1989ToyotaStake

Guys, I am new to the forum, lots of great info out there. Thanks for all you guys share. I have a 1989 Pickup with the V6 engine. Getting the dreaded code 52. I ordered a new pigtail and sensor. But with reading here, I figured it might be best to see if the wire was the issue. So, I located the juncture of the pigtail and the wiring harness and pull it apart. I discovered there was one white wire in the harness that ran to the connector. The connector however looks like it handles 2 wires (possibly the ground??). I noted inside the connector there seemed to be a few strands of wire left but no obvious 2nd wire anywhere floating around the engine. Is this a single wire connector with an extra space for a second that is not used or are there really 2 wires. If there are 2 wires, where would the 2nd go? Thanks!

scope103

While I have never taken this connector apart, the schematic shows the knock sensor lead (and pigtail) to be shielded. A shielded wire (unless cut) should look like a single (slightly fatter) wire. The shield (fine strands) would be brought out to the second pin of the connector (in both directions).

The shield is connected to ground at the ECM, but not at the knock sensor. Probably to prevent "ground loops."

1989ToyotaStake

Thanks for the quick answer. I understand just could not find a wiring diagram to show that. I will ignore the second lead in the connector as it has no wire on it anyway. I did notice that there is crack in the shielding of the wire in the harness (not the pigtail to the sensor). Do you think this could cause it to have a bad read? I will tape it up good and see if it makes any difference. Thanks again for the help.