles in the future. Everyone, please, just smarten up.

28th Oct 2005, 23:37

This is some great info. Thanks to everyone for posting it. I have 54K miles and my engine light came on. Now I'm fairly certain this is due to faulty sensors... That helps, but what do I do about it? Not sure I'd want to end up spending so much on it.

My take is that this just proves that the sensors, and the engine light are basically worthless, at least in a Maxima, as they fail to accomplish their purpose - to indicate a problem with the engine. That being said, I'd rather trust my instincts when it comes to judging the state of the engine. If its driving weird or making noise.. time to do something about it. I would say based on what I've read, that the risk is small...

11th Nov 2005, 00:07

In my state, if a sensor is not working or is disconnected, the car will not pass inspection. A car cannot pass with the check engine light on. The car is connected to the code reader to check the sensors and also must pass an active smog test with the engine running.

18th Nov 2005, 19:33

I'm wondering - has anyone replaced the O2 sensor on the exhaust pipe before the catalytic converter? If so, where did you purchase a replacement? How did you loosen it? It is very tight?

And, do you have any other tips on changing the sensor?

17th Jan 2006, 12:51

I have '96 Maxima, and have same problem with you guys: Knock sensor thing. "check engine light" always comes on. I replaced it at $340 ($189 part + $150 labor). After replacing knock sensor, check engine light came on again. This time it was coolant temp. sensor. It costs me $80 ($50 for part, $30 for labor). After doing everything I can do, the check engine light still comes on. It won't off. Finally I make up my mind that I will not spend any money and any time to fix the damn stupid sensor thing ever!

25th Jan 2006, 14:18

Just did the knock sensor on my 98 Max GLE. The part was $170 from Nissan, actually cheaper than other places. I did the repair myself and it's a bit tricky to do as access is difficult. Fortunately, I have a good set of tools, swivels, extensions, and patience - took about an hour. Nissan actually calls for the removal of the rear manifold which involves a lot of work and will add to the labor cost. Also, you should clean up the ground wires on the manifold or the problem can recur. Be sure the code (s) are cleared out of the ECU or you may get a false reading. If there is more than one code, follow procedures to eliminate certain codes in order or you may not resolve the actual problem. For example, if you replace the MAF sensor, you may trigger a knock sensor failure. In reality, the knock sensor code is sympathetic to the MAF code. Replace the MAF, clear the codes, and then recheck. Might not hurt to burn some higher octane or use a octane booster temporarily to burn out any excess carbon buildup in the engine causing an detonation problems.

29th Jan 2006, 11:35

OK, I own a 99 Maxima SE, 5 speed manual transmission. I too have replaced one coil (the number 5 as well). I would not characterize the car as "unreliable". Over 170,000 miles of ownership, the coil and starter have been the only non-routine repairs. Average mileage has been 27 mpg (mostly highway miles).

28th Mar 2006, 12:55

I purchased my 1999 Maxima brand new and have only had one issues since day one, the oxygen sensors. Not only have I had to have them replaced, I've had to have it done three times now. It seems as though every 18 month's this is happening. Thankfully I purchased an extended warranty with the vehicle and am still under the 60,000 mile threshold, but it seems odd that this is continually happening. Is there maybe something that my dealership is overlooking? I've had no other issues with the car and think its one of the best vehicle I've ever owned, but this is getting rather annoying.

29th Mar 2006, 00:04

^^Are you running premium only?? Any type of gas with less octane than 91 is bad for your engine/02 sensors/cat.converter. In reference to everyone else, a bad knock sensor WILL NOT set off the CEL! A knock sensor code is sometimes a "ghost code" meaning it could be anything. It is usually accompanied by one or more other codes. For example, a faulty coolant temp. sensor can also trigger the knock sensor code. A faulty vehicle speed sensor can cause the knock sensor code as well. As a matter of fact, all three of those things (and also faulty 02 sensors) will give what so many people complain about which is weak power between 1-3k rpm, or sluggish performance lacking torque.