Engine Tps code 63 troubles

Keith cadnum · Jan 26, 2020

New here looking for help. I have a 90 5.0 lx and am having problems with code 63 tps voltage to low. Voltage on the signal wire is .98 and voltage at the pcm is .98 and from what I have read this should be the correct voltage also from what I’ve read the voltage would have to be .5 or less at the pcm to set this code

General karthief · Jan 26, 2020

Clear the code, drive the car around bring it up to operating temp then check again.

Keith cadnum · Jan 26, 2020

General karthief said:
Clear the code, drive the car around bring it up to operating temp then check again.

If I clear the code it throws it immediately. The warmer the car is the worse it runs

Mustang5L5 · Jan 26, 2020

You are correct. Less than 0.5v will set this code.

See this post

code 63

will a code 63 egr cause stalling cold and warm and idle issues

www.stangnet.com

Any other codes? Or this the only one?

Keith cadnum · Jan 26, 2020

Mustang5L5 said:
You are correct. Less than 0.5v will set this code.

See this post

code 63

will a code 63 egr cause stalling cold and warm and idle issues

www.stangnet.com

Any other codes? Or this the only one?

That’s the only code

jrichker · Jan 27, 2020

Keith cadnum said:
That’s the only code

Code 63 - Throttle Position Sensor (TPS) signal too low.

Revised 02-Jul-2009 to update TPS setting procedure & add 10 pin connector layout.

Vref missing (5 volt reference voltage supplied by the computer), bad connections or damaged wiring, TPS sensor failed, TPS sensor way out of adjustment. Use a DVM to check for 5 volts on the Orange wire. If it is missing, look for +5 volts at the Orange wire on the EGR or MAP/Baro sensor located on the firewall near the center of the car. If there is +5 volts on the MAP/Baro sensor, but not on the EGR, clean the #2 & #5 pin on the white 10 pin connector. If there is +5 volts on the EGR but not on the TPS, look for bad wiring inside the engine fuel injector harness.

See the graphic for the 10 pin connector circuit layout.

Setting the TPS voltage
You'll need a Digital Voltmeter (DVM) to do the job.

Wire colors & functions:
Orange/white = 5 volt VREF from the computer
Dark Green/lt green = TPS output to computer
Black/white = Signal ground from computer

Always use the Dark Green/lt green & Black/white wires to set the TPS base voltage.

Do the test with the ignition switch in the Run position without the engine running.

Use the Orange/white & Black white wires to verify the TPS has the correct 5 volts source from the computer.
Setting the TPS: you'll need a good Digital Voltmeter (DVM) to do the job. Set the TPS voltage at .5- 1.1 range. Because of the variables involved with the tolerances of both computer and DVM, I would shoot for somewhere between .6 and 1.0 volts. Unless you have a Fluke or other high grade DVM, the second digit past the decimal point on cheap DVM’s is probably fantasy.

Since the computer zeros out the TPS voltage every time it powers up, playing with the settings isn't an effective aid to performance or drivability. The main purpose of checking the TPS is to make sure it isn't way out of range and causing problems.

The Orange/White wire is the VREF 5 volts from the computer. You use the Dark Green/Lt green wire (TPS signal) and the Black/White wire (TPS ground) to set the TPS. Use a pair of safety pins to probe the TPS connector from the rear of the connector. You may find it a little difficult to make a good connection, but keep trying. Put the safety pins in the Dark Green/Lt green wire and Black/White wire. Make sure the ignition switch is in the Run position but the engine isn't running.

Always adjust the TPS and Idle with the engine at operating temp. Dive it around for a bit if you can and get it nice and warm.

When you probe the leads of the TPS, do not use an engine ground, put the ground probe into the lead of the TPS. You should be connecting both meter probes to the TPS and not one to the TPS and the other to ground.

The TPS is a variable resistor, much like the volume control knob on a cheap radio. We have all heard them crackle and pop when the volume is adjusted. The TPS sensor has the same problem: wear on the resistor element makes places that create electrical noise. This electrical noise confuses the computer, because it expects to see a smooth increase or decrease as the throttle is opened or closed.

TPS testing: most of the time a failed TPS will set code 23 or 63, but not always. Use either an analog meter or a DVM with an analog bar graph and connect the leads as instructed above. Turn the ignition switch to the Run position, but do not start the engine. Note the voltage with the throttle closed. Slowly open the throttle and watch the voltage increase smoothly, slowly close the throttle and watch the voltage decrease smoothly. If the voltage jumps around and isn’t smooth, the TPS has some worn places in the resistor element. When the throttle is closed, make sure that the voltage is the same as what it was when you started. If it varies more than 10%, the TPS is suspect of being worn in the idle range of its travel.

Keith cadnum · Jan 27, 2020

I have the 5 volt reference and the tps voltage is .98 at the sensor and at the pcm. If I clear the code it comes back immediately after start. Voltage also increases smoothly as throttle is opened. I thought the pcm my be defective so I swapped it out with a known good pcm and same story.

General karthief · Jan 27, 2020

Attach a dvm to the Vref wire and jiggle the wires, it may be getting an intermittent signal. The ten pin connectors should be cleaned as suggested.

Mustang5L5 · Jan 27, 2020

My guess is intermittent loose connection. Hit a bump and lose voltage and perhaps it dip low enough to trigger the code.

the 10-pins are notorious for this.

jrichker · Jan 27, 2020

Keith cadnum said:
I have the 5 volt reference and the tps voltage is .98 at the sensor and at the pcm. If I clear the code it comes back immediately after start. Voltage also increases smoothly as throttle is opened. I thought the pcm my be defective so I swapped it out with a known good pcm and same story.

Troubleshooting low or missing 5 volt Vref

All tests done with the ignition switch in the Run position but the engine is not running.

The orange/white wire supplies 5 volts reference (Vref) for the TPS, MAP/Baro and EGR sensors.

Engine Mounted sensors

The TPS and EGR get their 5 volt Vref through the engine mounted fuel injector harness & the 10 pin connectors.

See the graphic for the 10 pin connector circuit layout.

A bad connection or broken wire in the engine mounted fuel injection harness is not uncommon. Check the EGR sensor orange/white wire for good 5 volt Vref. If it is good there, the TPS has either a broken wire or bad connection.
Good 5 volt Vref at the ERG sensor, then you have a 10 pin salt & pepper connecter problem or a computer problem.

Check for 5 volt Vref on the orange/white wire at the firewall mounted MAP/Baro sensor. Good 5 volt Vref there, then the problem is in the 10 pin salt & pepper connectors or in the engine mounted fuel injection harness.

No 5 volt Vref at the MAP/Baro sensor, then the problem is either a broken wire in the main fuel injector harness or the computer has died.

Remove the passenger side kick panel to gain access to the computer.

Locate the orange/white wire (pin 26) on the computer connector and check for 5 volt Vref. Good 5 volt Vref and the computer is OK.

Diagrams courtesy of Tmoss & Stang&2birds

Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs

Keith cadnum · Feb 5, 2020

Tried cleaning both 10 pin connectors and retested all voltages good but code comes right back also noticed that the factory tach swings around to seven grand when cranking

Engine Tps code 63 troubles

Keith cadnum

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General karthief

wonder how much it would cost to ship you a pair

Keith cadnum

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That is…until I whipped out my Bissell

code 63

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General karthief

wonder how much it would cost to ship you a pair

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That is…until I whipped out my Bissell

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