I tripped a code 43 in the 91 GTA 5.7 TPI

New knock sensors installed
New pigtail installed (old was fried)

Still get the code after clearing

Haynes manual says the knock sensor gets a continuous 8-10 volt current

Running test got a range of .15-.3 on the multimeter

Haynes also suggests a possible defective ESC module
I cant find any such module in the engine bay nor a 4 pin plug dangling about

My 92 TBI has the module in place on the firewall where it should be



Any ideers?

 

the Haynes manual is wrong on the voltage to the knock sensor, it gets 5 volts.
on your 91 5.7 TPI, there isn't a ESC module under the hood, its part of the ECM.

unplug the knock sensor & with the key on engine off, check the voltage at the knock sensor connector, any thing other than 4~6 volts is a problem.
if the voltage checks good, with the sensor still unplugged check the resistance of the knock sensor, go from the center contact of the knock sensor to the engine block, it should be around 3.9k ohms, specs call for between 3300~4500 ohms.

 

I have 12.2v at the wire and 4,300 ohms sensor with ign to run, car is not running like previous test

Yeah theres the problem

Any ideas?

 

I kept getting a code 43, voltage and everything checked out, all the wires and plugs were good.

Even swapped out a different ECM (computer) and the chip, and the code still popped up! (Thats something to try, if you have another 3rd gen handy.)

We finally found that there wasn't good contact in the sensor plug end. (The prongs?)

edit: oh, I see you're getting something different with the voltage

 

I disconnected the ECM and retested

Still got a 12V

Im pretty sure i have a short

 

make sure you have the right connector, the cooling fan switch is in the head right above the knock sensor & both connectors are the same. the knock sensor wire should be dark blue, the fan switch shows to be a black wire, although i have seen some that are gray.
the cooling fan switch wire would show around 12 volts key on.

 

Actually that was the problem



Ive only had this car a few weeks and never would have thought the last owner would screw THAT up

 

sure thing