A place to discuss hardware/software and diagnostic procedures

Pro Tip: Chevrolet Cruze Knock Sensor Codes

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3 years 7 months ago #42679 by Tyler
How quickly does the P0325 come back, exactly? Seconds after startup? After a test drive?

If it resets in seconds, then I'd take the plunge and get to the knock sensor for wiring testing. From Service Info:

Conditions for Setting the DTC

P0325

The ECM detects the knock sensor signal circuit is open for greater than 5 s.


Of course, there HAS to be more to this code than that. :silly: Neither the sensor or harness was electrically open when I found the chain guide loose, but it got fixed anyway.

I'd suggest some voltage checks first, KOEO, sensor disconnected. DMM connected to B-, what voltage do you find on both knock sensor wires?

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3 years 7 months ago #42707 by JKUman
Hey Tyler..sorry for late reply. I have a hard P0325 set in the ECU but I can clear the CEL and sometimes get a day or so before it comes back. I've crawled back up underneath and the wiring to that sensor still has the wire loom and black electrical tape on it so I can't tell if there's any breaks. Everything is connected and appears solid. It conjoins with the starter wiring and O2 sensor and heads up over the fuel injectors to one large main harness. I'm not very handy when it comes to DMM and testing circuits. What is KOEO? DMM connected to B-? I can hear a slight knock from what appears to be the valve cover area. It's not consistent but every few seconds. Now I'm wondering if something with valves?

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3 years 7 months ago #42961 by JKUman
*bump*... could really use some help if possible. If I take it to a shop, will they be able to dive deeper into ECU? Again.. I have a hard code set that I cannot clear. Wondering if I should purchase another knock sensor and try that in case the first one was bad? (wasn't fun to swap but could do it without removing intake manifold). I'm all ears... about ready to do a country torch on this thing.

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3 years 7 months ago #43041 by Tyler

JKUman wrote: I'm not very handy when it comes to DMM and testing circuits. What is KOEO? DMM connected to B-?


Sorry about that. :blush: KOEO is Key On Engine Off. Digital Multi Meter connected to the battery negative post.

I asked about the voltages on both knock sensor wires because the code suggests that the knock sensor circuit is open. Voltage checks at the knock sensor might prove or disprove that.

The fact that you can clear the code and not get it back for a day or so means it isn't a hard fault, and likely isn't a complete open/short in the wiring.

I can hear a slight knock from what appears to be the valve cover area. It's not consistent but every few seconds. Now I'm wondering if something with valves?


Possibly? Have you had the valve cover off? If you haven't, it might be worthwhile to pull the cover and check the lifters/cam followers for excessive play.

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3 years 7 months ago #43087 by JKUman
Sorry about that. :blush: KOEO is Key On Engine Off. Digital Multi Meter connected to the battery negative post.

I asked about the voltages on both knock sensor wires because the code suggests that the knock sensor circuit is open. Voltage checks at the knock sensor might prove or disprove that.So black on the DMM to negative battery and the red on DMM to either wire on sensor connector? I'll have to rig up some longer wiring to make this happen, this little booger is right under the intake manifold and very hard to get to.

The fact that you can clear the code and not get it back for a day or so means it isn't a hard fault, and likely isn't a complete open/short in the wiring. Technically I'm only clearing the CEL, the code is permanent.


Possibly? Have you had the valve cover off? If you haven't, it might be worthwhile to pull the cover and check the lifters/cam followers for excessive play.[/quote]10-4, I'll check this coming weekend.

Thanks Tyler for your suggestions.

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3 years 6 months ago #43818 by jeffrey1979
I had the same problem. They wanted $1,200 to fix this and it went away after I did what you said. You are the man!
The following user(s) said Thank You: Noah, Tyler

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