I replaced the knock sensors in my brothers camaro and its still reading the code? What is there that I could have possibly done wrong? I screwed them in and conected the wire so I dont know why they read low output.

 

did you delete the code after you replaced them?

 

ya the light went off them came back on later in the week, as soon as I went to get it inspected of course.

 

were the sensors new?

 

ya ordered 99^ sensors and the new wire and installed them and the code reads low output on both sensors. (PO 332, PO 327)

 

I fought this for awhile. Went through the Helms manual troubleshooting procedures and I ended up replacing the PCM. It checks the sensitivity of the sensors, continuity between the sensors and the rear harness, continuity between the rear harness and the PCM pins, for grounds, etc.

 

so do you think the pcm is bad?

 

If you have a spare PCM with the correct part number and calibration, you can try swapping it. I wouldn't just buy another one without first confirming the rest of the wiring is OK, though.

 

o ok I dont have a spare but what wiring should I check?

 

Sometimes bad KSs will cause the pins on the PCM to disintegrate. This happened to me. I needed to replace the PCM.

 

Paraphrased from my 99 Helms manual:

1. Disconnect the knock sensor electrical connector located behind the intake manifold. Measure the resistance between the appropriate knock sensor signal sircuit (sensor side of harness) and battery ground using a DMM. Set the DMM to the 400K ohm scale. Resistance should be between 93-107 K ohm. If OK, goto step 2. If not OK, goto step 4.

2. Connect the DMM between the appropriate knock sensor signal circuit and the engine block. Set the DMM to the AC voltage scale. Tap on the engine near the appropriate sensor while observing the DMM reading. Do you receive minor voltage spikes when tapping which quickly return to zero? If yes, this is normal, and goto step 3. If no, goto step 5.

3. Disconnect the PCM connector which contains the knock sensor pins. I remember the pins being different between my 98 vehicle and my 99 Helms manual, but I don't recall if the connectors were different also. Make sure you find the correct connector and pins for the appropriate vehicle. Using the DMM, test the circuit between the PCM and the knock sensor connector for an open, a short to voltage and/or a short to ground. Repair as necessary and re-test for the symptoms. If symptoms still recurring, goto step 6.

4. With the intake manifold off, test for an open or a short to ground in the signal circuit between the knock sensor jumper harness connector at the back of the intake manifold and the knock sensor connector. Repair as necessary. Re-test. If still recurring, goto step 5.

5. Replace the knock sensor(s). and re-test for symptoms.

6. Inspect for poor connection at PCM, and repair as necessary. Re-test for symptoms, if symptoms recur, goto step 7.

7. Replace the PCM, Make sure you reprogram it. Re-test for symptoms.

8. [End of diagnostic]

 

False knock?

 

The codes are a result of a hardware failure. False knock won't set the codes, but will be generated as a result of the codes/failure. If you're getting KR without the codes, then you can troubleshoot the possibility of false knock.

Before working on the diagnostic, I put in a full tank of unleaded 104 and the false KR failed to go away. I also desensitized my knock sensor tables as far as they would go (without disabling KR) and the false KR remained. Setting max KR to 0 was the only way I found to work around it in the PCM, but I won't turn off my knock sensors.