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P0122 and P0700

Ghost

Member Number 257
NAXJA Member
98 xj Limited 4.0 aw4 242. Throwing these two codes. Clock spring is messed up so I read that it can cause these two codes. I have an clock spring coming so until then I have it unplugged. Jeep still shows these two codes. Is that confirmation it's the TPS?
 
After unplugging the clockspring, did you clear the trouble codes ? Test the TPS and let us know what you find.


TPS failure may have one or more of these Physical Symptoms:

1) The engine loses power and is stalling.
2) The engine will idle, but may die as soon as you press the gas pedal. When driving, it seems as if all power is gone.
3) Sometimes it feels as if the transmission is failed or isn't shifting properly, if at all. If you quickly jump on the gas you might be able to get the transmission to shift, but it won’t shift properly by itself. Shifting manually, the transmission goes through all the gears.

NOTE: The throttle position sensor is also DIRECTLY involved with transmission shifting characteristics. The TPS function should be verified early in the troubleshooting process, when a transmission issue is suspected.

TPS TEST

The TPS is mounted on the throttle body. The TPS is a variable resistor that provides the Powertrain Control Module (PCM) with an input signal (voltage)that represents throttle blade position. The sensor is connected to the throttle blade shaft. As the position of the throttle blade changes, the resistance of the TPS changes. 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 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. It is best 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 5volts. This will vary in an approximate range of from .25 volts at minimum throttle opening (idle), to 4.8volts at WOT wide open throttle.

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:

-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.
 
All I have is a digital volt meter. I'm out of town visiting family. There is 5v in and the ground is showing continuity. I guess I need to just gamble and replace it. It's showing all the symptoms you posted.
 
Did you ever resolve the problem? I have 1998 XJ Sport. Codes p0122, p0123, p0700. Changed TPS twice and still no luck.

I unplugged the clock spring which didn't help until I replaced the TPS. That finally fixed it. I have to replace the clock spring still.
 
Did you replace with factory sensor or aftermarket?

I was out of town so I put an aftermarket one on from Advanced IIRC. It was over Christmas so my choices were limited.
 
Thanks. I've replaced mine and still running rough. Did you have to reset the computer in any way?

Well when I work on this jeep I always try to disconnect the battery and this time I did. I was trying to teach my 16 year old son how to do this repair correctly IF the airbag is armed. With the airbag light off it wasn't but I'm trying to teach him the right way not my way of doing things! LOL!
 
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