READ A DROPPING VOLTAGE FROM THE THROTTLE POSITION SENSOR

  • Tiny
  • PaulHomerJr
  • 1994 Oldsmobile Bravada
  • 146,000 miles

What could be causing an analyzer to read a dropping voltage from the throttle position sensor as the RPM increases? I have replaced the TPS three times and the PCM yet the analyzer still continues to say the TPS is bad and shows the voltage dropping as I increase the RPM. It doesn't shift until above 2500 RPM and then shifts very hard. It also is running 200 RPM faster than normal at highway speeds even though it is in OD.

Do you
have the same problem?
Yes
No
Monday, July 16th, 2012 AT 5:57 PM

12 Replies

  • Tiny
  • Docfixit
  • Expert
  • 18,991 posts

What code is comming up?

Was this
answer
helpful?
Yes
No
Monday, July 16th, 2012 AT 6:01 PM
  • Tiny
  • PaulHomerJr
  • Member

22 TPS Sensor Low

Was this
answer
helpful?
Yes
No
Monday, July 16th, 2012 AT 6:32 PM
  • Tiny
  • Docfixit
  • Expert
  • 18,991 posts

Will need a DVOM see diagrams back probe TPS connector Black lead on bottom sensor ground and middle one RED probe. Key on at idle voltage less than 1 volt(.5 v best). Then operate throttle from idle to full meter should go up steady to 4.5 V

Was this
answer
helpful?
Yes
No
Monday, July 16th, 2012 AT 6:43 PM
  • Tiny
  • Docfixit
  • Expert
  • 18,991 posts

Opps

Was this
answer
helpful?
Yes
No
Monday, July 16th, 2012 AT 6:44 PM
  • Tiny
  • PaulHomerJr
  • Member

It starts out at.27 and drops as the throttle is opened.

Was this
answer
helpful?
Yes
No
Monday, July 16th, 2012 AT 6:54 PM
  • Tiny
  • Docfixit
  • Expert
  • 18,991 posts

Check reference voltag must be 5V

Was this
answer
helpful?
Yes
No
Monday, July 16th, 2012 AT 7:03 PM
  • Tiny
  • PaulHomerJr
  • Member

Reference voltage is 5.02. Checked the ground and it's fine also. The low voltage has been the same for all 3 new TPS.

Was this
answer
helpful?
Yes
No
Monday, July 16th, 2012 AT 7:45 PM
  • Tiny
  • Docfixit
  • Expert
  • 18,991 posts

Makes no sence if have 5v REF all TPS is a variable resistor so you say at idle.27v and as open throttl goes to zero

Was this
answer
helpful?
Yes
No
Monday, July 16th, 2012 AT 7:52 PM
  • Tiny
  • PaulHomerJr
  • Member

My point exactly. Could this be an issue with one of the tranny sensors?

Was this
answer
helpful?
Yes
No
Monday, July 16th, 2012 AT 8:00 PM
  • Tiny
  • Docfixit
  • Expert
  • 18,991 posts

Unplug tps use jumper wire from 5v ref and then jumper ground on bottom wire hook up meter across ground and TPS signal open throttle what does it do?

Was this
answer
helpful?
Yes
No
Monday, July 16th, 2012 AT 8:35 PM

Please login or register to post a reply.

Similar Questions