What is a TPS? - 2000 Chevrolet Astro

Did you watch the TPS numbers on a scan tool in your car?
TPS code means TPS bad or wiring or TPS adjustment.
Change the TPS as they cost nothing and do wear out.

Test the tps using procedure below.


Throttle Position Sensor (TPS)
The Throttle Position Sensor (TPS) is connected to the throttle shaft on the throttle body. It is a potentiometer with one end connected to 5 volts from the VCM and the other to ground. A third wire is connected to the VCM to measure the voltage from the TPS. As the throttle valve angle is changed (accelerator pedal moved), the output of the TPS also changes. At a closed throttle position, the output of the TPS is low (approximately 0.5 volts). As the throttle valve opens, the output increases so that, at wide-open throttle, the output voltage should be approximately 4.5 volts. By monitoring the output voltage from the TPS, the VCM can determine fuel delivery based on throttle valve angle (driver demand).

TESTING


See Figures 1, 2 and 3

Backprobe with a high impedance voltmeter at TPS ground terminal and 5 volt reference signal terminal.
With the key ON and engine off, the voltmeter reading should be approximately 5.0 volts.
If the voltage is not as specified, either the wiring to the TPS or the VCM may be faulty. Correct any wiring or VCM faults before continuing test.
Backprobe with a high impedance voltmeter at the TP signal terminal and the sensor ground terminal.
With the key ON and engine off and the throttle closed, the TPS voltage should be approximately 0.5-1.2 volts.
Verify that the TPS voltage increases or decreases smoothly as the throttle is opened or closed. Make sure to open and close the throttle very slowly in order to detect any abnormalities in the TPS voltage reading.
If the sensor voltage is not as specified, replace the sensor.




Fig. Fig. 1: Common Throttle Position Sensor (TPS) wiring diagram (wire color, terminal identification/location may vary on certain models)





Fig. Fig. 2: Using jumper wires and high impedance voltmeter, test between the sensor ground and reference terminals, the voltage should be approximately 5 volts






Fig. Fig. 3: Next test between the sensor signal and ground terminals, verify that the TPS voltage increases or decreases smoothly as the throttle is opened or closed.


REMOVAL & INSTALLATION

Except 1998-99 2.2L Engines
See Figure 4






Fig. Fig. 4: Common Throttle Position Sensor (TPS)
Disconnect the negative battery cable and remove the air cleaner and if equipped, the gasket and bracket.
Disengage the electrical connector.
Unfasten the two TPS attaching screw assemblies.
Remove the TPS from the throttle body assembly.
Remove the TPS seal.

To install:
Install the TPS seal over the throttle shaft.
With the throttle valve closed, install the TPS on the throttle shaft.
Rotate it counterclockwise, to align the mounting holes.
Install the two TPS attaching screws.
Tighten the screws to 18 inch lbs. (2 Nm).
Engage the electrical connector.
If equipped, install the bracket and gasket air cleaner and gasket.Connect the negative battery cable.

1998-99 2.2L Engines
Disconnect the negative battery cable and remove the air cleaner outlet resonator.Remove the throttle body assembly.Unfasten the two TPS attaching screw assemblies.Remove the TPS from the throttle body assembly. To install:
With the throttle valve closed, install the TPS on the throttle body.Install the two TPS attaching screws. Tighten the screws to 27 inch lbs. (3 Nm).Install the throttle body.Install the air cleaner outlet resonator.Connect the negative battery cable.

the 1991 G16a has a pig tail connector, must have 4 wires.
and shares the Injector connector (tricky pin pulls, and all)
that connector you gander is the injector /TPS connector
it has 6 pins but only 4 are for TPS. (yellow /.red are injector)
see page 3 below, for what all this means. last link below.


try to keep in mind, your car has a VIN engine code U (not 6) code 6 , has no pig tail, TPS.
GM uses U code to say, engine is 8valves, TBI, G16a , my guess, (no photos) is your bought TPS is
with tails, and is correct for your 8v engine.

Install, (need feeler gauges to do it)
it's not just thrown on to the car, it must be calibrated.
or the idle switch WILL fail.(and more)
one maker of this TPS is here: (hard to find)
SMP makes one. sMP #TH-147 is for 8V tbi.

http://www.fixkick.com/buy-parts.html#TPS
do not use 16valve parts on your car.

here is the calibration steps.
http://www.fixkick.com/sensors/tests/TPS-testing.html#8v_FSM_cal

the factory page is here
http://www.fixkick.com/TPS/TPS-p91.JPG

http://www.fixkick.com/TPS/TPS-p92.jpg

and page 3 here
http://www.fixkick.com/TPS/TPS-p93.JPG

the last page shows the tricky pin pulls....


you must pull the old pins.' one by one.
then put in then new TPS pins , in the same places of old
matching COLORS.
then do the calibration steps above, using feeler gauges.
same basic steps, from 1989 to 1998.
in 1999 they calibrate it to 0.5vdc, only.
later years, it auto-calibrates.
if the new TPS fails to cure the problem
post the symptoms, and win.

no engine option stated, and is key fact to know here.
eg:
The 5.7L V8 engine does not use a separate Throttle Position Sensor (TPS) on the throttle body.

remove old TPS, and bolt on new.
its like 2 or 3 screws. no big deal.
but needs to be calibrated per fsm.
ill take a wild guess, 3.7L
3.7L Engine and 4.7.

1. Remove air resonator tube at throttle body.
2. Disconnect TPS electrical connector.
3. Remove two TPS mounting screws.
4. Remove TPS.

install
The throttle shaft end of throttle body slides into a socket in TPS. The TPS must be installed so that it can be rotated a few degrees. (If sensor will not rotate, install sensor with throttle shaft on other side of socket tangs). The TPS will be under slight tension when rotated.

1. Install TPS and retaining screws.
2. Tighten screws to 60 inch lbs. (7 Nm) torque.
3. Connect TPS electrical connector to TPS.
4. Manually operate throttle (by hand) to check for any TPS binding before starting engine.
5. Install air cleaner tube to throttle body.

some TPS need calibration
to see what yours needs, read the FSM
or at alldata.com
or here. I think all engines here, are TPS PCM autocalibrated.

read WJ car here
http://www.jeep4x4center.com/knowledge-base/index.htm?utm_source=cj#service

i had the same car.... what mileage.... 200K?
TPS errors. (its real its a real measured error)
this error is catastrophic, , meaning, not just a tad off,
the FSM covers this in details.
clock spring, the Air bag clock spring? has nothing to do with this.
or do you meant the throttle return spring, (my guess?)
the TPS output pin was discovered to have an illegal high voltage
on the output (you can be sure it idid)
spec:
TP Sensor indicated more than 4.50v for 700 ms.

caused by a bad TPS ground wire, or the output pin cut.
or the TPS internals are cracked in half (bad inside) (i have photos)
its bad TPS or bad wires to it. simple huh?
it will not be a bad ECU. as is on the list; it will not.
The jeep has great cheap TPS to buy ofter market,
on other cars not, and can cost $300 , for them
i connect my potable scope and watch the TPS output while i drive.
and find out if it is really truly bad.... hell the part, costs more than my
scope.!
be happy its not new car with throttle by wire, !!!
or the big V8 , whole new throttle body for $1000

recap. bad TPS, bad wires.

the tps on most cars are calibrated.
if you just thrown on a new TPS and not calibrate it, that is
a big failure.
here are the steps
1 key off
2 remove TPS.
3: put back new.
4:
The TPS is mounted to the throttle body. The throttle shaft end of throttle body slides into a socket in the TPS. The TPS must be installed so that it can be rotated a few degrees. (If sensor will not rotate, install sensor with throttle shaft on other side of socket tangs). The TPS will be under slight tension when rotated.

1. Install TPS and retaining screws.
2. Tighten screws to 7 Nm (60 inch lbs.) torque.
3. Connect TPS electrical connector to TPS.
4. Manually operate throttle (by hand) to check for any TPS binding before starting engine.

adjust the TPS for
0.26 volts at minimum throttle opening (idle)

worst case:
the FSM says it auto calibates
if the new TPS errors,. set it to 1/4 volt at idle.
reset ECU , all DCTs using scan tool
pull battery for 5min neg. lug (backup radio codes first)
put back lug
start engine, drive 25miles or till CEL comes on (failures)

The code indicates the TPS is still bad and the code is usually right, but it could be a wiring issue at the TPS connector or less likely a computer issue.
To test the TPS circuit, you need to check voltage and ground from the ECM - 5v is the normal reading between the ECM reference circuit and the ECM ground circuit at the TPS connector. Checking the TPS signal circuit to the ECM requires monitoring the TPS signal on a scan tool while jumping the 5v reference and the signal circuits. The TPS reading should go from high when the circuit is jumpered to low when the jumper is removed.

The 3 wire Throttle Position Sensor (TPS) is mounted on the throttle body and is connected to the throttle blade.
The TPS is a 3wire variable resistor that provides the Powertrain Control Module (PCM) with an input signal (voltage) that represents the throttle blade position of the throttle body. The sensor is connected to the throttle blade shaft. As the position of the throttle blade changes, the resistance (output voltage) of the TPS changes.
The PCM supplies approximately 5 volts to the TPS. The TPS output voltage (input signal to the PCM) represents the throttle blade position. The PCM receives an input signal voltage from the TPS. This will vary in an approximate range of from .26 volts at minimum throttle opening (idle), to 4.49 volts at wide-open throttle. Along with inputs from other sensors, the PCM uses the TPS input to determine current engine operating conditions. In response to engine operating conditions, the PCM will adjust fuel injector pulse width and ignition timing.
The PCM needs to identify the actions and position of the throttle blade at all times. This information is needed to assist in performing the following calculations:

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• THROTTLE POSITION SENSOR

Cherokee, Grand Cherokee, 1999-2005
Throttle Position Sensor

• OPERATION
• REMOVAL & INSTALLATION

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Operation

The 3 wire Throttle Position Sensor (TPS) is mounted on the throttle body and is connected to the throttle blade.
The TPS is a 3wire variable resistor that provides the Powertrain Control Module (PCM) with an input signal (voltage) that represents the throttle blade position of the throttle body. The sensor is connected to the throttle blade shaft. As the position of the throttle blade changes, the resistance (output voltage) of the TPS changes.
The PCM supplies approximately 5 volts to the TPS. The TPS output voltage (input signal to the PCM) represents the throttle blade position. The PCM receives an input signal voltage from the TPS. This will vary in an approximate range of from .26 volts at minimum throttle opening (idle), to 4.49 volts at wide-open throttle. Along with inputs from other sensors, the PCM uses the TPS input to determine current engine operating conditions. In response to engine operating conditions, the PCM will adjust fuel injector pulse width and ignition timing.
The PCM needs to identify the actions and position of the throttle blade at all times. This information is needed to assist in performing the following calculations:


Ignition timing advance Fuel injection pulse-width Idle (learned value or minimum TPS) Off-idle (0.06 volt) Wide Open Throttle (WOT) open loop (2.608 volts above learned idle voltage) Deceleration fuel lean out Fuel cutoff during cranking at WOT (2.608 volts above learned idle voltage) A/C WOT cutoff (certain automatic transmissions only)

Removal & Installation

3.7L & 4.0L

1. Disconnect TPS electrical connector.
2. Remove TPS mounting screws.
3. Remove TPS.

To Install:
The TPS is mounted to the throttle body. The throttle shaft end of throttle body slides into a socket in the TPS. The TPS must be installed so that it can be rotated a few degrees. (If sensor will not rotate, install sensor with throttle shaft on other side of socket tangs). The TPS will be under slight tension when rotated.

1. Install TPS and retaining screws.
2. Tighten screws to 7 Nm (60 inch lbs.) torque.
3. Connect TPS electrical connector to TPS.
4. Manually operate throttle (by hand) to check for any TPS binding before starting engine.

4.7L

1. Remove air duct and air resonator box at throttle body.
2. Disconnect TPS electrical connector.
3. Remove two TPS mounting bolts (screws).
4. Remove TPS from throttle body.

To Install:
The throttle shaft end of throttle body slides into a socket in TPS. The TPS must be installed so that it can be rotated a few degrees. If sensor will not rotate, install sensor with throttle shaft on other side of socket tangs. The TPS will be under slight tension when rotated.

1. Install TPS and two retaining bolts.
2. Tighten bolts to 7 Nm (60 inch lbs.) torque.
3. Manually operate throttle control lever by hand to check for any binding of TPS.
4. Connect TPS electrical connector to TPS.
5. Install air duct/air box to throttle body.

Hope this helps

this is an obd2 trouble code table, it can help you understand the meaning of code.
and for p0120
the Causes:
Sticking throttle return spring
MAP or TPS connector corrosion
Misrouted harness causing chafing
Bad TPS
Bad PCM
Possible Solutions:
If you have access to a scan tool, with KOEO (Key on engine off) observe the TPS voltage. With throttle closed, voltage should be about .45 volts. It should gradually sweep upwards to approximately 4.5 to 5 volts as you depress the throttle. Sometimes only a scope can capture an intermittent glitch in the TPS signal voltage. If you notice a glitch in the TPS sweep voltage, replace the TPS.
NOTE: Some TPS sensors require fine adjustment. If you aren't comfortable with using a DVOM (Digital Volt Ohm meter) to adjust the new TPS, then it's best to take the vehicle to a shop. If the voltage is not .45 volts (+or- .3 volts or so) with the throttle closed or if the reading is "stuck" then unplug the TPS connector. With KOEO check for 5 volts reference voltage present at the connector and a good ground. You can check the signal circuit for continuity by jumping a fused wire between the ground circuit of the TPS connector and the signal circuit. If the TPS reading on the scan tool now reads zero, then replace the TPS. However if that doesn't change the reading to zero, then check for an open or a short on the signal wire and if none is found, suspect a bad PCM. If manipulating the TPS wiring harness causes any change in idle, then suspect bad TPS.

Not likely getting a bad TPS.Your TPS runs off a 5volt reference wire.Using multimeter with key on engine off Check to make sure you have your 5volt reference check for any deformed terminals or broken wires inside insulation.

There are 2 screws that hold the TPS on to the side of the throttle body. Before you take the old TPS off, note where the TPS is located regarding the adjustment slots. Remove the 2 screws, and remove the old TPS, install the new one, and try to achieve the SAME adjustment. If you get the adjustment wrong, the engine will idle up & down. If it does, move the new TPS slightly until the idle smooths out.