Code 43

[Subfixer]

After 1200 miles to and around Carlisle and back, the Z ran flawlessly.
Took it to work this morning and the SES light came on after 55 miles. Did some running around and the light came on as soon as the car got into closed loop.
Drove home with the light on, and about 35 miles from work, the SES light went out. Pulled codes and got 43 (saved code), knock sensor. Drove around some more this evening and no codes popped up.
I'll put the car in the air tomorrow and check the connection. Hope that's all it is.

[secondchance]

About 3 years ago, I had my car on a lift at Jim Voter’s garage. Probably changed oil and whatever service while on the lift. Just visual inspection before bring the car down and noticed knock sensor wire had been completely severed. What was interesting was the car ran fine despite O2 sensor being totally disabled and no SES light! Go figure... :icon_scra

[Subfixer]

Still can't find the reason for my code 43. Did all the checks in the FSM.
Knock sensor resistance is in spec.
Have correct voltage at the knock sensor connector.
Reseated the PROM.
Code 43 is still intermittent.
Typical symptom: drive about 60 miles, stop to get gas, SES light comes on as soon as I restart. Car runs fine, no other symptoms except secondaries won't work while light is on.
If the car sits for a few hours, upon restart, SES light is out and car runs normally.
Any ideas of where to check further?

[A26B]

I had exactly the same symptoms. Went through all the same steps, including replacement of the harness connector. It's an intermittent knock sensor failure.

Replaced & problem solved

[Subfixer]

Thanks Jerry. Just ordered one.

[Subfixer]

Probably the easiest repair I've done to date. Knock Sensor screws into a blind hole in the block. I thought it may have screwed into the water jacket, but it does not.
Will find out tomorrow if my intermittent code 43 is gone.

Next up, removing the radio and receiver from the dashboard. Not looking forward to that job......

[QB93Z]

Next up, removing the radio and receiver from the dashboard. Not looking forward to that job......

Start with the Center Console lid (4 screws on the hinge), then work your way forward. One of the three screws for the shifter bezel is under the forward cup holder. Remove the center, upper AC difuser and then you can get to the radio bezel screws. Keep the screws separated, some are machine screws, some thread into plastic.

Jim

[Subfixer]

After replacing the knock sensor, all was ok for a couple of weeks. Last weekend the SES light came on after the car was warmed up. I could hear some part throttle detonation, then the light came on. Code 43 again.

[Subfixer]

Well, I'm getting nowhere with this problem. Still get intermittent code 43.
New Knock sensor, all checks in the FSM are good.
I removed Mark H's chip, but nothing changed. Put it back in.
No vacuum leaks, no other codes stored. Good fuel pressure.
Car runs great even with the SES light on. Just no secondaries when that happens.

Not sure where to look next.

[G8nightman]

Your chip might be bad. The knock sensor electronics are on it. I had the same problem with mine.


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[XfireZ51]

And u’ve checked for continuity between the harness connector and the ECM?
Separate the harness connector from the clip to see if there’s any corrosion?
Same on the ECM side?

[Subfixer]

And u’ve checked for continuity between the harness connector and the ECM?
Separate the harness connector from the clip to see if there’s any corrosion?
Same on the ECM side?



Correct voltage from the ECM at the knock sensor connector. No corrosion.
ECM connections clean.
Sometimes, the car will run all day without any issues.
Other days, I'll get a code 43 as soon as it goes into closed loop, although the code is coming up more frequently than in the past.
I know the car is 27 years old, but it only has 23K miles on it and was garage kept the entire time.

[Hib Halverson]

Just curious...how can you say it's "running" great with no secondaries. Back when I had Barney, if I was driving around with inoperative secondaries, I'd be saying, "This car runs like crap."
:)

Ok...so we know it's not a problem with Haibeck's cal as the OP swapped out the chips and there was no change. We know it's not the sensor because that's been changed.

Does the sensor installed have "plumber's tape" or anti-seize lubricant on the threads? If so, remove the sensor, clean the threads on the sensor and in the block, reinstall the sensor and road test.

If that doesn't solve the issue, do the diagnosis procedures in the Service Manual. You will need a scan tester which supports the LT5 to run that diagnostic.

[Subfixer]

Just curious...how can you say it's "running" great with no secondaries. Back when I had Barney, if I was driving around with inoperative secondaries, I'd be saying, "This car runs like crap."
:)

….. do the diagnosis procedures in the Service Manual. You will need a scan tester which supports the LT5 to run that diagnostic.


If you mean it falls flat at 4000 rpm, then yes, it runs like crap.


I've got the TunerPro RT program to do some data logging, I just have to figure out how to use it.