dtc 43 help

[miller09]

ok so I just got my car running and I am getting code 43 knock sensor circuit. its a 94 obd1 computer. I tested the sensor and it has a good ground. ohm checks at 3800 which what I have read is good. checked power at plug with key on I am getting 5 volts which is also good. I have tried 2 pcms with the same problem. so what should I check next? not sure what to do now. can a knock module go bad and set code 43? I used the same lt4 module in both pcms. any help would be great. thanks

[miller09]

hmm I think it just struck me since the lt4 was obd2 should I be using an obd2 knock sensor? if the lt4 km is from a vette is it looking for 2 knock sensors? anyone running an lt4 km in an obd1 single sensor car? let me know what you guys think thanks

[Injuneer]

A 94 PCM needs a 3,800 ohm knock sensor. I ran the LT4KM in my 94, and had no problems with codes. And I ran a real time Scanmaster LT1, which would have shown a code immediately.

You need to see if the knock sensor is grounded properly. While you have 5V on the single wire (I assume you measured that across a block ground, with the harness OFF the sensor), and 3,800 ohms on the sensor, with the harness wire on the sensor, you need to measure voltage between the single pin on the KS and the block. Should get ~2.5V. Anything outside the limits of 0.78 - 4.1V will set the code.

[miller09]

ok thanks I will try that next. I did switch to an lt1 fbody knock module with no change so that's not the problem as you already know. the pcm is from a caprice the car is a 97 I switch to obd1.

[miller09]

ok checking from the pin and the block I am getting 2.4v but still have code 43

[Injuneer]

Did you clear the code?

[miller09]

yup cleared it a couple times. not sure if its related or not but also getting code 23 vss circuit. but more concerned with the knock sensor at this point