PO221 code
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From: Glendale, AZ
PO221 code
I have a 99 F250 PSD 4wd truck. It is showing a PO221 code.
The code reads as Throttle position sensor, Circuit "B". O'Reilly's code reader wouldn't go deep enough to give me any more info than that.
Does anybody know if circuit B is the throttle pedal assembly or the sensor? Apparently the sensor is different than the pedal assembly.
The problem is intermittent. It runs most of the time but quits occasionally at the most inopportune times.
I read about the #41 fuse so I am going to check that right now.
Any ideas.
Kevin
The code reads as Throttle position sensor, Circuit "B". O'Reilly's code reader wouldn't go deep enough to give me any more info than that.
Does anybody know if circuit B is the throttle pedal assembly or the sensor? Apparently the sensor is different than the pedal assembly.
The problem is intermittent. It runs most of the time but quits occasionally at the most inopportune times.
I read about the #41 fuse so I am going to check that right now.
Any ideas.
Kevin
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From: Glendale, AZ
What is the Idle Validation Switch?
Is the IVS part of the throttle pedal assembly?
Their code reader said TPS Circuit B, but that is probably not a real expensive scanner.
I probably didn't give enough info.
The engine stays running, it just won't come off of idle. I push on the pedal and it does nothing but idle but after a few tries it will go ahead and run properly. The gauges are all still working properly. I saw the check engine light come on 1 time and it went off after about 2 seconds and never came back on again.
A couple of times the engine(at 45 mph) has felt like it was returning back to idle but when I lift on the throttle and push it back down, it will go ahead and continue on at the proper speed.
Kevin
Is the IVS part of the throttle pedal assembly?
Their code reader said TPS Circuit B, but that is probably not a real expensive scanner.
I probably didn't give enough info.
The engine stays running, it just won't come off of idle. I push on the pedal and it does nothing but idle but after a few tries it will go ahead and run properly. The gauges are all still working properly. I saw the check engine light come on 1 time and it went off after about 2 seconds and never came back on again.
A couple of times the engine(at 45 mph) has felt like it was returning back to idle but when I lift on the throttle and push it back down, it will go ahead and continue on at the proper speed.
Kevin
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From: Amarillo, TEXAS!
It's on the throttle position sensor assembly. There are two harnesses going to it, the one with two wires is the idle validation switch, the one with three wires is the throttle position sensor. If the PCM detects that the throttle position sensor has changed to apply throttle, but the IVS is still active, it will disable the TPS to allow only idle speed and set the SES light. On a 99, it's a little microswitch, and you should be able to hear it click when you start to move the pedal. You might need to have your head down low to be able to hear it.
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From: Glendale, AZ
It's on the throttle position sensor assembly. There are two harnesses going to it, the one with two wires is the idle validation switch, the one with three wires is the throttle position sensor. If the PCM detects that the throttle position sensor has changed to apply throttle, but the IVS is still active, it will disable the TPS to allow only idle speed and set the SES light. On a 99, it's a little microswitch, and you should be able to hear it click when you start to move the pedal. You might need to have your head down low to be able to hear it.
I will check it and see if I can hear it click.
My problem is intermittent.
Kevin
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I will unplug it and clean the contacts on it. Mine is getting to be a real problem. It is happening quite often now. I am heading to California with my 63 F100 in the trailer for a car show in June and really don't want to be having a problem with this going over there in the heat of the desert.
Kevin
Kevin
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The switch is open at idle and closed when the throttle is pressed. If you have problems with it and run into a jam, I'm sure you could get a different switch and make it work with a little bit of fabrication, JB Weld, Bondo, cable ties . . . or whatever it takes 
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I took the pedal out of the truck and took the switch out of the assembly. I took my meter and tested it with the continuity tester (sound) and it worked properly 150 out of 150 times.
Maybe it is in the TPS instead???????
Kevin
Maybe it is in the TPS instead???????
Kevin
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Very little movement in the pedal before you hear it click.
I guess if the IVS is the problem and it quits on the road, I could unplug it, take a jumper wire and jump the plug to make it think that the IVS is closed. Would that cause a problem for idle. I am just thinking about a temporary solution until I know for sure what the problem is.
Kevin
I guess if the IVS is the problem and it quits on the road, I could unplug it, take a jumper wire and jump the plug to make it think that the IVS is closed. Would that cause a problem for idle. I am just thinking about a temporary solution until I know for sure what the problem is.
Kevin
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In the end, it could be the throttle sensor. According to the book, if the output voltage crosses 1.6 volts before the IVS switch closes it would produce the same symptoms as a bad switch. If you can get multimeter probes in there you can test it. The signal is on the center pin, the brown wire with white tracer is VREF (should have +5 VDC) and the grey with red tracer should have good continuity to ground. Also, the voltage should rise a minimum of 0.2 volts above the reading at idle before the IVS opens. In other words, if the voltage on the center pin at idle is 0.3 volts, the switch should open when the reading is between 0.5 and 1.6 volts.
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I will see if I can get my meter probes in there to check it out. The throttle pedal is only a couple of minutes to take out so it shouldn't be very hard to test.
I did spray the IVS with some cleaner and blew it out with the air hose. I have been driving the truck today and it is hasn't given me any problems today.
Kevin
I did spray the IVS with some cleaner and blew it out with the air hose. I have been driving the truck today and it is hasn't given me any problems today.
Kevin
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I sprayed the IVS the other day to attempt to clean it. I drove the truck today and never had any problems at all with it. Maybe that will fix it and all will be fine.
I don't drive this truck very often so it is tough to say if it is really fixed. 99 F250 with 78,000 miles. I am heading out to California in a couple of weeks with my trailer and the 63 F100 so I hope that I don't have any problems.
Kevin
I don't drive this truck very often so it is tough to say if it is really fixed. 99 F250 with 78,000 miles. I am heading out to California in a couple of weeks with my trailer and the 63 F100 so I hope that I don't have any problems.
Kevin
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