Intermitent Code 43..strange
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Junior Member
Joined: Dec 1999
Posts: 16
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From: san diego
Intermitent Code 43..strange
For about two weeks, I have been getting a Code 43. I did the paper clip trick on the Diagnostic link and it came up 43. Today, a very strange thing happened. I was going up hill about 25mph through a construction zone. The SES light came on, I felt the engine stumble, then the weird part. The light went off by itself. Any suggestions? Typically, SES lights do not go off while the car is running. The brown ground wire for the computer is solidly attached. I do not have any diagnostic tools, so I may have to bring the car in to a shop. I live in San Diego, so if any local members are on the board today, let me know where there is a good shop to bring the car into.
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Joined: Jan 2000
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XCLR8,
If you are going to a shop, why bother posting here? Not a criticism, but just asking. Since you've already discovered the stored code, half the work is done. Whay pay someone else to finish the job?
If you are curious about the code, a '43' is for a range of different things on different vehicles. It always helps to post the year/engine/fuel system type with questions like this.
If you have a TPI, the code is for a problem with either the ESC or Detonation Sensor (Knock Sensor).
You can test the Detonation Sensor with a high-current analog ohmmeter and a hammer. Connect the ohmmeter to the sensor output and a ground, then tap the block near the sensor. The magnetic sensor should generate a pulse which the meter should interpret as a sharp drop in resistance (needle swing).
Or you can use a timing light and the hammer. Connect the timing light as usual, then tap the block near the sensor while observing the timing marks. The timing should retard sharply then return slowly to a "normal" range. Unfortunately, this test doesn't differentiate between a bad sensor and ESC, so you'll end up testing or replacing the sensor anyway.
If the sensor proves defective, replace it yourself. Since it threads into the cooling jacket in the case, this would be a good time to flush and refill your cooling system. It can be replaced without draining the system, but is a little messy.
If the sensor tests good, the ESC itself may be failing or you may have failing connections between the ESC, sensor, and ECM. Check the wiring and connectors, and bypass the ESC for a test drive if necessary. You can disconnect the test connector near the heater blower wiring to bypass the system.
If you have absolutely no tools, you can still disconnect the EST bypass connector to confirm your suspicions.
If you have an older ThidrGen with a carburetor, the '43' can mean a TPS sensor out of range. This would not likely be an intermittent error, but would be steady.
------------------
Later,
Vader
------------------
"No matter how hard you try you can't stop us now"
Adobe Acrobat Reader 4.0
If you are going to a shop, why bother posting here? Not a criticism, but just asking. Since you've already discovered the stored code, half the work is done. Whay pay someone else to finish the job?
If you are curious about the code, a '43' is for a range of different things on different vehicles. It always helps to post the year/engine/fuel system type with questions like this.
If you have a TPI, the code is for a problem with either the ESC or Detonation Sensor (Knock Sensor).
You can test the Detonation Sensor with a high-current analog ohmmeter and a hammer. Connect the ohmmeter to the sensor output and a ground, then tap the block near the sensor. The magnetic sensor should generate a pulse which the meter should interpret as a sharp drop in resistance (needle swing).
Or you can use a timing light and the hammer. Connect the timing light as usual, then tap the block near the sensor while observing the timing marks. The timing should retard sharply then return slowly to a "normal" range. Unfortunately, this test doesn't differentiate between a bad sensor and ESC, so you'll end up testing or replacing the sensor anyway.
If the sensor proves defective, replace it yourself. Since it threads into the cooling jacket in the case, this would be a good time to flush and refill your cooling system. It can be replaced without draining the system, but is a little messy.
If the sensor tests good, the ESC itself may be failing or you may have failing connections between the ESC, sensor, and ECM. Check the wiring and connectors, and bypass the ESC for a test drive if necessary. You can disconnect the test connector near the heater blower wiring to bypass the system.
If you have absolutely no tools, you can still disconnect the EST bypass connector to confirm your suspicions.
If you have an older ThidrGen with a carburetor, the '43' can mean a TPS sensor out of range. This would not likely be an intermittent error, but would be steady.
------------------
Later,
Vader
------------------
"No matter how hard you try you can't stop us now"
Adobe Acrobat Reader 4.0
Last edited by Vader; Mar 31, 2018 at 10:28 PM. Reason: Updated links
Thread Starter
Junior Member
Joined: Dec 1999
Posts: 16
Likes: 0
From: san diego
Time is usually a factor in whether or not to bring the car into a shop. Also, as mentioned before, I do not have the specialized tools needed. (except for the timing light) The biggest factor is experience in actually diagnosing problems and fixing them. Thank you for the picture and info. At least I know where to start. This is my only car and if I screw something up on a Saturday afternoon, I am stuck. That is why I posted the question. I now lots of other members have been down this river before and can inform me of practical solutions that I can understand. Boards like this are a much better source of info than alot of manuals. Again, thank you for your reply and I will run the test you suggested later today.
Supreme Member
Joined: Sep 1999
Posts: 3,197
Likes: 10
From: Manassas VA
Car: 04 GTO
Engine: LS1
Transmission: M12 T56
I'm rehashing this cuz i have the same problem and i have an idea i want to run by you guys.
I only get an intermittent SES light on cold starts on really cold mornings (20ish degrees.) Sometimes it happens while i'm still idling/warming up, other times it comes on a couple minutes down the road. No matter what, it will generally go off after 15 seconds to a minute. Sometimes it happens twice in the same morning, sometimes not at all.
Due to the cold and my lack of time i haven't done much to diagnose it. All i've done so far is check the connector at the knock sensor when it was on a lift getting tries. Connection looked good, and the wire looked OK too.
So now what do i do. Tapping the block wile the engine runs and i watch the timing marks seems like a PITA. Would a simpler and more accurate test be to simply replace the knock sensor with a resistor and see if the problem dissappears? If it did then i would know the problem was in the sensor. If not then i would know my ESC/wire was at fault.
Due to it's only happening in frozen conditions i'm leaning towards a bad sensor. The wire and ecm shouldn't work significantly different once warmed up in this sense.
goddamn TPI, actually caring if something is wrong. This is why CCCS will always rule, it only yells at you if something is actually wrong, not cuz of gay intermittent who cares problems.
...ed
edit...an important part of this diagnosis is the fact that it has happened while idling/warming up, so it is not seeing real detonation. Also of note, the engine is quiet, it's not like it's knocking/piston slapping (at least audibly) and setting it off unless it's too sensitive and bad. And even then, if that were the case, why would it not do it on every cold start, and why not always while it's idling/warming up.
[This message has been edited by Ed Maher (edited January 03, 2001).]
I only get an intermittent SES light on cold starts on really cold mornings (20ish degrees.) Sometimes it happens while i'm still idling/warming up, other times it comes on a couple minutes down the road. No matter what, it will generally go off after 15 seconds to a minute. Sometimes it happens twice in the same morning, sometimes not at all.
Due to the cold and my lack of time i haven't done much to diagnose it. All i've done so far is check the connector at the knock sensor when it was on a lift getting tries. Connection looked good, and the wire looked OK too.
So now what do i do. Tapping the block wile the engine runs and i watch the timing marks seems like a PITA. Would a simpler and more accurate test be to simply replace the knock sensor with a resistor and see if the problem dissappears? If it did then i would know the problem was in the sensor. If not then i would know my ESC/wire was at fault.
Due to it's only happening in frozen conditions i'm leaning towards a bad sensor. The wire and ecm shouldn't work significantly different once warmed up in this sense.
goddamn TPI, actually caring if something is wrong. This is why CCCS will always rule, it only yells at you if something is actually wrong, not cuz of gay intermittent who cares problems.
...ed
edit...an important part of this diagnosis is the fact that it has happened while idling/warming up, so it is not seeing real detonation. Also of note, the engine is quiet, it's not like it's knocking/piston slapping (at least audibly) and setting it off unless it's too sensitive and bad. And even then, if that were the case, why would it not do it on every cold start, and why not always while it's idling/warming up.
[This message has been edited by Ed Maher (edited January 03, 2001).]
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