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Throttle Position Sensor (code P0122)


UKTJ

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Last week I had a check engine light come on.  I checked the code (using the on three times technique) and identified the issue as P0122 Throttle Position Circuit 'A' Low Voltage.  I looked online and found this is usually a bad sensor.  I found this useful video on checking the sensor.

 

TPS video

 

I have just followed the process in the video and 'back probed' the TPS connector.  I get the readings as per the video initially.  Then, when I rotate the throttle the voltage climbs, but only as far as about 3.8v.  No jumping back, a steady climb, but not as high as the c.4.5v stated on the video.  Is the difference between 4.5 and 3.8v likely to be the source of the "Low Voltage" and therefore the P0122 code?  If so I am guessing a new sensor is the likely remedy.

 

As a aside, while doing this I tried to remove the connector into the sensor to see where the back probe had to be inserted.  In doing so I managed to snap the clip that holds the connector on, this part...

image.thumb.png.3b0b502213a77981414b0f0a2f9f9033.png

 

Does anybody know the official name for this or the part number so I can try and find a replacement?

 

Thanks in advance.

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3 hours ago, V said:

I think these could be what you are looking for

WALKER PRODUCTS 2701064

WVE 1P1692

 

Mopar part number is 5013999AA

In the jungle that is TJ part selection by year it seems that one is for 1997 to 2001 TJs.  For my 2002 TJ it looks like this is the one.  I was thrown as initially I was looking in the same section on RockAuto as the TPS sensor itself was in (ie Fuel & Air), but the connectors are (unsurprisingly I guess) under Electrical Connectors.

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Make sure the cable at full throttle is actually opening the butterfly fully.

That could be the reason for only getting 3.8v when the pedal is depressed. Or were you operating the quadrant by hand when testing?

 

Some TPS sensors are adjustable, the holes in the body are elongated to allow for a couple of degrees of rotation?

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16 hours ago, UKTJ said:

For my 2002 TJ it looks like this

 

I'm glad you found the correct part, I didn't know it had been changed for 2002. It does annoy me that vehicle manufacturers change parts slightly for no obvious reason. Perhaps there was some pointless legislation demanding a slide lock tab on the connector or Daimler just wanted to disrupt the pattern part industry and frustrate customers that hold their own spares stock?

 

Is the 2002 TPS different from the 2001?

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8 minutes ago, V said:

Is the 2002 TPS different from the 2001?

I just looked. They are slightly different on the connectors making them incompatible with the 2002 wiring harness. That's a useful thing to remember when buying parts. Now I will have to cross-reference the change on WJ/WG Grand Cherokee to see if it is also affected.

 

The later 2002-2006 TPS with part numbers 05019411AB, 05019411AC, 05019411AD, 05086203AA, 2073600AA, 4874371AD, 5019411AA, 5019411AB, 5019411AC, 5019411AD, 5073600AA, 5086203AA, 56027942A3, 56027942AD, 56027942AF, 68404428AA

Used in the following vehicles

  • DODGE DAKOTA 2002-2006
  • DODGE DURANGO 2004-2006
  • DODGE RAM 1500 PICKUP 2002-2006
  • JEEP COMMANDER 2006
  • JEEP GRAND CHEROKEE 2002-2006
  • JEEP LIBERTY 2002-2006
  • JEEP WRANGLER 2002-2006
  • MITSUBISHI RAIDER 2006

The 1997-2001 TPS with part numbers 4863996, 4874371, 4874371AB, 4874371AC, 56027942, 68433984AA

  • DODGE DAKOTA 1997-2001
  • DODGE VIPER 1998-2002
  • JEEP CHEROKEE 1997-2001
  • JEEP GRAND CHEROKEE 1997-2001
  • JEEP WRANGLER 1997-2001

The 1992-1996 TPS with part numbers 05234904, 4626051, 4636999, 4637072, 4761871, 4761871AB, 5234904, 68405575AA

  • CHRYSLER DYNASTY 1991-1992
  • CHRYSLER LEBARON 1991-1993
  • CHRYSLER SHADOW 1991-1994
  • DODGE CARAVAN 1991-1995
  • DODGE D150 PICKUP 1992-1993
  • DODGE D250 PICKUP 1992-1993
  • DODGE D350 PICKUP 1992-1993
  • DODGE DAKOTA 1991-1993
  • DODGE DAYTONA 1991-1993
  • DODGE RAMCHARGER 1992-1996
  • DODGE SHADOW 1991-1994
  • DODGE SPIRIT 1991-1995
  • DODGE VIPER 1992-1997
  • DODGE W150 PICKUP 1992-1993
  • DODGE W250 PICKUP 1992-1993
  • DODGE W350 PICKUP 1992-1993
  • JEEP CHEROKEE 1991-1996
  • JEEP COMANCHE 1991-1992
  • JEEP GRAND CHEROKEE 1993-1996
  • JEEP WRANGLER 1991-1997
  • PLYMOUTH ACCLAIM 1991-1995
  • PLYMOUTH SUNDANCE 1991-1994
  • PLYMOUTH VOYAGER 1991-1995
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9 hours ago, Ludders said:

Make sure the cable at full throttle is actually opening the butterfly fully.

That could be the reason for only getting 3.8v when the pedal is depressed. Or were you operating the quadrant by hand when testing?

 

Some TPS sensors are adjustable, the holes in the body are elongated to allow for a couple of degrees of rotation?

I was operating by hand.  I've ordered a new TPS from RockAuto, made sense as I had to order the new connector having snapped off the locking tab.  I am sure I will be back asking more questions when they arrive, fitting the TPS will be OK, but doing wiring on the connector will not be something I relish.

 

In the meantime I have no adverse symptoms and the connector is 'secured' into the TPS with an elastic band 😳

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Glad new parts are on the way.  I now also have code P0123, which is high voltage in the TPS circuit.  Hopefully a new TPS, connector and wiring will resolve.

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My replacement TPS and connector have now arrived (4 days ahead of estimate - great job again RockAuto).  Just looking for thoughts on the connector install.  It comes with no instructions and I can’t find any help online so far.  The connector is shipped with the three connecting wires with a terminal on each end (that fits into the back of the connector itself) and three separate butt connectors.

 

I have yet to investigate on the Jeep as this means starting to pull the harness apart.  But the wires do not look long enough to reach very far to connect at the other end, they are about 45cm long.

 

Has anyone replaced one of these before?  Is the approach to butt connect to the existing three wires?  Ultimately where do these three wires run to?

 

I have looked online for wiring diagrams, but I am pretty ignorant on such matters and can’t make head nor tail of them.

 

Thanks in advance.

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I really do dislike anything electrical, well what I really dislike is that I don't understand it.

 

I just went out to try and follow the wiring from the TPS.  But before doing so I had to move the Jeep.  Now when I start the engine I do not get a check engine light.  Using the off to run three time quickly trick I still see the codes P0122 and P0123, but the Jeep is still exhibiting none of the symptoms of those codes that I have found listed online.

 

If the the codes were caused by an intermittent 'glitch' will the check engine light stop showing if the Jeep runs normally for a period of time?  I am tempted to disconnect the battery to clear the codes and see if they return.  I am not looking tp put my head in the sand, I have the replacement parts now so can change them.  But I have a fair bit on this weekend and if the Jeep is running OK it would be handy to be able to delay any fix until after Slindon, next week.

 

Any thoughts much appreciated.

 

 

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Yes, the Check Engine Lamp will illuminate for faults that are present while the engine is running. The lamp will go off for intermittent faults but a Diagnostic Trouble Code (DTC) will be stored the last time the fault occurred. DTCs are usually stored so that they can be retrieved with a scan tool later. Some older systems would clear DTCs after 50 good engine starts or disconnecting the battery but I think modern ECU's have eMMC flash memory storage and keep them until manually cleared.

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1 hour ago, V said:

Yes, the Check Engine Lamp will illuminate for faults that are present while the engine is running. The lamp will go off for intermittent faults but a Diagnostic Trouble Code (DTC) will be stored the last time the fault occurred. DTCs are usually stored so that they can be retrieved with a scan tool later. Some older systems would clear DTCs after 50 good engine starts or disconnecting the battery but I think modern ECU's have eMMC flash memory storage and keep them until manually cleared.

Thanks, I will have a go at disconnecting.  From reading online I believe that works on the TJ.

 

I have found the relevant wiring diagram in my Haynes manual, but I have no idea how to read it.

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