tps/???

4byFour · 10-07-2008, 02:40 PM

my check engine light is on so i ran down to the parts store and ran the free diagnostic....is read tps/throttle position sensor circuit A high output....i have changed the tps switch and is still running rough a couple times when i've started it it'll run about 3,000 rpms just idling. then when i'm on the road and get on it a lil...it'll cut out a lil. any ideas????? Thanx

richp · 10-07-2008, 03:49 PM

Disconnect your battery and let it sit for a half hour or so or DISCONNECT the battery, both plus and minus and touch the two DISCONNECTED leads to each other, hmmm, I think that about covers it, just in case it does not, remove the battery and put in your bath tub, touch the two leads together, then go back in the house and get the battery, put it back in and reconnect. What you are doing is draining the capacitors in the ecu so that it has to relearn it's parameters, this might help, it's probably running off the stored ones from the old CPS. Oh, it will run like crap for a while, start it up and take it out and drive it.
Also look for a vacum leak, you don't mention year or engine so thats all I can suggest.

4byFour · 10-07-2008, 06:49 PM

its a 99 tj sport 4.0.....

4byFour · 10-07-2008, 06:52 PM

if you looking at the tps from the bumper whats that sensor to the left of that...and whats the whole circuit A high output about?

bigchris · 10-07-2008, 08:27 PM

The TPS can be tested with a digital voltmeter. The center terminal of the TPS is the output terminal.

With the ignition key in the ON position, check the TPS output voltage at the center terminal wire of the connector. Check this at idle (throttle plate closed) and at Wide Open Throttle (WOT) At idle, TPS output voltage should be greater than.26 volts but less than.95 volts. At wide open throttle, TPS output voltage must be less than 4.49 volts. The output voltage should increase gradually as the throttle plate is slowly opened from idle to WOT.

(taken from a jeep tech man)

if this doesn't help i can get the diag flow chart emailed to you.

richp · 10-07-2008, 10:03 PM

Actually they test better with an analog meter, you can then watch the climb and spot dead spots in the thing. Analog meter, unplug it, put one lead on one pin and another on the other, I forget which way but as you manually operate the throttle [with key off, engine off, key in pocket] the swing on the meter should be smooth and constant, when you hit a dead spot the meter will either jump to infinity or drop to zero. The $15 dollar ones from radio shack will work fine though I don't like the dampening compared to my simpson260 it will be good enough.

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10-07-2008, 02:40 PM	#1
4byFour Jeeper Join Date: Jan 2008 Location: Illinois Posts: 15	tps/??? my check engine light is on so i ran down to the parts store and ran the free diagnostic....is read tps/throttle position sensor circuit A high output....i have changed the tps switch and is still running rough a couple times when i've started it it'll run about 3,000 rpms just idling. then when i'm on the road and get on it a lil...it'll cut out a lil. any ideas????? Thanx

10-07-2008, 08:27 PM	#5
bigchris Jeeper Join Date: Oct 2008 Location: mid-mo. Posts: 38	The TPS can be tested with a digital voltmeter. The center terminal of the TPS is the output terminal. With the ignition key in the ON position, check the TPS output voltage at the center terminal wire of the connector. Check this at idle (throttle plate closed) and at Wide Open Throttle (WOT) At idle, TPS output voltage should be greater than.26 volts but less than.95 volts. At wide open throttle, TPS output voltage must be less than 4.49 volts. The output voltage should increase gradually as the throttle plate is slowly opened from idle to WOT. (taken from a jeep tech man) if this doesn't help i can get the diag flow chart emailed to you. __________________ 02 tj sahara, rough country 4" 33-12.50-15. drop in mopar air filter, 4.0l 5spd, black, black hard top.

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10-07-2008, 03:49 PM	#2
richp Jeeper Join Date: Mar 2007 Location: Pocono mountains Posts: 1,557	Disconnect your battery and let it sit for a half hour or so or DISCONNECT the battery, both plus and minus and touch the two DISCONNECTED leads to each other, hmmm, I think that about covers it, just in case it does not, remove the battery and put in your bath tub, touch the two leads together, then go back in the house and get the battery, put it back in and reconnect. What you are doing is draining the capacitors in the ecu so that it has to relearn it's parameters, this might help, it's probably running off the stored ones from the old CPS. Oh, it will run like crap for a while, start it up and take it out and drive it. Also look for a vacum leak, you don't mention year or engine so thats all I can suggest.

10-07-2008, 06:49 PM	#3
4byFour Jeeper Join Date: Jan 2008 Location: Illinois Posts: 15	its a 99 tj sport 4.0.....

10-07-2008, 06:52 PM	#4
4byFour Jeeper Join Date: Jan 2008 Location: Illinois Posts: 15	if you looking at the tps from the bumper whats that sensor to the left of that...and whats the whole circuit A high output about?

10-07-2008, 10:03 PM	#6
richp Jeeper Join Date: Mar 2007 Location: Pocono mountains Posts: 1,557	Actually they test better with an analog meter, you can then watch the climb and spot dead spots in the thing. Analog meter, unplug it, put one lead on one pin and another on the other, I forget which way but as you manually operate the throttle [with key off, engine off, key in pocket] the swing on the meter should be smooth and constant, when you hit a dead spot the meter will either jump to infinity or drop to zero. The $15 dollar ones from radio shack will work fine though I don't like the dampening compared to my simpson260 it will be good enough.