1998 Chevy Cavalier TPS Sensor

Tiny
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  • 1998 CHEVROLET CAVALIER
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 200,000 MILES
I have replaced the TPS sensor 5 times. What would be making this sensor go off and make the engine light come on
Tuesday, September 7th, 2010 AT 11:19 AM

15 Replies

Tiny
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What is the exact code number being set?
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Tuesday, September 7th, 2010 AT 11:39 AM
Tiny
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I keep getting Code P0122 which in the manual says throttle Position sensor. I replaced 5 times. What else could be making this go bad or giving this code to pop up?
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Tuesday, September 7th, 2010 AT 11:44 AM
Tiny
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That code doesn't mean you have a bad TPS sensor. It's telling you that the computer is seeing a low voltage signal from the TPS. That can be caused by the sensor itself, the PCM, any of the related wiring or the throttle body itself. The circuit needs to be tested more thoroughly and not just throw a sensor at it.
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Tuesday, September 7th, 2010 AT 11:50 AM
Tiny
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I have been told to look for other things like a vacuum leak or other issues. So I just should check the circuit. Thanks.
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Tuesday, September 7th, 2010 AT 11:55 AM
Tiny
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A vacuum leak has nothing to do with low voltage TPS signal. The TPS circuit needs to be troubleshooted to verify and determine the cause of the low voltage return signal. You have to understand the circuit to be able to do this. You also need a scan tool.
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Tuesday, September 7th, 2010 AT 12:01 PM
Tiny
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Got it. What type of scan tool would you recommend for this type of job?
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Tuesday, September 7th, 2010 AT 12:07 PM
Tiny
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Any one that can read TPS sensor voltage
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Tuesday, September 7th, 2010 AT 12:14 PM
Tiny
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I checked the tps sensor yesterday. I seems to be good and the voltage checks out according to the repair manual. The manual mentions replacing the PCM if everything checks out which it didand the wire harness is fine. Is this correct or is there something else?
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Thursday, September 9th, 2010 AT 10:49 AM
Tiny
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Exactly how did you perform these tests?
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Thursday, September 9th, 2010 AT 11:46 AM
Tiny
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I used a vcom and back probed the sensor with the ignition on but the engine not running which is what the manual called for to test the sensors and harness.
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Thursday, September 9th, 2010 AT 11:50 AM
Tiny
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I advised you to use a scan tool. What you did does not tell you what the computer is seeing.
I'm sure you were not able to find any glitches that way either which would require a lab scope.
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Thursday, September 9th, 2010 AT 11:55 AM
Tiny
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I know. I plan on purchasing one when I get paid. In the mean time I was reading up on this through the repair manuals and your advice that I can do now until then. The scan tools I'm seeing are going for $150.00 and up. That's steep for me now.
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Thursday, September 9th, 2010 AT 12:02 PM
Tiny
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I bet you can have the whole problem diagnosed by a professional for less than $100
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Thursday, September 9th, 2010 AT 1:26 PM
Tiny
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I had a tech look into this with the scan tool and it showed P0122- TPS switch A circuit low. P0405 Exhaust gas Recirculation sensor A circuit Low. P0452 Evaporative Emission System Pressure Switch Low. I see I have a problem with Circuit A being low. What and Where and How can I find Circuit A? The tech. Said for $300 he would look into this. I can't afford this and he said that was just to look into it cause it is electrical. What do you suggest?
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Friday, September 10th, 2010 AT 8:42 AM
Tiny
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I'd say that his prices are a bit outrageous and he's probably quoting you that because he is afraid to tackle the job because he is probably not experienced enough.

It's going to take someone that knows what they are doing but the labor shouldn't be anything over 2 hours.
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Friday, September 10th, 2010 AT 10:31 AM

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