93, S10 Blazer Tahoe, vin, W. 4.3..CPI
The book says "Knock sensor" the scanner says "spark control" The first time it came on while I was driving. I went home and reset it. But it still comes on just by turning the switch on, without turning the motor. Any ideas?
Thanks in advance.

 

Isn't it supposed to do that? My Bravada and Alero both light the SES light when I turn the key before trying to start. While both of mine are obd2, my old truck, a 93 Cheyenne c1500 (4.3tbi) was obd1. That truck would turn on the SES light before starting, too.
As far as the difference in code meaning, I'm not sure. It could be the knock sensor, or the spark control module.


Does it run rough or weird when the light comes on?

 

I'm sorry, I didn't make that very clear. It sets the code (43) just by turning the switch on. Doesn't need to be running to set the code. It starts and runs fine. No miss, lag, or any indication that anything is wrong.

 

Same truck as you... our engines have 2 knock sensors. One is a little harder to get to, I think its around by the back of the intake manifold. The other one is more towards the spark plug part of the block, IIRC.

Did it just all of a sudden start doing this? And it blinks out 4 then 3 when you put the wire in to read the codes?

 

Thanks for the reply. Yep, just driving along, running fine. The SE light came on, I turned around and went back home, read the code, 43. Pulled the battery cable for a few minutes. Turned the key on to see if it had reset. Still got 43. It either didn't reset, OR set again as soon as I turned the switch on. I didn't start the car. It set the code just by turning the key on. I also read it on my scanner. It said "Electronic spark control".

 

Could be the you pulled power "for a few minutes." My truck has sat for MONTHS without power and starts with no codes, now to make it RUN with no codes...

Try longer.

 

lol, yeah that's the trick. Thanks.

 

i have a 93 also and for whatever reason my knock sensor is insanely close to the steering shaft and i keep hitting it and breaking the pig tail end on it. this truck is a off road only truck so as you can imagine everything is mangled and destroyed. anyways just pop your hood and look for a one wire sensor right in the middle of the engine block on the driver side. see if the plug is busted or just fell out.

funny thing is i really dont even notice a difference when its plugged it or not it just shuts the check engine light off

 

Thanks loads. I'll check that first thing in the morning. Yeah I didn't notice a bit of difference in how it ran after the SE light came on.

 

Mr. abig84. I want to thank you from the deepest depths. you hit it exactly right. The plug is busted, wire just hanging..Can you tell be if I can buy the plug or not?


I found it at the local parts store. Thanks loads.