Finished installing a rebuilt 3vz and now I get code 52; some problem with the knock sensor circuit. When I moved everything to the new block, I replaced the sensor and the pig-tail. Seemed pretty straight forward. I've checked continuity of the harness wire (from the pig-tail to the ECU) and it looks good. So.. can I test this sensor without having to pull the whole intake manifold? If I understand the schematic, one lead in the pig-tail is the output of the sensor, in mV AC. The other is just a shielded jacket to protect the signal. So neither of these should be shorted to ground, yes? And there should be no measurable output from the sensor, unless it senses a ping at around 7Khz. So, if I hit the block with a hammer, should the sensor detect that and give me a signal, or is it unlikely to excite the 7kHz frequency range?