knock sensor wire
10-14-2008, 07:09 PM
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knock sensor wire
hello i have a 1989 v6 toyota manual pick up i have been getting a code 52 for a while and i have a miss on my engine the dealer wants 3000 dollars to take care of it. my truck seems to have the knock sensor wire as it comes out of the block cut but not alot will this cause the code or is there any test i could do to it ,with an ohmeter to check i really would not like to tare the engine apart just to find out is not the problem can anyone help ,i would also like to find out if some one has the knock sensor pigtail wire for sale for this truck thanks in advance
10-14-2008, 07:17 PM
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If the wire is cut....yes, that will throw the code. If you want the pigtail, just go to the dealer...I think its 15$ or so, but if going that far, you should get the intake gasket kit as well, you will be pulling the plenum and manifold off.
10-14-2008, 07:26 PM
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Hey, and welcome to YotaTech...
Code 52, as you know, is the knock sensor code. There's a very well known problem with the wiring in that area. The sensor itself is in the middle of the engine, under the intake manifolds. Major pain to get at. It's accepted practice at Toyota that if you have the intake off for any reason, that wire is to be replaced. They get hard, brittle, and break. Poor connections cause false readings, and the ECU throws a code.
Unfortunately, the only way to check the knock sensor is to pull the manifold. You can't test it via the wiring, since it's a VERY likely culprit by itself.
The manifold is not hard to remove, just time consuming. I recommend purchasing a Service Manual (Either Factory or Hayes) and replace the sensor and wire. You're going to invest 6 hours into pulling it apart... you'd be damn pissed afterwards if you didn't replace the sensor at the same time and the code came back.
By the way, the knock sensor uses a single, black wire that goes to Connector B, Pin 17. If you wanted to be VERY good, you can do your wiring repair and then check the resistance between Pin 17 and the Knock sensor connector.
Edit: Sorry Team420... it's late and I'm typing slow. Didn't mean to repeat ya there
Code 52, as you know, is the knock sensor code. There's a very well known problem with the wiring in that area. The sensor itself is in the middle of the engine, under the intake manifolds. Major pain to get at. It's accepted practice at Toyota that if you have the intake off for any reason, that wire is to be replaced. They get hard, brittle, and break. Poor connections cause false readings, and the ECU throws a code.
Unfortunately, the only way to check the knock sensor is to pull the manifold. You can't test it via the wiring, since it's a VERY likely culprit by itself.
The manifold is not hard to remove, just time consuming. I recommend purchasing a Service Manual (Either Factory or Hayes) and replace the sensor and wire. You're going to invest 6 hours into pulling it apart... you'd be damn pissed afterwards if you didn't replace the sensor at the same time and the code came back.
By the way, the knock sensor uses a single, black wire that goes to Connector B, Pin 17. If you wanted to be VERY good, you can do your wiring repair and then check the resistance between Pin 17 and the Knock sensor connector.
Edit: Sorry Team420... it's late and I'm typing slow. Didn't mean to repeat ya there
Last edited by Noltz; 10-14-2008 at 07:28 PM. Reason: I'm slow
10-15-2008, 10:55 AM
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a little test I did to check the ks....I havent been able to confirm this as an accurate way to test it tho. Use a multi meter, just as tho u were testing for continuity, only set the meter to check millivolts... then tap on the side of the block...dont beat it...just tap, and monitor the meter for any changes while tapping, then start the truck, and see what happens to the meter...if nothing happens at all...I would suspect a fualty connection, of knock sensor.
Hope this helps....but as I said...I havent confimed it to be accurate.
Hope this helps....but as I said...I havent confimed it to be accurate.
10-15-2008, 03:15 PM
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A multimeter isn't fast enough to catch tapping a knock sensor. The refresh rate is too slow. Perhaps with a graphing meter like a Vantage, but otherwise no go.
What you could do is use a timing light, watch your ignition point and tap the block. See if the ECU pulls the timing back. Dunno if that'd work either though. Just thinking out loud
What you could do is use a timing light, watch your ignition point and tap the block. See if the ECU pulls the timing back. Dunno if that'd work either though. Just thinking out loud
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04-17-2012, 03:02 PM
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Also, is it true that when knock sensor is working it will retard timing when it picks up a knock and engine light will never come on until there is a problem with the system. or dose engine light come on when knock sensor picks up a knock?
04-17-2012, 04:46 PM
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"With engine speed 2,000 rpm or more
signal from knock sensor is not input to
ECM for 25 revolutions. (KNK)"
So Sayeth the Holy Book: http://www.ncttora.com/fsm/1990-1995...e/diagnosi.pdf
The ignition is advanced until the knock sensor detects knocking, and then it is gently retarded until the knocking stops. If it can't get the SIGNAL, it retards the timing to protect the engine (and ruin your power and mpg), and sets the CEL.
signal from knock sensor is not input to
ECM for 25 revolutions. (KNK)"
So Sayeth the Holy Book: http://www.ncttora.com/fsm/1990-1995...e/diagnosi.pdf
The ignition is advanced until the knock sensor detects knocking, and then it is gently retarded until the knocking stops. If it can't get the SIGNAL, it retards the timing to protect the engine (and ruin your power and mpg), and sets the CEL.
04-21-2012, 08:20 PM
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My head gasket blew so I tore my engine down replaced head gaskets put it all back together and get a 52 code So I have replaced knock sensor, lead, and ecu still have code 52. I would now like to rewire from pig tail to the ecu. can i do this with regular wire? please help.
