Code 22 MAP (vacuum) or BARO signal out of range. The MAP or BARO sensor is pretty much the same sensor for
both Mass Air & Speed Density cars. The main difference is where it is connected. Mass Air cars vent it to the a
tmosphere, while Speed Density cars connect it to the intake manifold vacuum. Its purpose is to help set a baseline
for the air/fuel mixture by sensing changes in barometric pressure. The MAP or BAP sensor puts out a 5 volt square
wave that changes frequency with variations in atmospheric pressure. The base is 154 HZ at 29.92" of mercury
- dry sunny day at sea level, about 68-72 degrees. You need an oscilloscope or frequency meter to measure it.
There is no way you can use a common cheap voltmeter or DVM to accurately measure the output signal.
The MAP/BARO sensor is mounted on the firewall behind the upper manifold.
Baro or MAP test using frequency meter - run the test key on engine off. The noise from the ignition system will
likely upset the frequency meter. I used a 10 x oscilloscope probe connected from the frequency meter to the
MAP/BAP to reduce the jitter in the meter's readout.
If it is defective, your air/fuel ratio will be off and the car’s performance & emissions will suffer
Some basic checks you can make to be sure that the sensor is getting power & ground:
Note that all resistance tests must be done with power off. Measuring resistance with a circuit powered on
will give false readings and possibly damage the meter.
Check the resistance between the black/white wire on the MAP/BARO sensor and then the black/white wire on
the EGR and the same wire on the TPS. It should be less than 1 ohm. Next check the resistance between the
black/white wire and the negative battery cable. It should be less than 1.5 ohm.
The following power on check requires you to turn the ignition switch to the Run position.
Use a DVM to check for 5 volts on the orange/white wire. If it is missing, look for +5 volts at the orange/white
wire on the TPS or EGR sensors. Use the black/white wire for the ground for the DVM.
Code 63 - Throttle Position Sensor (TPS) signal too low TPS . TPS out of adjustment, or 5 V VREF missing,
broken wiring or bad connections.
Try this... Currently there is some dispute about setting it at .99 volts being worth the effort, but anything
less is probably OK. All you need is less than 1.0 volt at idle and more than 4.25 at Wide Open Throttle (WOT).
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.
Use the Orange/white & Black white wires to verify the TPS has the correct 5 volts source from the computer.
Here’s a TPS tip I got from NoGo50
When you installed the sensor make sure you place it on the peg right and then tighten it down properly. Loosen
the back screw a tiny bit so the sensor can pivot and loosen the front screw enough so you can move it just a
little in very small increments. I wouldn’t try to adjust it using marks. Set it at .97v-.99v, the closer to .99v the better.
(copied from MustangMax, Glendale AZ)
1. 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.
2. 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.
3. Always reset the computer whenever you adjust the TPS or clean/change any sensors. I just pull the battery
lead for 10 minutes.
4. Check the procedure for your year, on my 90 I have to turn the idle screw until it just touches the tab, then
insert a .010 feeler gauge and give it about one more turn. Then you adjust the TPS voltage to .98v, reset the
computer. Start it up, if the idle is to low then turn the screw in until it is just right, then readjust the TPS voltage
to .98v and reset the computer and start it up. The key is to adjust the TPS voltage and reset the computer
whenever the idle screw is changed.
Probable cause: Vref is not present at both sensors, but it seems odd that you found Vref at the TPS.
Do some more measuring before replacing the MAP/Baro sensor.
both Mass Air & Speed Density cars. The main difference is where it is connected. Mass Air cars vent it to the a
tmosphere, while Speed Density cars connect it to the intake manifold vacuum. Its purpose is to help set a baseline
for the air/fuel mixture by sensing changes in barometric pressure. The MAP or BAP sensor puts out a 5 volt square
wave that changes frequency with variations in atmospheric pressure. The base is 154 HZ at 29.92" of mercury
- dry sunny day at sea level, about 68-72 degrees. You need an oscilloscope or frequency meter to measure it.
There is no way you can use a common cheap voltmeter or DVM to accurately measure the output signal.
The MAP/BARO sensor is mounted on the firewall behind the upper manifold.
Baro or MAP test using frequency meter - run the test key on engine off. The noise from the ignition system will
likely upset the frequency meter. I used a 10 x oscilloscope probe connected from the frequency meter to the
MAP/BAP to reduce the jitter in the meter's readout.
If it is defective, your air/fuel ratio will be off and the car’s performance & emissions will suffer
Some basic checks you can make to be sure that the sensor is getting power & ground:
Note that all resistance tests must be done with power off. Measuring resistance with a circuit powered on
will give false readings and possibly damage the meter.
Check the resistance between the black/white wire on the MAP/BARO sensor and then the black/white wire on
the EGR and the same wire on the TPS. It should be less than 1 ohm. Next check the resistance between the
black/white wire and the negative battery cable. It should be less than 1.5 ohm.
The following power on check requires you to turn the ignition switch to the Run position.
Use a DVM to check for 5 volts on the orange/white wire. If it is missing, look for +5 volts at the orange/white
wire on the TPS or EGR sensors. Use the black/white wire for the ground for the DVM.
Code 63 - Throttle Position Sensor (TPS) signal too low TPS . TPS out of adjustment, or 5 V VREF missing,
broken wiring or bad connections.
Try this... Currently there is some dispute about setting it at .99 volts being worth the effort, but anything
less is probably OK. All you need is less than 1.0 volt at idle and more than 4.25 at Wide Open Throttle (WOT).
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.
Use the Orange/white & Black white wires to verify the TPS has the correct 5 volts source from the computer.
Here’s a TPS tip I got from NoGo50
When you installed the sensor make sure you place it on the peg right and then tighten it down properly. Loosen
the back screw a tiny bit so the sensor can pivot and loosen the front screw enough so you can move it just a
little in very small increments. I wouldn’t try to adjust it using marks. Set it at .97v-.99v, the closer to .99v the better.
(copied from MustangMax, Glendale AZ)
1. 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.
2. 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.
3. Always reset the computer whenever you adjust the TPS or clean/change any sensors. I just pull the battery
lead for 10 minutes.
4. Check the procedure for your year, on my 90 I have to turn the idle screw until it just touches the tab, then
insert a .010 feeler gauge and give it about one more turn. Then you adjust the TPS voltage to .98v, reset the
computer. Start it up, if the idle is to low then turn the screw in until it is just right, then readjust the TPS voltage
to .98v and reset the computer and start it up. The key is to adjust the TPS voltage and reset the computer
whenever the idle screw is changed.
Probable cause: Vref is not present at both sensors, but it seems odd that you found Vref at the TPS.
Do some more measuring before replacing the MAP/Baro sensor.
