Engine codes and repairs

[240femme]

I pulled codes from my ecu today and got a code 32 and a code 34. I read these were for the knock sensor and EGR system. I failed emissions the other day for high HC and CO. I guess the EGR problem would explain my results? Anyway, I would like to know what I need to do to fix these two problems that the codes correspond to. How do I replace a knock sensor? Also, I realize there are a few different components to the EGR system. Should I replace everything, or is there a particular component that would most likely be the problem? Before my check engine light came on, I was also wondering if I had a leaky injector. Should I still worry about that, or would that have had a code along with it?

[s13sr20chris]

the knock sensor code will not set a check engine light or influence your emissions. an egr problem would most likely cause you to fail emissions for NOx. if you have high HC and CO, you are running rich. this could be a leaky injector. if you pulled your plugs and just one of them looked fouled then it would point to a leaky injector. clean the ecm grounds on the intake manifold and check the maf ground circuit.

[240femme]

Actually the knock sensor does cause the check engine light to come on, I'm afraid. I read it right off the list along with code 32 which corresponds to the EGR system. I did change the O2 sensor after the emissions test failure and before the check engine light came on for the EGR. I have been told it is common to see this. I just need to know how to fix it. If it's just the valve, I was wondering if it's possible to just clean it and how I would go about doing that.

[NISTECH]

The knock sensor will NOT trigger a check engine light on any Nissan. The reason your light is on is due to the EGR code. Once you fix that and drive it a bit the light will go out even though the knock sensor code is still present. The knock sensor is not an federal OBD requirement to trigger the light. I have a post covering EGR operation for an emissions failure due to NOx. heres a link to it.

http://www.nissaninfiniticlub....72750

[240femme]

What is code 34 then? I am getting both 32 and 34. I read here http://www.240sx.org/faq/artic...h.htm that 34 is the knock sensor, but if that's not it, I'd like to know what is causing that code. Thanks for the link to the EGR info.

[NISTECH]

That is for the knock sensor. But it is not the code thats turning on your check engine light. The code 32 is the one turning on the check engine light. Once you fix your code 32 the light will shut off even though the code 34 still remains. If you check for codes after the light goes out you will find code 34 is still in there but the light wont be on.

Hope that didnt confuse ya even more:D

[240femme]

No, that makes sense. I guess I figured since the light was on, both problems were causing it...or rather either one would do it by itself. Should I worry about the knock then?

[NISTECH]

Not having the knock sensor functioning can cause a slight loss of power mainly on mild to moderate accel. What the sensor does is prevent the engine from pinging on accel. It allows the engine to advance as much as possible with out pinging. once pinging/detination begins it backs the advance down a bit to stop it. When that code comes up it goes in to a predetermined /failsafe advance setting which is substantially less then what the timing is capable of doing therefore causeing the lack of power. What is likely wrong with it is its cracked from the heat or it has an open circuit between the sensor and the subharness attached to it. It is best to replace both the sensor and the subharness as a set. you can gain access to the sensor if you remove your oil filter and look up under the intake manifold. It is held to the block with a 12mm head bolt

[s13sr20chris]

its a good idea to fix that. its not expensive either if i remember correctly.

[NISTECH]

the sensor itself is $123.06 from pinnacle, not sure on the harness think it runs about $15

[s13sr20chris]

oh, i thought they were cheaper than that. oops.

[Maverick7687]

I just went and checked the codes on my 1993 240sx and the only code I got was a 34 Knock Sensor Which in fact DID make the Check Engine light come on.. But, it only came on when the key was in the ON position, once the engine was started it went off. After I reset the ECU and turned the key back on the CE light was off. Anywas, Knock sensor replacement it is I guess for me.. Mav

[240femme]

I think when the key is in the on position, the check engine light is on no matter what...in fact, aren't all the lights on at that point?

[Maverick7687]

well, the CE light should go off I think...after a few seconds, I could be wrong, been wrong before. But i only have 3 lights on when key is in on position

[NISTECH]

the light is suppose to come on till the engine is started as a bulb check. your ecm may have still been in a diag mode when you first turned the key on after clearing the code. The next time you turn your key on take note the light stays on till you start your car.