Question: TPS

[moedom19]

If tps sensor is bad would the car run, it will start but feels like missing real bad...

 

[gmjunkie]

If tps sensor is bad would the car run, it will start but feels like missing real bad...

Yep,It'll with Default settings in the ECM!! Unplug it and clean the connections and see what happens!! TPS's Sometimes throw a code,Sometimes Not!

If that don't help,use a scanner in Data Mode and find out what it and other components are doing!!

 

[John Robinson]

Tech 1

Yep,It'll with Default settings in the ECM!! Unplug it and clean the connections and see what happens!! TPS's Sometimes throw a code,Sometimes Not!

If that don't help,use a scanner in Data Mode and find out what it and other components are doing!!

Junk do you use a tech 1 to reprogram the ecm when you install a new TPS or after you have unplugged it and then reconnected the TPS. Is there an alternate method of getting the ecm and tps to configure with each other.

 

[gmjunkie]

Junk do you use a tech 1 to reprogram the ecm when you install a new TPS or after you have unplugged it and then reconnected the TPS. Is there an alternate method of getting the ecm and tps to configure with each other.

I usually just dump the codes!! Start her up,it will have already done it by time it gets to closed loop!
If it a pre 92 I set it manually with my Snap On Scanner!!

 

[Schrade]

New TPS (and old one too, if unplugged with the battery CONNECTED) will re-learn the proper range after half a dozen drive cycles, if you don't have a scanner. It will take each gear (if auto) a little higher RPM's until the 'normal' throttle response/range gets calculated.

 

[vetteboy86]

If tps sensor is bad would the car run, it will start but feels like missing real bad...

Why have you narrowed it to the TPS?

 

[moedom19]

I have the code 21.... but now the car started up fine after it cooled down....Is a tsp bad all the time , or can it respond like that....Thank You moedom19

 

[John Robinson]

TPS 101

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[FONT=&quot]Hope this sheds some light on the tps for you.[/FONT]
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Most people do not understand how the TPS works and think it is a mechanical function with the throttle not an electrical signal with the ECM. As in any electrical device it can have a bad connection. First since you are new to this site let me tell you that what Junk says is from someone who is very knowledgeable and if you follow his suggestions you will fix any problem you might have with your car.


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[FONT=&quot]Throttle Position Sensor (TPS)
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[FONT=&quot]The Throttle Position sensor (TPS) is a potentiometer connected to the throttle shaft on the throttle body. It is a potentiometer with one end connected to 5 volts
from the ECM and the other to ECM ground. A third wire is connected to the ECM to measure the voltage from the TP sensor. As the throttle valve angle is changed (accelerator pedal moved), the voltage output of the TP sensor also changes. At a closed throttle position, the voltage output of the TP sensor is low (approximately .5 volt). As the throttle valve opens, the output voltage should be approximately 5 volts.

By monitoring the output voltage from the TP sensor, the ECM can determine fuel delivery based on throttle valve angle (driver demand). A broken or loose TP sensor can cause intermittent burst of fuel from the injectors and cause an unstable idle, because the ECM detects the throttle is moving.

If the TP sensor circuit is open, the ECM will set a DTC 22. If the TP sensor circuit is shorted a DTC 21 will be set. A problem in any of the TP sensor circuits will set either a DTC 21 or 22. Once a DTC is set, the ECM will use a default value for TP sensor, and some vehicle performance will return.

A personal note, when my TPS failed it DID NOT set a code other than to tell me the ECM was bad.

I used a couple of straight pins through the wires to hook the meter on

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[vetteboy86]

I have the code 21.... but now the car started up fine after it cooled down....Is a tsp bad all the time , or can it respond like that....Thank You moedom19

If you have set a TPS code, then replace that sensor. You can check it if you wish. Using two paper clips and a decent DMM will do the trick. Either way, your gonna need to verify the TPS is correct. Because if you put a new one on, you will need to for lack of a better term "calibrate" it correctly.

The TPS is set with the throttle at rest. Usually set to .54 volts or as close as possible. On the high side with the throttle valves wide open, TPS voltage should be at least 4.5 volts.

I will have to look in my manual to tell you which two terminals to probe.

 

[Paul Higg]

A code 21 (just had one) is no big deal. The ECM adjusts to whatever it is sending anyway. Within reason. But if it is bad like mine last summer it will make the car shift hard if you have an auto, and all kinds of other crazy things. EASIEST way to diagnose if is you do NOT HAVE CRUISE CONTROL. If you lose it there is a problem as it controls it and damned near everything ELSE on the car. I bought an adjustable at Eckler's and love it. VERY easy to install (thanks to the Junkie) and easy to adjust!

PS: Ignore Halverson