Code 43 93 4.3

[HanktheHound]

My 93 S-10 4.3 Z, has recently started to throw a SES light right after startup, usually when its colder. It only stays on for about a mile or so, then shuts off. I read the code, and its a code 43 E.S.C., now that i know what the code is I still am completely clueless as to what is causing it. Can anyone point me in the right direction as to what may be going wrong with it. The truck runs fine, but I think that my mpg are dropping significantly. Any help will be greatly appreciated.

Dennis

[dmbrisket 51]

sorry i am of no help, but esc codes can be a bitch to find, when my cousin planted a 93 4.3 into his dime, we got a code 17 (i think) and 43, both were a bitch to find and get out, ill ask him to see what his was i remember it was somthing small and stupid setting it off

[blazee]

CODE 43

Trouble Code 43 indicates that there may be a malfunction in the Electronic Spark Control (ESC) circuit. ESC is used to sense spark knock (pinging) and retard the timing to eliminate it. The ECM will retard the timing by as much as 20 degrees in 1 degree increments. A loss of knock sensor signal or loss of ground at the ESC module will cause the signal at the ECM to remain high. The ECM will act as if no knock is present, and may possibly result in engine damage, due to detonation.

Code 43 is set when:

* Voltage at Knock Sensor is above 4.8 volts or below .64 volts.
* Either condition is met for about 10 seconds.

Possible causes:

1) Open or shorted knock sensor

2) Loose knock sensor

3) Excessive mechanical noise within engine

4) Improper or incorrectly installed MEM-CAL in the ECM or defective ECM

5) Intermittent open in the EST line to the ignition module

[98Z]

Sorry to grag up an old thread, but I'm having the same problems with my '93 4.3 Vortec as Hank was having. I'm hoping that Hank got his problems all figured out.

At any rate, I know nothing about the locations of the knock sensors so I thought I'd see if someone on here could tell me where I might find them? The guy at the parts store tells me there is one on the back of the engine and one on one of the sides. Can someone be a bit more specific? And tell me what it is I'm looking for? Is the one on the back of the engine only replaceable if I separate the engine/tranny or is it accessable?

I'd like to check to see if they are either loose or bad connections before I spend money and time to replace them.

Thanks in adavance.

Dave

[dmbrisket 51]

they are a single wire sencer drilled right into the bottum end just above the oil pan (less then half way up to the heads) one end threads into the water jacket and what you see is an inch around by 7/8'' thick piece of metal, go to the parts store and ask to see one, or do an internet search for what they look like