Toyota Repair Problems? Ask a Mechanic for Answers ASAP
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engine vibration will cause knock sensor to send signal.
check engine mounts, exhaust, any unusual noise or detonating noise from regular fuel.
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WRONG!! These codes will not set by excessive engine vibration or knock! They are designed to detect such things and adjust the timing accordingly. These codes mean there is no signal input when the engine speed reaches 2,000 to 5,600 rpm. This can only be caused by shorts or opens in the harness, sensors and so on. If you have the proper test equipment I can assist you further.
Scope is ideal but do you have an ohmmeter and good understanding of how to use it? Do you have a wiring diagram? Where did you get the sensors from? Some history on the car leading up to this problem?
Glad to hear it is the Toyota sub harness. Sad to hear the Auto Zone sensors have had issues with these aftermarket ones and due to the pain in the arss in getting to them I never us anything but Toyota ones. This being said you need to rule out issues with the harness from the connector at the sub harness back to the computer. These input wires from the sensors are ground shielded. On some rare occasions I have seen the shielding short to the signal wire when hot. I have never seen an ECU go bad for these probably nothing wrong with yours. To rule out any issues with the harness what I have done is made a sub harness using shielded wire from radio shack and go from the connector to the ECU and clip the 2 input wires at the ecu, far enough back so you can reconnect the wires with soldier. I take the pins out but you are not going to have the tool to remove the locks on the connector. Run the wire into the computer and drive for awhile to see if there is a problem if the light comes on then this only leaves the sensors as the problem. The second check or test is to disconnect the the connectors at the computer and at the sub harness and ohm test the center signal wire to ground there should be no resistance to ground of any kind. This is not a guarantee because if the problem is intermittent or heat sensitive it may not show up unless you have a mega ohm tester. Let me know what you find.