Knock Code on 2000 Camry

The check engine light came on the other day and i took it in to see what was wrong. They ran a diagnostic test and said that the Knock sensor was malfunctioning. He said i had to replace the knock sensor which would cost about $250.

I'm a little concerned about this because shouldn't they have atleast tested the sensor to check resistence? what if the sensor is fine and there really is a "knocking" problem? I realise that it may be difficult to check the sensor but my car is a

4 cylinder and from what i'm told it appears it is easy to get at.

i don't know a lot about cars but simply replacing a sensor that shows a malfunction doesn't really seem like a solution.

Any ideas?

Reply to
hassnein
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When you say "they ran a diagnostic test," who is "they?" An OBD II code scanner will identify which component and related circuit should be checked, such as the knock sensor.

Knock sensors are not tested by checking resistance. The easiest way to check a knock sensor is to artificially induce a knock and see if the sensor puts out a signal. The easiest way to artificially induce a knock is to lightly tap on the engine block right next to the sensor. Knock sensors are very reliable and rarely fail.

A knock sensor contains a piezo-electric crystal, which will produce a spark when hit or twisted. If the engine begins to knock, the knock sensor will send a spark to the computer.

If the sensor is fine and the engine is really knocking, it would should like marbles in a can being rattled.

Reply to
Ray O

Thanks for the response. I took it into my local Toyota dealership and the service advisor said (after charging me $90 for the scan) that the scan shows a "knock sensor" code but they "claim" they checked everything and its all fine so therefore he felt that the knock sensor is gone and i should get a new one. I'm not sure if he did any of the testing you listed but i'm not hearing anything wrong with my engine so i don't know what to do. He made it sound like just get a new sensor and the problem will be solved. Surely there must be some kind of testing to make sure the sensor itself is working or not before making such a recommendation.

Maybe i should take it to another mechanic to see whats wrong. THe last thing i want to do is put in a new sensor and have the light go off again.

Reply to
ajay_987654

If the warranty has expired on the car, I would wait to see if the check engine light comes back on. Unfortunately, the I don't think the knock sensor is not covered by the emissions warranty (check your warranty book to confirm). If the check engine light comes back on, take it to a place that will let you use the OBD II code scanner for free like AutoZone and check the codes. If the code is the same one as noted on the repair order from the dealership, then go to the dealership and purchase the part from the parts department and replace it yourself. Replacing the sensor involves unplugging a wire from it, unscrewing the sensor from the engine block, and reversing the process.

Good luck!

Reply to
Ray O

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