TPS problems
Thread Starter
Instructor
Joined: Oct 2006
Posts: 104
Likes: 1
From: North Tonawanda New York
TPS problems
Recently replaced my TPS sensor, volts are reading at 4.88 should be at .54 tried adjusting it but only changed it .08, reading a code 21 TPS circuit, and a code 44 02 sensor lean. Please help! Thanks, Ray
Thread Starter
Instructor
Joined: Oct 2006
Posts: 104
Likes: 1
From: North Tonawanda New York
I am using a Mac Tools Mentor 2000 with datastream, and I am coming up with a code 21 and a code 44. Now it says in my 1986 GM shop manual that a code 21 (TPS circuit) could cause a code 44 (o2 sensor lean). I tried adjusting the TPS but it only varies by .08 from both farthest adjusting points, the TPS currently reads 4.88 at idle it's supposed to be at .54 +/-.08
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
TPS is set with key turned on and engine NOT RUNNING. TPS should be adjusted to .54 just sitting. It should be at least 4.0+ with the butterflies fully open (WOT). Again these are set without the engine running, key on ONLY. Check to see that the swing arm on the butterflies is engaged with the TPS. Also check to see if the lever on the TPS is rubbing against the TB and hanging up, this could be giving you a false reading.
Burning Brakes
Joined: Aug 2005
Posts: 1,050
Likes: 0
From: Portsmouth VA
I am using a Mac Tools Mentor 2000 with datastream, and I am coming up with a code 21 and a code 44. Now it says in my 1986 GM shop manual that a code 21 (TPS circuit) could cause a code 44 (o2 sensor lean). I tried adjusting the TPS but it only varies by .08 from both farthest adjusting points, the TPS currently reads 4.88 at idle it's supposed to be at .54 +/-.08
(1) What symptoms does the car have? What exactly were you trying to fix.
(2) Are these 4V readings from the new or old sensor?
Your TPS _might_ be just fine, but it's trying to correct for some other problem (e.g. a vac leak).
Team Owner
Joined: Jan 2003
Posts: 20,324
Likes: 250
From: Summerland B.C. Canada
Your 4.88 looks like your getting the 5 volts reference and not the TPS output signal.
Maybe just a bad TPS.
http://members.shaw.ca/corvette86/Code%2021.pdf
Burning Brakes
Joined: Dec 1999
Posts: 984
Likes: 154
From: Columbia MD
Thread Starter
Instructor
Joined: Oct 2006
Posts: 104
Likes: 1
From: North Tonawanda New York
the sensor is new the reading is comming with the key in the on position and the codes are comming up after i installed the new TPS and nothing is hanging up the lever on the TPS or the TB.
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Thread Starter
Instructor
Joined: Oct 2006
Posts: 104
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From: North Tonawanda New York
Safety Car
Joined: May 1999
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From: Atlantis
Cruise-In I Veteran
The TPS could be bad..... That type failure is not encountered very often however.
Make SURE one terminal of the TPS goes to ground.
Sounds to me like your GROUND terminal is DISCONNECTED.
The CENTER terminal is the one to measure the TPS voltage as sensed by the ECM.
The terminal OPPOSITE the GROUND terminal will have constant +5 volts applied to it which is supplied by the 5 Volt Regulator circuit inside the ECM.
TPS
1 |------- +5 Volts From ECM
2 |------- TPS Voltage +.480~.4.80 Volts To ECM
3 |------- Ground 0 Volts
Kwik and easy check procedure:
1) Volt-Ohmeter on +10 or +20 Volts Range
2) Connect Negative lead to Ground on the engine block
3) Connect Positive lead to one of the TWO 'outside' terminals of the TPS wiring. 1 or 3 in the diagram above.
4) Voltmeter reads 5 Volts?
Move Positive lead to the opposite terminal.
5) Voltmeter reads 5 Volts?
The GROUND wire is disconnected or broken in the wiring harness.
If you read 5 volts on BOTH terminal of the TPS......
With NO GROUND the VOLTAGE will change VERY little when the TPS is moved from one extreme to the other one in it's range of motion.
Either the INTERNAL connection inside the TPS is broken or the ground wire in the harness is not connectred to ground.
Make SURE one terminal of the TPS goes to ground.
Sounds to me like your GROUND terminal is DISCONNECTED.
The CENTER terminal is the one to measure the TPS voltage as sensed by the ECM.
The terminal OPPOSITE the GROUND terminal will have constant +5 volts applied to it which is supplied by the 5 Volt Regulator circuit inside the ECM.
TPS
1 |------- +5 Volts From ECM
2 |------- TPS Voltage +.480~.4.80 Volts To ECM
3 |------- Ground 0 Volts
Kwik and easy check procedure:
1) Volt-Ohmeter on +10 or +20 Volts Range
2) Connect Negative lead to Ground on the engine block
3) Connect Positive lead to one of the TWO 'outside' terminals of the TPS wiring. 1 or 3 in the diagram above.
4) Voltmeter reads 5 Volts?
Move Positive lead to the opposite terminal.
5) Voltmeter reads 5 Volts?
The GROUND wire is disconnected or broken in the wiring harness.
If you read 5 volts on BOTH terminal of the TPS......
With NO GROUND the VOLTAGE will change VERY little when the TPS is moved from one extreme to the other one in it's range of motion.
Either the INTERNAL connection inside the TPS is broken or the ground wire in the harness is not connectred to ground.
