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- Jeep Grand Cherokee ZJ 1993 to 1998 How to Test and Repalce Throttle Position Sensor
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throttle position sensor
06-23-2011, 02:13 PM
#1
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Year: 1999
Model: Cherokee
Engine: 4.0
throttle position sensor
My Jeep started idling rough and pulsating when accelerating then finally the check engine light came on. I had it checked and it showed two codes for the TPS. I replace it and the battery at the same time to let the computer reset. Fire it up and same thing....get it diagnosed and one code for TPS....did I do something wrong?
06-23-2011, 02:41 PM
#2
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Year: 1988
Model: Cherokee
Engine: 4.0
I don't know if the TPS is adjustable on a 1999, There is an adjustment on my 1988 Renix. Did you just start the vehicle up, or did you take it for a long drive with the new TPS. It takes a while of driving the vehicle for the ECU to learn the new sensor sometimes. Give it a try and get back to us! 
06-23-2011, 04:14 PM
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Year: 1996
Model: Cherokee
Engine: 4.0
The post Renix TPS is a 3 lead unit and not adjustable. It wouldn't be uncommon for an aftermarket sensor to not work correctly, so don't be surprised if its defective.
They can be tested, and the visual part is easier if you have an analog VOM. With the ignition in the "on" position, one of the leads supplies 5v, another is ground, and the remaining lead is the output. On my '96 the output indicated .76v with the throttle closed and 3.8V or so wide open. The transition in voltage needs to be a linear progression from closed to open.
They can be tested, and the visual part is easier if you have an analog VOM. With the ignition in the "on" position, one of the leads supplies 5v, another is ground, and the remaining lead is the output. On my '96 the output indicated .76v with the throttle closed and 3.8V or so wide open. The transition in voltage needs to be a linear progression from closed to open.
06-23-2011, 06:30 PM
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Year: 1999
Model: Cherokee
Engine: 4.0
The post Renix TPS is a 3 lead unit and not adjustable. It wouldn't be uncommon for an aftermarket sensor to not work correctly, so don't be surprised if its defective.
They can be tested, and the visual part is easier if you have an analog VOM. With the ignition in the "on" position, one of the leads supplies 5v, another is ground, and the remaining lead is the output. On my '96 the output indicated .76v with the throttle closed and 3.8V or so wide open. The transition in voltage needs to be a linear progression from closed to open.
They can be tested, and the visual part is easier if you have an analog VOM. With the ignition in the "on" position, one of the leads supplies 5v, another is ground, and the remaining lead is the output. On my '96 the output indicated .76v with the throttle closed and 3.8V or so wide open. The transition in voltage needs to be a linear progression from closed to open.
06-23-2011, 08:44 PM
#6
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Year: 1999
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I disconnected the battery and every sensor I could see for an hour and same thing..I sucked a small amount of water in the KanN filter about two weeks ago and I think that's the culprit ...pulled all plugs and turned it over and no water in any of the cylinders though..i wd'd the cylinders AND throttle body just in case..should i not have sprayed the throttle body?? have I'm kinda green with a meter but I will give it a try!
06-24-2011, 06:34 AM
#7
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Year: 1997 & 1998
Model: Cherokee
Engine: 4.0
I have to agree with the mention of a possibly defective TPS. Between all three post '96 XJs I've owned or own, I've replaced them several times. They just don't seem to last and that's from different parts outlets. If the code persists much longer, I'd suggest taking it back for another.
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07-08-2011, 12:54 PM
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Year: 1999
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The throttle position sensor is connected to the throttle shaft on the throttle body. It sends throttle valve angle information to the PCM. The PCM uses this information to determine how much fuel the engine needs. The TPS is really just a simple potentiometer with one end connected to 5 volts from the PCM and the other to ground. A third wire is connected to the PCM. As you move the accelerator pedal with your foot, the output of the TPS changes. At a closed throttle position, the output of the TPS is low, about a half a volt. As the throttle valve opens, the output increases so that, at wide open throttle, the output voltage should be above 3.9 volts. Testing can be performed with an electrical meter. Analog meter is best. You are looking for a smooth sweep of voltage throughout the entire throttle band. While slowly opening and closing the throttle, take note to the movement of the voltmeter needle. There should be a direct relationship between the needle motion to the motion of the throttle. If at anytime the needle moves abruptly or inconsistently with the movement of the throttle, the TPS is bad
You should have 5 volts going into the TPS. At idle, TPS output voltage must be greater than 200 millivolts. At wide open throttle (WOT), TPS output voltage must be less than 4.8 volts.. The best is to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5 volts. One of the other wires should show .26V (or so). The other wire will be the ground and should show no voltage. Move the throttle and look for smooth meter response up to the 4.49 at WOT.
Perform the test procedure again and wiggle and/or tap on the TPS while you watch the meter. If you notice any flat spots or abrupt changes in the meter readings, replace the TPS.
The TPS is sensitive to heat, moisture and vibration leading to the failure of some units. The sensor is a sealed unit and cannot be repaired only replaced. A TPS may fail gradually leading to a number of symptoms which can include one or more of the following: -
NOTE: The throttle position sensor is also DIRECTLY involved with transmission shifting characteristics! It should be verified early in the troubleshooting process, when a transmission issue is suspected!
• Poor idle control: The TPS is used by the ECU to determine if the throttle is closed and the car should be using the Idle Air Control Valve exclusively for idle control. A fault TPS sensor can confuse the ECU causing the idle to be erratic or "hunting".
• High Idle Speed: The TPS may report faulty values causing the engine idle speed to be increased above normal. This is normally found in conjunction with a slow engine return to idle speed symptom.
• Slow engine return to idle: A failing TPS can report the minimum throttle position values incorrectly which can stop the engine entering idle mode when the throttle is closed. Normally when the throttle is closed the engine fuel injectors will be deactivated until a defined engine RPM speed is reached and the engine brought smoothly to idle speed. When failing a TPS will not report the throttle closed and fueling will continue causing the engine to return to idle very slowly.
• Engine Hesitation on Throttle Application: The TPS is also used by the ECU to determine if the driver has applied the throttle quicker than the Manifold Air Pressure sensor can read. The fueling is adjusted acordingly to cope with the sudden increase in air volume, however a faulty sensor can cause the ECU to ignore this data and the engine will "hesitate" when applying the throttle. In extreme cases with the engine at idle, a sudden application of full throttle can stall the engine.
• Engine Misfire: A fault TPS can report values outside the deined acceptable range causing the ECU to incorrectly fuel the engine. This is noticable as a slight misfire and can trigger the misfire detection software and/or Malfunction Indicator Lamp (MIL) light on the dashboard. Extreme cases can cause excessing misfires resulting in one or more cylinders being shut down to prevent engine and catalytic converter damage.
You should have 5 volts going into the TPS. At idle, TPS output voltage must be greater than 200 millivolts. At wide open throttle (WOT), TPS output voltage must be less than 4.8 volts.. The best is to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5 volts. One of the other wires should show .26V (or so). The other wire will be the ground and should show no voltage. Move the throttle and look for smooth meter response up to the 4.49 at WOT.
Perform the test procedure again and wiggle and/or tap on the TPS while you watch the meter. If you notice any flat spots or abrupt changes in the meter readings, replace the TPS.
The TPS is sensitive to heat, moisture and vibration leading to the failure of some units. The sensor is a sealed unit and cannot be repaired only replaced. A TPS may fail gradually leading to a number of symptoms which can include one or more of the following: -
NOTE: The throttle position sensor is also DIRECTLY involved with transmission shifting characteristics! It should be verified early in the troubleshooting process, when a transmission issue is suspected!
• Poor idle control: The TPS is used by the ECU to determine if the throttle is closed and the car should be using the Idle Air Control Valve exclusively for idle control. A fault TPS sensor can confuse the ECU causing the idle to be erratic or "hunting".
• High Idle Speed: The TPS may report faulty values causing the engine idle speed to be increased above normal. This is normally found in conjunction with a slow engine return to idle speed symptom.
• Slow engine return to idle: A failing TPS can report the minimum throttle position values incorrectly which can stop the engine entering idle mode when the throttle is closed. Normally when the throttle is closed the engine fuel injectors will be deactivated until a defined engine RPM speed is reached and the engine brought smoothly to idle speed. When failing a TPS will not report the throttle closed and fueling will continue causing the engine to return to idle very slowly.
• Engine Hesitation on Throttle Application: The TPS is also used by the ECU to determine if the driver has applied the throttle quicker than the Manifold Air Pressure sensor can read. The fueling is adjusted acordingly to cope with the sudden increase in air volume, however a faulty sensor can cause the ECU to ignore this data and the engine will "hesitate" when applying the throttle. In extreme cases with the engine at idle, a sudden application of full throttle can stall the engine.
• Engine Misfire: A fault TPS can report values outside the deined acceptable range causing the ECU to incorrectly fuel the engine. This is noticable as a slight misfire and can trigger the misfire detection software and/or Malfunction Indicator Lamp (MIL) light on the dashboard. Extreme cases can cause excessing misfires resulting in one or more cylinders being shut down to prevent engine and catalytic converter damage.
08-19-2015, 08:34 AM
#11
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Year: 98
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The throttle position sensor is connected to the throttle shaft on the throttle body. It sends throttle valve angle information to the PCM. The PCM uses this information to determine how much fuel the engine needs. The TPS is really just a simple potentiometer with one end connected to 5 volts from the PCM and the other to ground. A third wire is connected to the PCM. As you move the accelerator pedal with your foot, the output of the TPS changes. At a closed throttle position, the output of the TPS is low, about a half a volt. As the throttle valve opens, the output increases so that, at wide open throttle, the output voltage should be above 3.9 volts. Testing can be performed with an electrical meter. Analog meter is best. You are looking for a smooth sweep of voltage throughout the entire throttle band. While slowly opening and closing the throttle, take note to the movement of the voltmeter needle. There should be a direct relationship between the needle motion to the motion of the throttle. If at anytime the needle moves abruptly or inconsistently with the movement of the throttle, the TPS is bad
You should have 5 volts going into the TPS. At idle, TPS output voltage must be greater than 200 millivolts. At wide open throttle (WOT), TPS output voltage must be less than 4.8 volts.. The best is to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5 volts. One of the other wires should show .26V (or so). The other wire will be the ground and should show no voltage. Move the throttle and look for smooth meter response up to the 4.49 at WOT.
Perform the test procedure again and wiggle and/or tap on the TPS while you watch the meter. If you notice any flat spots or abrupt changes in the meter readings, replace the TPS.
The TPS is sensitive to heat, moisture and vibration leading to the failure of some units. The sensor is a sealed unit and cannot be repaired only replaced. A TPS may fail gradually leading to a number of symptoms which can include one or more of the following: -
NOTE: The throttle position sensor is also DIRECTLY involved with transmission shifting characteristics! It should be verified early in the troubleshooting process, when a transmission issue is suspected!
• Poor idle control: The TPS is used by the ECU to determine if the throttle is closed and the car should be using the Idle Air Control Valve exclusively for idle control. A fault TPS sensor can confuse the ECU causing the idle to be erratic or "hunting".
• High Idle Speed: The TPS may report faulty values causing the engine idle speed to be increased above normal. This is normally found in conjunction with a slow engine return to idle speed symptom.
• Slow engine return to idle: A failing TPS can report the minimum throttle position values incorrectly which can stop the engine entering idle mode when the throttle is closed. Normally when the throttle is closed the engine fuel injectors will be deactivated until a defined engine RPM speed is reached and the engine brought smoothly to idle speed. When failing a TPS will not report the throttle closed and fueling will continue causing the engine to return to idle very slowly.
• Engine Hesitation on Throttle Application: The TPS is also used by the ECU to determine if the driver has applied the throttle quicker than the Manifold Air Pressure sensor can read. The fueling is adjusted acordingly to cope with the sudden increase in air volume, however a faulty sensor can cause the ECU to ignore this data and the engine will "hesitate" when applying the throttle. In extreme cases with the engine at idle, a sudden application of full throttle can stall the engine.
• Engine Misfire: A fault TPS can report values outside the deined acceptable range causing the ECU to incorrectly fuel the engine. This is noticable as a slight misfire and can trigger the misfire detection software and/or Malfunction Indicator Lamp (MIL) light on the dashboard. Extreme cases can cause excessing misfires resulting in one or more cylinders being shut down to prevent engine and catalytic converter damage.
You should have 5 volts going into the TPS. At idle, TPS output voltage must be greater than 200 millivolts. At wide open throttle (WOT), TPS output voltage must be less than 4.8 volts.. The best is to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5 volts. One of the other wires should show .26V (or so). The other wire will be the ground and should show no voltage. Move the throttle and look for smooth meter response up to the 4.49 at WOT.
Perform the test procedure again and wiggle and/or tap on the TPS while you watch the meter. If you notice any flat spots or abrupt changes in the meter readings, replace the TPS.
The TPS is sensitive to heat, moisture and vibration leading to the failure of some units. The sensor is a sealed unit and cannot be repaired only replaced. A TPS may fail gradually leading to a number of symptoms which can include one or more of the following: -
NOTE: The throttle position sensor is also DIRECTLY involved with transmission shifting characteristics! It should be verified early in the troubleshooting process, when a transmission issue is suspected!
• Poor idle control: The TPS is used by the ECU to determine if the throttle is closed and the car should be using the Idle Air Control Valve exclusively for idle control. A fault TPS sensor can confuse the ECU causing the idle to be erratic or "hunting".
• High Idle Speed: The TPS may report faulty values causing the engine idle speed to be increased above normal. This is normally found in conjunction with a slow engine return to idle speed symptom.
• Slow engine return to idle: A failing TPS can report the minimum throttle position values incorrectly which can stop the engine entering idle mode when the throttle is closed. Normally when the throttle is closed the engine fuel injectors will be deactivated until a defined engine RPM speed is reached and the engine brought smoothly to idle speed. When failing a TPS will not report the throttle closed and fueling will continue causing the engine to return to idle very slowly.
• Engine Hesitation on Throttle Application: The TPS is also used by the ECU to determine if the driver has applied the throttle quicker than the Manifold Air Pressure sensor can read. The fueling is adjusted acordingly to cope with the sudden increase in air volume, however a faulty sensor can cause the ECU to ignore this data and the engine will "hesitate" when applying the throttle. In extreme cases with the engine at idle, a sudden application of full throttle can stall the engine.
• Engine Misfire: A fault TPS can report values outside the deined acceptable range causing the ECU to incorrectly fuel the engine. This is noticable as a slight misfire and can trigger the misfire detection software and/or Malfunction Indicator Lamp (MIL) light on the dashboard. Extreme cases can cause excessing misfires resulting in one or more cylinders being shut down to prevent engine and catalytic converter damage.
I dont mean to piggy back, but the threads been dead a while and I believe I'm having a TPS problem. It only read between .76 at idle and 3.6 at WOT. I replaced the sensor, and actually got even lower readings. I'm sure I wouldn't be the first person to get a bum part from autozone, but is there something else I should check? I cleaned the throttle body a few months ago and the grounds look fine.
08-19-2015, 09:16 AM
#13
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Year: 1999
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I just spent half an hour watching a youtube video on TPS, and I could have easily just read this instead. Excellent information.
I dont mean to piggy back, but the threads been dead a while and I believe I'm having a TPS problem. It only read between .76 at idle and 3.6 at WOT. I replaced the sensor, and actually got even lower readings. I'm sure I wouldn't be the first person to get a bum part from autozone, but is there something else I should check? I cleaned the throttle body a few months ago and the grounds look fine.
I dont mean to piggy back, but the threads been dead a while and I believe I'm having a TPS problem. It only read between .76 at idle and 3.6 at WOT. I replaced the sensor, and actually got even lower readings. I'm sure I wouldn't be the first person to get a bum part from autozone, but is there something else I should check? I cleaned the throttle body a few months ago and the grounds look fine.
BWD TPS's suck. I went through several, all of which were out of spec. The OEM TPS is the only way to go.
Do this though...
Under the hood - manually move the throttle to WOT. The cam (stop) on the linkage should contact the step on the TB. If it doesn't, disconnect the transmission kick down linkage and see if it's interfering. If it is, adjust the kick down cable.
At idle the linkage should contact the stop screw on the TB. Do not adjust this screw.
08-19-2015, 01:39 PM
#14
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Year: 98
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BWD TPS's suck. I went through several, all of which were out of spec. The OEM TPS is the only way to go.
Do this though...
Under the hood - manually move the throttle to WOT. The cam (stop) on the linkage should contact the step on the TB. If it doesn't, disconnect the transmission kick down linkage and see if it's interfering. If it is, adjust the kick down cable.
At idle the linkage should contact the stop screw on the TB. Do not adjust this screw.
Do this though...
Under the hood - manually move the throttle to WOT. The cam (stop) on the linkage should contact the step on the TB. If it doesn't, disconnect the transmission kick down linkage and see if it's interfering. If it is, adjust the kick down cable.
At idle the linkage should contact the stop screw on the TB. Do not adjust this screw.
08-19-2015, 03:19 PM
#15
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Year: 1999
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Engine: 4.0
Better late than never on the vehicle specs. I usually don't venture any suggestions unless I know the vehicle specs.
If you look in your factory service manual for your Jeep you will find the TPS specs.
Good luck.
