another code 43

[ROSEDOGGYDOG]

First of all I did do a search for the ESC and it was helpful, but I have some questions regarding what I read.

What is "knock"? I'm being honest, I really don't know.

How do I know if it is "knock"?

How can I be sure that it is the ESC and not the EST?

Since "Z" is for sy/ty, I assume that I am to use the other sensor for "W"

http://www.syty.net/phpBB2/viewtopic.php?t=12571&highlight=esc

http://www.syty.net/phpBB2/viewtopic.php?t=8948&highlight=esc

...and here's my story...

My check engine light came on twice this weekend (Friday & Saturday). Both times it came on were after I had driven the truck for awhile then turned off the igintion (picking up son & going to the store), then started it back up.

The first time when I started it, I noticed the light stayed on longer than it should have and I immediately turned it off. When I started it back up (30 sec. later) the light did not come back on.

The second time it came on, I let the truck continue to run and the light went off on its own after about 15 sec.

Both times the truck ran fine afterwards.

So yesterday I used my "GM CODE READER" and I got a code 43.

A code 43 states: Electronic spark timing (EST) circuit - low voltage detected
-or-
Electronic spark control (ESC) - circuit problems.

Great!

 

[doomdead]

knock = detonation = kaboom!... usually when we have high boost/low fuel.

I doubt you have to worry about it on a stock sonoma gt.

Yes I belive your vin is W, go out to your truck, look at dash on the drivers side (from outside the truck). you will see the vin plate. the center letter is a W or Z for us. again your W i belive.

Low voltage.... IMO i would check the wires make sure you have good solid connections from the coil, to the dist, to the plugs.... i think everyone else would agree.

 

[SYO237]

CODE 43
ELECTRONIC SPARK CONTROL (ESC) CIRCUIT
4.3L TURBO (VIN Z) SYCLONE AND TYPHOON (PORT)

Circuit Description:
The knock sensor is used to detect engine detonation and the ECM will retard the electronic spark timing based on the signal being received. The circuitry within the knock sensor causes the ECM 5 volts to be pulled down so that under a no knock condition, CKT 496 would measure about 2.5 volts. The knock sensor produces an A/C signal which rides on the 2.5 volts, DC voltage. The amplitude and signal frequency is dependent upon the knock level. If CKT 496 becomes open or shorted to ground the voltage will either go above 3.5 volts or below 1.5 volts. If either of these conditions are met for about 5 seconds, a Code 43 will be stored.






I have the same problem on the typhoon right now... there are days that I turn on the truck and the check engine will stay on... then go off after a few minutes.

Knock Sensor seems to be the culprit, im changing mine out in the next week or so...


I strongly suggest staying out of WOT with a code 43 until you resolve the problem. No knock sensor...no motor :wink:

 

[InvisiBill]

I assume you understand the basics of how a piston travels in an engine, and when ignition is supposed to take place and stuff. Knock/detonation is when the mixture ignites at the wrong time from something other than the spark plug. Obviously, it's going to be bad if the mixture ignites when the piston is on its way up instead of at the top ready to go back down. A richer mixture and higher octane make the mixture less likely to ignite by something other than the spark plug, which is why race gas and more FP can help knock.

FYI, the ESC is the circuitry covered by the squishy epoxy inside the MEMCAL, next to the PROM chip. Swapping the MEMCAL will thus also be swapping the ESC...

Edit:

http://www.syty.org/old/promguide.html

The MEMCAL is what most people call the "chip". It's the black/brown T-shaped base which plugs into the ECM, the PROM (programmable read only memory) chip that holds the actual software, the ESC circuitry, and the blue cover that snaps over the PROM and ESC.