Codes p0651 and p0449

Good afternoon,

The 651 could either be the AC pressure sensor, if the AC does not work or a failed PCM.

Does the engine run normally?

The 449 is a vent valve in the back of the truck. I posted pictures and a procedure.

Roy


P0651
Descriptor
Probable Causes
Air Conditioning (A/C) Pressure Sensor
Fuel Tank Pressure (FTP) Sensor
Powertrain Control Module (PCM)

P0449
Descriptor
Probable Causes
Evaporative Canister Vent Solenoid
Powertrain Control Module (PCM)

REMOVAL PROCEDURE


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1. Raise and suitably support the vehicle. Refer to Vehicle Lifting.
2. Disconnect the evaporative emission (EVAP) canister vent valve electrical connector (1).


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3. Remove the EVAP canister vent valve bracket bolt.
4. Remove the EVAP pipe from the clips (1).
5. Disconnect the EVAP vent pipe (4) from the EVAP canister.
6. Remove the EVAP canister vent valve and pipe from the vehicle.
7. If necessary, disconnect the EVAP vent pipe (3) from the EVAP canister vent valve (2).
8. If necessary, detach the EVAP canister vent valve (2) from the bracket.

At this point I have found the throttle position sensor wiring. signal wire is shorted to 12 volts. what I need is pin out of PCM. this is my second attempt to reply not sure if it went through the first time.

Cannot have 12 volts. It is a 5 volt sensor. can you retest.

Do you have a actuator motor on the throttle body

Roy

An engine management wiring diagram would be helpful. also, with this I am sure I could ring out wires and bypass this short, with this and pin out of PCM. thanks

Roy, my reading is correct this is problem: Circuit two is shorted out to positive 12 volts this is my problem. ,if you could please send me a pin out of the PCM I could ring out the wires and bypass where it is shorting out at. I know what to do I just need the pin out.

Here are the pin outs for the PCM.

Roy

Thanks, now if you could send me the wiring diagram of the engine management system hopefully I’ll have enough to go on to bypass the wires to the necessary sensors according to info I pulled up trouble codes. net circuit 2 is serving the following sensors ,accelerator petal sensor #1,throttle position sensor #1 and 2 and crank sensor. could you please take a look at the engine diagram to see if this would give me the diagrams I need to follow through from these sensors to
PCM. thanks for all your help.

Wiring diagram attached.

Roy

Roy you're the greatest. really appreciate all your help . told my friends in our Corvette Club, they were impressed. thanks again

You are welcome.

Always glad to help.

Roy

Could you send as separate pages as pdf I could print? thanks

I sent you the pin out of the PCM that had pin numbers and wire colors.

They are ready to print.

What exactly do you need for the rest?

Roy

The last diagrams you sent where what I needed, but I could not make the font large enough when I printed it out. could you maybe brake it down into 2 pages as pdf and let’s see if that works? my wife struggled with it and had no luck. thanks

Okay, I enlarged the diagrams and attached them.

Roy