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Discussion Starter #1
ok i did the rewire for the knock sensors in december. it was running with out that code for a until now. i only get the code in boost it seems like.

my AFC is hooked on to my front knock sensor and it reads that fine (there's a signal coming from the sensor). my PLX r-500 is wired on my rear knock sensor and there's no reading on the plx for that at all (no volts/hertz reading). could it be that my wiring has gone wrong or is my sensor bad? how do i check to see if my sensor is bad.

The code happens even when my AFC is zerod out.

thank you
 

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when this baby hits 88mph
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easy way to check if one of the sensors is bad is to tie the inputs together at the ecu. if the code goes away, most likely a bad sensor. if it doesnt, most likely bad wiring.
 

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Discussion Starter #3
tie them in together? as in cut the one that is causing the problem at the ecu and put it on the other one? The bad sensor not connected (it's own terminal) at the ecu correct ?

thanks
 

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when this baby hits 88mph
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no you still need a signal at both terminals at the ecu. or maybe im confused at what you are saying. either way, the best way is just strip the insulation a few inches back from the ecu plug (the only ones that look like speaker wire) and tie the 2 wires together. you can do this another piece of wire by wrapping each end around each knock wire or use jumper clips. hope this makes sense.
 

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BMM
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| |
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|-|
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| | <-- something like that i think...

parallel=knock sensor wires
horizonal= connecting wire
 

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This Is Why I'm Hot.....
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Rewiring the sensors as suggested sounds like too much work that could potentially result in some very ugly wiring when all is said & done.

My take on Code 52:
1] 9.8 times out of 10 it is faulty wiring.
2] If you want to test the sensor, put a volt/ohm meter on it & tap it lightly, watching for a voltage fluctuation. IIRC, severity of tap can range from .1 to 1.5V, or somewhere thereabouts. Regardless of the actual values, if there is no voltage fluctuation, then the sensor is bad.
3] Buy junkyard knock sensors only [I paid $147 for one ~2 years ago @ local Toyota dealer]
4] If you do rewire, don't use solid core cabling. Use multi-stranded RG56-58, 20 or 22AWG.

Good luck.
 

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Discussion Starter #7
ok i get what your talking about.

i did do the rewire with the multi strand wire in december. it was working fine up until now.

to check voltage, do i tap the sensor or the wire?

thanks
 

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This Is Why I'm Hot.....
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87_targa said:
ok i get what your talking about.

i did do the rewire with the multi strand wire in december. it was working fine up until now.

to check voltage, do i tap the sensor or the wire?

thanks
I had to re-do one of mine, too, but that was due to breaking it while replacing a starter.

As for your question, I didn't say test the wire, I originally wrote:
.....If you want to test the sensor, put a volt/ohm meter on it & tap it lightly,.....
I believe the sentence is grammatically correct.

Good luck.
 

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when this baby hits 88mph
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Larry_A said:
Rewiring the sensors as suggested sounds like too much work that could potentially result in some very ugly wiring when all is said & done.

Good luck.
i understand what you are saying larry. but its quick and easy unlike how complicated i like to make it sound haha. i agree its usually wiring, but this method you would know for sure. however, you wouldnt know which is bad, just that one of them is. sure you can watch the voltage while tapping on the intake manifold but they are kinda hard to get at and test by yourself. you could also run a timing light and tap on the intake manifold and see if timing drops. my theory was you would quickly know what the problem was and like we agree, usually wiring. hopefully he will get it sorted :)
 

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What alot of people suggest is to check to make sure that either the knock sensor did not come loose from the block, or that the plug did not come loose from the sensor.
 

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Discussion Starter #11
i am pretty sure my rear knock sensor is the one causing the porblem, i just don't know if it's the sensor or the wiring. my AFC is wired to my front sensor and reading volts. my wideband is wired to my rear sensor and it doesn't pick up any volts.

ok sorry i was just confused about the tapping and were to put the volt/ohm meter.
 

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Discussion Starter #12
ok i did the tap check on both. the front one jumps around when i tap it. the rear one reads zero. sometimes though, the rear one will get a reading.

bad sensor?? junk yard fix?


thanks
 

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where did you put the ohm/volt meter, if you put it right near the sensor and not after u changed the wire than yes it wud be bad sensor, but if you put it after your splice than again it could be bad wiring. If you did put it after your splice trying wiggling your connection around and see if that helps with signal.
 

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Discussion Starter #14
ok i did that and checked my wiring.

but something wired happened. got 4 codes the other day. two had to do with the airflow meter (temp, and sensor), one was for boost pressure, and then the knock sensor. i disconnected my AFC's airflow wires and reconnected the stock wiring. when that was done, no more code 52 or any other code. what is going on?
 

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Ok I know I see people posting about testing ks with volt meter and im assuming that you need to have it plugged in and key turned on to do such a test?:wtflol:
 
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