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P0122 - Nothing is fixing it!

Old 05-20-2018, 05:21 PM
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Default P0122 - Nothing is fixing it!

I've had P0122 (TPS low voltage) for the longest time, I've gone nuts trying to fix it.
I initially popped the code and nothing seemed wrong, so I left it.
Over time, the car started to idle low or stall, run choppy, and buck badly.
Replaced the OEM sensor with the Omni sensor. No change.
I noticed last week that wiggling the connector made the car stumble, and the TPS % would bounce around on an OBD scanner. So I ordered up a new connector and laid it in (unsoldered). It persists.
I just had a multimeter hooked up to it. With the engine off, power is a rock-solid 5.00 volts to the connector. With the engine on, it's 4.93 to 4.98 volts. Again, very solid reading.
I adjusted the TPS sensor to where it's almost exactly 4.50 volts reference at WOT with the engine off. Reference voltage with the engine off is around 0.42 volts.
With the engine running though, it bounces around. Wiggling the connector, even though it's brand new, and fits snug over the Omni sensor, still makes it stumble. Cleaned the grounds in the engine bay, no change.
It's still awful to drive, and if you watch the video I attached, voltage actually *drops* on a small throttle blip. It can't stay steady.
Idle relearn doesn't do anything. It has another code for P0410 (vacuum pump on all the time, probably sticking relay).
What the heck is wrong?

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Old 05-20-2018, 05:27 PM
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If you tap the connector, can you make the idle stumble? Does sound like a connector issue.
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Old 05-20-2018, 05:31 PM
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Originally Posted by windhund116 View Post
If you tap the connector, can you make the idle stumble? Does sound like a connector issue.
Yes, wiggling the connector at the sensor itself will make it stumble. Wiggling the wire near the fuel rail doesn't really do anything. Replacing the connector and the sensor didn't fix anything though, I don't understand it.
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Old 05-20-2018, 07:40 PM
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I could. Has anyone ever had a faulty Omni sensor like this?
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Old 05-21-2018, 06:48 AM
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Originally Posted by Canadian_CD9A View Post
I could. Has anyone ever had a faulty Omni sensor like this?
Originally Posted by Canadian_CD9A View Post
Replaced the OEM sensor with the Omni sensor. No change
Wasn't this CEL code a problem, before changing to the Omni sensor?

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Old 05-23-2018, 05:00 PM
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After 12 months, my P0122 is finally solved!

I tested out the OEM TPS sensor today with the new harness. Voltage was within spec on at closed throttle and WOT, and remained steady on the voltmeter while wiggling the sensor and the harness. So I bolted it down, and soldered up the harness and plugged it back in. CEL is gone and hasn't come back. The 'dead pedal' effect is gone, bucking and misfiring stopped. It wanted to stall and idle low still, but after a few miles, the idle dip cleared up, too. I'm thinking it may have cleared up the P0410 (secondary air system) code that has been lurking for a while, since I don't hear the emissions pump on all the time anymore either.

So yes, my Omni TPS sensor is JUNK. The original problem was the TPS connector, but swapping out the good TPS sensor for a junk sensor just made things worse.
This car is glorious again.
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Old 05-24-2018, 04:56 AM
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Glad you got it fixed...and very nice of you to post a follow up.
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