Code 51 and some ground questions.

[Supra_Villan]

I have a few questions here. I'm having some internal issues with my car right now that i plan to diagnose this weekend sometime. But i also had some other questions i needed answered. I have a code 51
51 Switch Signal


Diagnosis

* No "IDL" signal, "NSW" signal or "A/C" signal to ECU, during diagnosis check.

Trouble Area

* A/C switch circuit
* A/C switch
* A/C amplifier
* Throttle position sensor circuit
* Throttle position sensor
* ECU
I do own a tsrm and i am aware of the online manual , but will the code 51 affect the way the car runs? I have a brand new tps that is freshly calibrated within spec so i think i can eliminate that possibility. The ac on my car is removed and the plugs for the ac are just hanging for now. I do not want ac in my car because when i got it the compressor was broken and the lines were damaged. Its a creature comfort i can spare. So what do i do to get rid of the code 51?

My second question came to me when overlooking a wiring diagram, i was unaware that our cars have 2 battery grounds. I only have one going to the firewall. Where should the other ground go to on the motor? what gauge wire should i use to install one? I also have a ground installed from the rear engine hoist to the firewall, its not a factory looking wire so i'm just making sure its supposed to be there.

 

[martin p]

The ground wire will not affect anything, it may help with grounding on your car, I have fitted a aftermarket grounding kit on mine, and have very low resistance figures at all ground pionts in the engine bay.

The second grounding point is near the starter motor its a thick black cable, it runs down towards the starter motor with the main power cable.

Code 51 is a real time code, Does the car run ok normally?

 

[Supra_Villan]

i have a pesky afm code that wont leave. So thats affecting the way the car runs, and this is the first time i've ran the car since the rebuild so.

 

[jdub]

Code 51 will not affect how the car runs at speed, but it will affect how the motor idles.
Most likely the TPS is not adjusted correctly.

 

[Fubar231]

Code 51 will not affect how the car runs at speed, but it will affect how the motor idles.
Most likely the TPS is not adjusted correctly.

Its most likely the tps, mine was going off but i fixed it last week. It was at like 1340 ohms and it needs to be under 1200.

 

[Supra_Villan]

its a brand new tps and its freshly calibrated i highly doubt it. but i'll double check, thanks for the replies so far guys.

 

[jdub]

A code 51 will appear if the AC is on, and it does not have to be installed
(i.e. is your AC button pressed on?)

Depressing the gas pedal will cause it too...code 51 is a real time code.

What exactly do you mean by "calibrated"?

 

[Supra_Villan]

adjusted within spec according to the tsrm.