I keep getting a code 12 on my pickup. This DTC definition is for the knock sensor. I have a hesitation off idle or when the throttle is snapped wide open in neutral or in any manual gear. This is most noticable at light throttle / cracked to less than 1/4 opened. At WOT or 1/2 + it has full power. Timing is at 5 degrees with the connector shorted, tps replaced with a new Denso unit and has been set multiple times with a feeler gauge, the knock sensor has been swapped and the coaxial cable to it from the ecm has been replaced with the ground being repaired. With a timing light connected and the ecu in timing mode at 2-2500 rpm the timing intermittently jumps from 40 degress to near zero momentarily then back again? An new coil, tune up components, fuel filter have been installed. The EGR main vacuum supply has been plugged with a screw to test if this was the issue but now change exists. I am stuck any ideas?
Thanks
David

85 toy pickup 2.4 fi code 12 issue

 

This ecu is offered only for this year, any ideas as I do not want to replace this without knowing it is defective?

Thanks in advance

David

 

Any ideas for a code 12 on a 1985 toyota pickup with a 22re 4wd.

 

How do spark plugs look? Did you check distributor cap and wires? I have heard water leaks onto computer or fuse block can do strange things.

Can you try swapping in a good knock sensor and computer from a buddy or something? I have used 87 computer on my 85. Think a year or two newer still works as well??? My mitchells manual lists the hesitation problem as a TSB for engine wiring harness upgrade. Not sure which part of harness or what problem is. I have a 87 22re that has the hesitation as well. ( no codes though)