I did a diagnosis with the check engine light and the ECU and I got 0103 and 0304. These codes say the coolant temp sensor went off and the knock sensor went off. THis has happened once before about a week ago, now it has happened again. DOes anyone know what is up with my car? I am putting good gas in (93 octane) and I just got an oil change and everything checked out ok. THe car seems to run fine. SHould I just bring the car into nissan and soak up the diagnosis and repair costs or is their anyway I can do a check up myself....How do I permenantly fix these problems on my own?

thanks

 

Here is some information about the Knock Sensor, taken from the '99 Maxima factory service manual.

1) Raise the hood. View the engine from the driver's fender. Look into
the deep valley between the cylinder banks and below the intake manifold.
Identify the KS as a black item fastened to the block by a single vertical
bolt. A wire harness wrapped in black leads toward you, out of the valley.
That is the KS sub-harness.

2) Follow the KS sub-harness to it's nearest connector. This is connector F-121.
It is located near the upper right-hand corner of the valve
cover of the forward cylinder bank, as viewed from the
front of the car.

3) Disconnect F-121. You have to do a "press the latch and wiggle and
pull" to disconnect it. F-121 has only two pins; if you see more than two
pins, you have the wrong connector. Use a digital ohmmeter capable of
measuring more than 10 Megohms. You want to measure the pins of F-121, not
the sockets of the matching connector. Measure the resistance between a
good ground (such as the battery negative terminal) and pin #2 of connector
F-121. On my car this is the highest of the two pins, the one closest to
the front of the car. The factory spec is 500 - 620 Kohms.

 

ok, well, I bought the coolant sensor and I am going to put it in my car today....is it possible that the knock sensor was set off by the temp coolant sensor not working. DOes the diagnosis saying soemthing about the temp coolant sensor mean that it needs to be replaced? why would both of these go on the check engine light at the same time? HTere must be some linkage.

 

You may want to test your Engine Coolant Temperature Sensor before
installing the new one. This is easy enough, requiring only an ohmmeter.

With the engine cold, disconnect the ECTS and measure its resistance.
Reconnect the ECTS, start the engine, run it until fully warmed up. Stop
the engine, and repeat the resistance measurement. The "warm" reading
should be a much lower value than the "cold" reading.

The Chilton Maxima shop manual gives these specs:
Engine coolant temperature 68F, ECTS resistance 2.1 - 2.9 Kohms
Engine coolant temperature 194F, ECTS resistance 0.24 - 0.26 Kohms
(Roughly a factor of ten difference.)

 

Not likely. The usual symptoms of a failed Engine Coolant Temperature Sensor are these:
(1) If the ECTS always sends a "warm engine" signal, the engine will be difficult to start when cold.
(2) If the ECTS always sends a "cold engine" signal, the engine will be difficult to start when warm. Furthermore, it will run rich. The consequences of an over-rich mixture may include:
- poor performance
- poor fuel economy
- black smoke at the tailpipe
- rotten egg odor to the exhaust
- catalytic converter unusually hot

A Diagnostic Trouble Code which aims the finger of blame at a sensor may be caused by a failed sensor, but also by a wiring problem associated with that sensor. The DTC is the way the Engine Control Module announces to the world "The XYZ sensor is sending me a screwy signal or no signal at all. Something is wrong out there, but I can't tell if the sensor is sick, broken, disconnected, or just in a bad mood. Mr. Technician, please look at that entire circuit and fix whatever needs fixing."

 

well, its been foru days and 100 miles of driving in the cold and lots of city driving and the car's ck engine light has not gone off again. I am assuming this was what was wrong, and if I am wrong then the next time the light goes off it is off to the money sucking nissan service center. And in response to the guy who called me a "technician" and I am assuming that was sarcasm...i dont appreciate that kind of sh-t. I need to save money because I go to school full time. I appreciate your help and all but please hold back on the insults.

 

I am the only person who posted in this thread who used the term Technician. It was not used with sarcasm, nor was it aimed at you. If you felt insulted, you are being defensive for no good reason.

Technician is the term currently in favor, replacing Mechanic, as a person who repairs cars. There's nothing insulting in either term. The Technician, or Mechanic, is a high skill specialty in these days of computer-controlled engines.

In this forum, and others like it, Technician refers to the man who repairs cars as his vocation. We use it in contrast to Owner. Some Owners may choose to pay a Technician to perform maintenance or repairs. Some other Owners choose to repair their own cars to save money, to learn more about how their cars work, and to take pride in self-reliance. I admire this kind of Owner. I am one of them.

 

I thought there was sarcasm in that...my apology. I guess it is one of the internet , no face contact sort of thing. I thought you were making fun of me. Anyhow, everything seems fine....thanks for your help.