Code 51 AC signal on; IDL switch open (part of the TPS). This code will only appear if the IDL switch is open (ie: you're stepping on the throttle in diag mode or the TPS is not properly calibrated) or the A/C system is on or says it is. When the cause of the code is corrected it will automatically remove itself, no need to reset the ECU.

There's nothing amazing about these codes being present. Check electrical connections and wiring and then refer to the TSRM for data on how to test the sensors.

i will check my TPS once i get the multimeter....

curious what makes the few clicking sounds right after stall? is that the TPS? seems to be coming from the throttle area.


ty for help btw...

The only thing that ticks after the engine is turned off is the ISCV while the ECU parks it.

Just found some info here on the forum that suggests that a ISCV thats clicking is working properly...so thats good, one less thing to purchase. It seems the throttle stop screw has been tampered with..i adjusted it and im not stalling anymore....now check engine light comes on when i let OFF the throttle and goes away when ON the throttle. Ill check what codes are present after work.


Ty cre

Tampered with how? How did you adjust it? Why do people always fuck with that. It never moves from its factory preset unless it's messed with.

The computer controls idle via the ISCV, it's plenty possible that the ISCV or it's airways are clogged too.

Check for diagnostic codes.

i think it was tampered because there was yellow paint mark on the screw and it was not aligned.. only code im getting now is a code 31.. the code 51 is no longer present.

Ok, well, test the AFM and inspect it's wiring and connectors. Make sure the TPS is properly calibrated.