texasteacher

I have a 2000 Cherokee Classic 4X4, 4.0 L , Automatic.

I am not a mechanic, so bear with me, I am a school teacher who needs to get his ride fixed on the cheap.

I was driving home from work one day and my jeep would not upshift. It stayed in first gear and the engine revved pretty high. On the way home, it did finally start shifting, but it was a very hard shift. This came on pretty suddenly, the transmission had no difficulties up to that point. Since this happened, the shifting still remains hard, it dies easily at idle in park, and there is a strange looking warning light on (looks like a engine or a transmission). The Jeep did get pretty hot shortly before that because of a cooling issue, don't know if it could be related.

I checked the fluid and it is not bright red, bet does not look horrible.

Could this be related to the Throttle Position Sensor?

I need to get it fixed, but cannot spend a ton changing parts. What should I do first? Fluid and filter, TPS? I do not have a trusted mechanic, and I am very weary of transmission specialty shops. I can figure out most things given a little advice and a lot of time.

Any help would be greatly appreciated.

ZINGGG

My suggestion would be to go to an auto parts store and have them hook up a code reader to see if anything comes up.

Sounds to me like your idle air control valve. I'd suggest pulling that and the throttle body and giving em a nice cleaning. Your TPS could be going out. There's a way to test it to make sure it's working correctly

fishtaconc

http://www.naxja.org/forum/showthread.php?t=1015963

The first post has the directions, the last page has a pic of the cable.

Courtesy of tjwalker:

I agree with kjc; the throttle position sensor and TV cable should be verified.
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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.

Any big box parts store will test your codes for free, I recommend you have this done, report back with exact if any codes reported.

texasteacher

Thanks for your suggestions. I probably do need to clean that stuff up. Do you think that the IAC valve could be responsible for the rough shifting and lack of shifting?

fishtaconc

IAC would be responsible for the idle issues, the TPS is in play for the Rough or lack of shifting. Start with the naxja link, its easy, and free to adjust the TV cable.

cruiser54

Think of that light on the dash as a student raising their hand to get your attention.

cherokee104

Does anybody know if they make shift kits for the xj?
I drive a 00 jeep cherokee limited

cruiser54

Before you go that route, adjust your TV cable.

Macoozie

Check fuse #10
Controls a ton of stuff, poor transmission lockup/shifting, fixed a misfire, help on cooling issues etc . . .

Sounds very weird but, after I replaced that blown fuse, everything settled out. Did the cable adjust after that and now its golden.