3.4l V6 Knock Sensor Code

[kyleh Junior Member Find all posts View Profile Close kyleh]

Anyone had problems with knock sensors on 5VZ?

After car is warm and engine is placed under load, check engine light comes on and car dramatically loses power. Stays like this until car is restarted. Code indicates knock sensors, which explains the lack of power as I imagine the computer plays it safe and retards the timing.

Have replaced sensors, and loom under manifold. Have done basic checks back to ECU, no short or open circuit to sensors.

Apart from this engine is in excellent condition, has had top end rebuild and runs beautifully.

I'm at a total loss as is every person who has looked at the problem.

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

Wow.. that is a complete mystery! The harness is a major problem. Im an auto electronics tech (little different to an autoelec) and I live in the Dandy Ranges. We can probably arrange for me to have a look at it.

When you replaced the loom, how was it done? Was a brand new loom sourced? Was one made up (how I fixed my issue) or was 2nd hand used. If a second hand loom was used there is a very good chance the insulation cracked during installation.

I'll send you a PM with my number if you want to contact me.

[kyleh Junior Member Find all posts View Profile Close kyleh]

Thanks for the reply, much appreciated and will be in touch. For additional information, the replacement steps were as follows:

1. The under manifold loom was replaced originally with a genuine new loom. There was no change.
2. The plug was then cut off new loom and temporary replacement cable wired directly to ECU, bypassing engine loom. No change.
3. Plug was soldered back in to use engine loom and both sensors replaced. Initially seemed to take longer to fail but then same.
4. Manifold was taken off again, sensors checked for tightness, looms checks for continuity, joins checked and re insulated etc. No change.

Cheers,
Kyle

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

Ok. That gives me something to work with.

What codes specifically are being thrown? There are a total of four knock sensor codes that are possible.

12, 13, 52 and 53

12 and 13 are thrown when it detects an issue with the sensors.

52 and 53 are thrown when it can't detect the sensors at all.


The sensors are only active after the engine reaches a load point/ RPM or coolant temp.

until one of those conditions are met, the knock sensors are disregarded.

[kyleh Junior Member Find all posts View Profile Close kyleh]

To be honest I'm not sure which specific codes it is, I haven't seen them myself and haven't been told explicitly. Do you know off the top of your head which pins/connector I need to bridge to flash them out?

I suspected that would be how they would activate and why its not an issue until it warms up.

[Bewitch Lurker Find all posts View Profile Close Bewitch]

Did u find out what was wrong with is because I have had the exact same problem been to handfuls of different mechanics replaced sensors twice and still going been over a yr and still don't know what is wrong

[kyleh Junior Member Find all posts View Profile Close kyleh]

No, haven't fixed it yet, I've kind of gotten used to changing to 2nd to get up hills!

I'm going to pick up a new 3-pin plug and some suitable cable to make up a new lead from the sensors to the ECU. With any luck I'll try that over the weekend and report back.

Kyle

[uneek22 Lurker Find all posts View Profile Close uneek22]

any updates on this? im having a simmilar issue

[Haighie Lurker Find all posts View Profile Close Haighie]

No Fix

any updates on this? im having a simmilar issue

Hi, I have just gone through the trouble of replacing both knock sensors and wiring harness only to find that the engine light (code 52) is still showing and the performance is still less than wonderful. Decided to search forums and found this one, has this problem been solved by anyone, will replacing my ECU fix the issue?

Help please.

[kyleh Junior Member Find all posts View Profile Close kyleh]

Sorry guys, sold car with the existing problem over a year ago. Not sure if new owner managed to fix it or not, I do see it driving around regularly so will try and find out.

Kyle