P0121 - Throttle Position Sensor
01-16-2007, 03:30 PM
#1
P0121 - Throttle Position Sensor
I'm getting this code. I have replaced the TPS and spliced on a new connector, and I still get the code. Anyone have any ideas? I was thinking that maybe since the TPS wire runs right next to the alt that maybe it's getting some kind of weird induced current and screwing with the PCM? Is that possible? I also read something about the WOT screw being set wrong and maxing out the TPS voltage? What's that all about?
When I'm doing logging the TPS never stops reading.
When I'm doing logging the TPS never stops reading.
01-16-2007, 06:59 PM
#2
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I have replaced several of these myself here lately, but mine have been broken..
the spring inside the TPS wasnt letting the sensor spring back to 0, so the pcm was setting off a code..
dont know whats wrong with it this time.....
Post up if you find something out...
the spring inside the TPS wasnt letting the sensor spring back to 0, so the pcm was setting off a code..
dont know whats wrong with it this time.....
Post up if you find something out...
01-16-2007, 07:18 PM
#3
I think I figured it out, I think it's in the tune. There is a table for TPS vs RPM Test Lower table in the engine diagnostics section of the tune. This table basically says that for a given RPM, TPS is expected to be above a certain level. I'm idling at 750 RPM, and the 800 RPM cell was filled with 1% - saying that when the engine is at 800 RPM, the PCM is expecting the TPS to be at least 1%. So for my 750 RPM idle speed, the PCM is expecting to see probably somewhere around .8 or .9% throttle position. I think this is where the problem is. I went ahead and put my 800 RPM cell to zero. Gonna do some more tuning tonight, we'll see if that fixed the problem.
Apparently this is a fairly common problem for people running bigger cams with higher idle speeds.
http://forum.efilive.com/showthread....ighlight=c3907
Apparently this is a fairly common problem for people running bigger cams with higher idle speeds.
http://forum.efilive.com/showthread....ighlight=c3907
02-15-2008, 12:49 AM
#4
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I think I figured it out, I think it's in the tune. There is a table for TPS vs RPM Test Lower table in the engine diagnostics section of the tune. This table basically says that for a given RPM, TPS is expected to be above a certain level. I'm idling at 750 RPM, and the 800 RPM cell was filled with 1% - saying that when the engine is at 800 RPM, the PCM is expecting the TPS to be at least 1%. So for my 750 RPM idle speed, the PCM is expecting to see probably somewhere around .8 or .9% throttle position. I think this is where the problem is. I went ahead and put my 800 RPM cell to zero. Gonna do some more tuning tonight, we'll see if that fixed the problem.
Apparently this is a fairly common problem for people running bigger cams with higher idle speeds.
http://forum.efilive.com/showthread....ighlight=c3907
Apparently this is a fairly common problem for people running bigger cams with higher idle speeds.
http://forum.efilive.com/showthread....ighlight=c3907
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