P0121 p0171 p174 p303 high pitched engine whine

As I was driving the VX down the the for sale lot I noticed this high pitch whine all the sudden. Sounds like a belt slipping or a shot bearing. Louder under the engine near the transfer case but I could be wrong about its origin. If anyone wants to buy this truck from me, I'll let it go cheap. How cheap? Bought for 6000 and I have another thousand in but I'll let it go for 5. Also, any troubleshooting on the sound would be greatly appreciated. Car lives in Hell paso. It's listed for sale on this page and planet Isuzu

None of those codes are anything to be worried about....really.

P0121 - Throttle Position Sensor/Switch A Circuit Range/Performance Problem: http://www.obd-codes.com/p0121

P0171 - System Too Lean (Bank 1): http://www.obd-codes.com/p0171

P0174 - System Too Lean (Bank 2): http://www.obd-codes.com/p0174

P0303 - Cylinder 3 Misfire Detected: http://www.obd-codes.com/p0303

All of that could be caused by a bad Throttle Position Sensor. They aren't terribly expensive (quick internet search shows $40 to $150 depending on which one our engine uses) and it's fairly easy to get to to change out.

The high pitched whine may be totally unrelated to the above problems and just happened to show up when everything else went on the fritz. Hard to diagnose the location of the sound with the description you gave. Can you upload a video?

Excellent help. Thank you. I'm gonna get a new TPS tomorrow. I want to upload a video but I haven't a clue how. I also forgot to mention, when all this went down the AC quit working.

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Originally Posted by Vinnybin

Excellent help. Thank you. I'm gonna get a new TPS tomorrow. I want to upload a video but I haven't a clue how. I also forgot to mention, when all this went down the AC quit working.

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The high pitched whine sounds like something in the serpentine belt drive, which would directly affect your A/C compressor. I had an belt tensioner bearing go bad, and it made lots of noises. Easy to replace both the tensioner and the idler. Remove the belt to verify that is where the whine is coming from. Could be the A/C compressor, tensioner, or idler.

Vinny, that IS helpful information. Like Gregg said, maybe remove the serpentine belt and let the VX run for a few seconds to see if the whining goes away. If the AC quit working then it could definitely be something to do with the AC compressor or anything else that the serpentine belt runs. If one of the pulleys froze then the belt might have stopped turning (thus not turning the AC compressor), but the engine would still be spinning making the loud squeal that you heard as the crank pulley still spins and squeals against the stationary belt. OR, if the AC compressor (or compressor pulley bearing) froze then the pulley would be stationary (and the AC not working) and the spinning belt would squeal as it rubbed over the frozen pulley.

You may not need the throttle position sensor as the high idle might be due to the engine trying to compensate for the drag on the serpentine belt if something is frozen.

For The Past 9 Months I Had A High Pitch Whine When I Started The VX Cold Engine. It Would Stop After The Engine Warmed Up. I Tried Everything, Different Belts, Pulleys, Everything & Nothing Worked. The Noise Eventually Grew Louder. My VX Has 115,000 Miles. I Finally Changed The Crankshaft Pulley/Harmonic Balancer On The Bottom of The Engine & Like Magic That Annoying Noise Stopped & NEVER Returned !

Mine is doing this exact same thing. ..associated with the AC compressor. ..not a big deal, I just haven't taken the time to fix it.
...it IS, however, getting quite annoying...