code 43 on cold start
Thread Starter
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
code 43 on cold start
New issue started last night. Temp~30 deg when I started the car after a couple of sec SES came on code 43. Turned it off restarted did the same. Let it run till the engine temp hit 50deg shut down, restarted no SES.
Went out this morning to pull the codes and when started same thing. Shut down restarted no code.
Mobile 1 oil 5W30 Never got a knock sensor code before and did not really hear it although idle was a little rough till it warmed up a bit. Piston Slap? Could injectors sticking cause this?
Went out this morning to pull the codes and when started same thing. Shut down restarted no code.
Mobile 1 oil 5W30 Never got a knock sensor code before and did not really hear it although idle was a little rough till it warmed up a bit. Piston Slap? Could injectors sticking cause this?
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
If you check the diagnostic tree in the book you will see the code does not indicate the sensor is sensing knock rather it means the ECM detects improper voltage on the circuit. That said I will relate my experience with the same code, also on a 93.
Like yours it normally set shortly after a cold start, though I'm sure the temperature here in Florida was no where near 30* when it occurred. I ran the diagnostics using the DVOM, 5 volt supply to both sensors checked good, resistance of both sensors was within specs but each was different, don't recall the exact values. I also checked the wiring from the sensors to the ECM, all seemed fine but since it was intermittent I figured a bad connection was the most likely culprit so I replaced both knock sensor connectors without success.
Finally got annoyed and replaced both sensors, the code has not returned, just my experience, your mileage may vary, good luck.
Like yours it normally set shortly after a cold start, though I'm sure the temperature here in Florida was no where near 30* when it occurred. I ran the diagnostics using the DVOM, 5 volt supply to both sensors checked good, resistance of both sensors was within specs but each was different, don't recall the exact values. I also checked the wiring from the sensors to the ECM, all seemed fine but since it was intermittent I figured a bad connection was the most likely culprit so I replaced both knock sensor connectors without success.
Finally got annoyed and replaced both sensors, the code has not returned, just my experience, your mileage may vary, good luck.
Thread Starter
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
If you check the diagnostic tree in the book you will see the code does not indicate the sensor is sensing knock rather it means the ECM detects improper voltage on the circuit. That said I will relate my experience with the same code, also on a 93.
Like yours it normally set shortly after a cold start, though I'm sure the temperature here in Florida was no where near 30* when it occurred. I ran the diagnostics using the DVOM, 5 volt supply to both sensors checked good, resistance of both sensors was within specs but each was different, don't recall the exact values. I also checked the wiring from the sensors to the ECM, all seemed fine but since it was intermittent I figured a bad connection was the most likely culprit so I replaced both knock sensor connectors without success.
Finally got annoyed and replaced both sensors, the code has not returned, just my experience, your mileage may vary, good luck.
Like yours it normally set shortly after a cold start, though I'm sure the temperature here in Florida was no where near 30* when it occurred. I ran the diagnostics using the DVOM, 5 volt supply to both sensors checked good, resistance of both sensors was within specs but each was different, don't recall the exact values. I also checked the wiring from the sensors to the ECM, all seemed fine but since it was intermittent I figured a bad connection was the most likely culprit so I replaced both knock sensor connectors without success.
Finally got annoyed and replaced both sensors, the code has not returned, just my experience, your mileage may vary, good luck.
Thanks for your reply
I looked at the DTC tree and have not had time yet to go through the diagnostics but I am mighty suspicious at the apearent relationship between the temp and the code. I plan on monitoring it to see if it occurs when the engine temp is not so low it was 25 deg this morning here although I had no issues on my last car in Ohio like this and did ocasionally start it in cold weather.Did yours reset itself or did you have to turn the engine off and restart?
One other question do I have to drain the coolant to replace the KS or can I swap it out quickly?
Last edited by Redeasysport; Dec 8, 2008 at 01:32 PM.
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
Thanks for your reply
I looked at the DTC tree and have not had time yet to go through the diagnostics but I am mighty suspicious at the apearent relationship between the temp and the code. I plan on monitoring it to see if it occurs when the engine temp is not so low it was 25 deg this morning here although I had no issues on my last car in Ohio like this and did ocasionally start it in cold weather.Did yours reset itself or did you have to turn the engine off and restart?
One other question do I have to drain the coolant to replace the KS or can I swap it out quickly?
I looked at the DTC tree and have not had time yet to go through the diagnostics but I am mighty suspicious at the apearent relationship between the temp and the code. I plan on monitoring it to see if it occurs when the engine temp is not so low it was 25 deg this morning here although I had no issues on my last car in Ohio like this and did ocasionally start it in cold weather.Did yours reset itself or did you have to turn the engine off and restart?
One other question do I have to drain the coolant to replace the KS or can I swap it out quickly?
Don't attempt it when hot, you will scald yourself, almost guaranteed.
Let me know if you determine the temperature relationship, it is interesting but not enough to concern myself with once I got rid of the code.
Thread Starter
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Thought I would update it was 17 degrees this morning and I got it again for about 3min so it does indeed seem to be temp related as I had no 43 since my last post. Not gonna worry about it till it does not go off I rarely have temps that low around here.
