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Discussion Starter #1
sorry but im having issues with my cousins car. she got the codes pulled and here is what they came up with. CODE READS P0325 KNOCK SENSOR 1 CIRCUIT P01743 BANK 2 SYSTEM TOO LEAN P1440 MANUFACTURER CONTROLLED AUX EMMISIONS CONTROLS REQUIRES EGR GASKET, INTAKE MANIFOLD GASKET, AND KNOCK SENSOR. AFTER LEAKS ARE FIXED FURTHER DIAGNOSIS IS REQUIRED FOR CODE P1440


now im assuming the want to replace all those gaskets to eliminate intake leaks? or is it they want to remove the intake to get to the knock sensor? she doesnt have the $987 they quoted her so im trying to help her out....any info would be greatly appreciated. she did say it has a newer knock sensor so ill take hers out and test it if i can.
 

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NF Mod/Nissan Master Tech
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Actually, it's an evaporative emissions small leak code, which "may" be a loose or faulty gas cap, but could be any small leak in the evaporative emissions system, such as a leaking fuel sender seal or a stuck open vent control valve.

The knock sensor could be caused by the lean mixture situation. Even if it is the knock sensor that's bad, removal of the intake manifold is not required. A long 1/4" extension and a 12MM universal socket and a bit of patience can be used to "sneak" the knock sensor out.
 

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Thanks for the reply! I will check the vent valve I read how to do that. And I was able to get the knock sensor out! Is there a way of testing it? I read across it and it measured 560kohms is that bad? When I get how from work I'll test the vent valve other than that all hoses seem to be in great shape. I spent a good while yesterday poking a prodding hoses! Again thank for your reply I definetly need the help!!!
 

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Discussion Starter #5
so i took the vent control vavle off and i can blow right thru it. is it normally open when unplugged and out of the car? i hope not so i can blame the vent hahaha
 

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ive done all the similar things with my max except the p1440, i had p1400, and my car is running lean at the moment, no clue why, but it shouldnt cost 900$ if u do the work yourself, i paid 132$ for knock sensor, like 16.99$ for all the intake gaskets, and 2.99 for egr gasket, my advice is do all the work at once because you need to take the intake plenum off to get to the egr valve. as for yr p1440, look at the solenoid(between intake plastics and front head), its the brown one i believe, check the hoses connected to that, well after u check yr gas cap
 

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Discussion Starter #7
thank you for your post! i actually did a missive cleaning....iacv, maf, throttle body, and while i had it all apart i noticed two thing.......for one the egr valve had blown out a gasket and the egr tube was missing one up top! i was kind of concerned at the amount of crud i had to clean and how black the untake is but oh well i turned it on and the car runs GREAT! hopefully a test drive will make it all worth it but that is gonna have to wait till tomorrow.
 

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For future knowledge, the vent control valve is normally "open" and is "closed" when voltage and ground are applied. Also, resistance for the knock sensor is approximately 500 - 620 k Ohms [at 25°C (77°F)] when checking with an ohmeter between ground at pin #2 of the knock sensor.
 

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Discussion Starter #9
Yes I actually talked to a tech rep and he walked me thru testing the knock sensor. It should read 5 volts with the ks plugged in and not grounded. Once you mount it the voltage should drop to like 2.5 volts. If no change the sensor is bad. And I did apply 12 volts to the vent valve and yes it shut lol. I'm learning ALOT!
 

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Get yourself a multi meter and get on utube and type in checking knock sensor on your car. they do go bad but with small hands an a lot of cuts (the gaskets are stainless steel and will cut you) they can be replaced without taking the intake manifold off the engine($600.00).

Otherwise have the fuel pressure checked. On these older cars the fuel pump can trigger the knock sensor code. I have a 1996 infinity with 268000 miles and it runs fine but does have problems with vacuum leaks which can cause a lot of problems. misfiling, poor gas mileage, pcv valve codes. Diagnosis in 1996 was in it infancy and OBT2 codes were also. The problem is often far from what it says.

I have also had to take the intake manifold off to replace the valve cover gasket. A common problem. I have had the transmission fluid replaced every 75000 miles. (synthetic)
 
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