Resetting Throttle Position Sensor

[jertum]

Hello all, hope you're well.

I've started having throttle issues with my 2002 1.3 Mk6 again.

Occasionally, the revs will stick when changing gear and hesitate by a couple of seconds before dropping. It really does make the car difficult to drive safely.

Since having a new Idle Control Valve installed, the car idles perfectly.

I bought one of those cheap car scanners and it came up with a fault code for the Throttle Position Sensor.

Is it really necessary to replace the sensor, or can it be reset/re-calibrated in some way? I've seen online that you can do this with other car brands by going through a process of pressing the pedal slowly and releasing it over and over again with the ignition 'half on'. Is this the case with Fords too? I'm reluctant to do it in case it throws the whole system off!

Disconnecting the battery for an hour or so seemed to temporarily cure the problem but it was back within a few days.

Thanks in advance.

[Dan62]

The 1.3's accelerator pedal is mechanically attached to the throttle body, its not an electronic control like the 16 valve engines.

Check the accelerator cable routing to the throttle body, no kinks or sharp bends.

The pedal should feel smooth when pressed and return to the full upright position when released.

The inner cable can also fray over time so its worth removing the cable and checking for binds.

[jertum]

Thanks for that.

You're right - the pedal is mechanically attached to the throttle body. However, it appears there is a throttle position sensor attached to the throttle body itself. I don't really want to replace it as apparently it can be a tricky process - something to do with the bolts dropping into the throttle body and causing all sorts of problems when removing the TPS.

By the way, I have no knowledge or experience when it comes to cars so you could well be right. I'm just going by what the Haynes Manual says.

[Dan62]

Yes, the throttle position sensor is attached to the throttle body and it would appear to be working as it knows the throttle is open when it should be closed.

[jertum]

I've just scanned the car again. It came up with fault code P0122.

According to the internet:

A P0122 code means that the the car's computer has detected that the TPS (throttle position sensor) is reporting too low a voltage. On some vehicles that lower limit is 0.17 - 0.20 volts (V). Did you adjust it when you installed it? If the signal value is less than .17V then the PCM sets this code. Could be an open or a short to ground in the signal circuit. Or you may have lost the 5Volt reference voltage.

Read more at: http://www.obd-codes.com/p0122
Copyright © OBD-Codes.com

All that means very little to me, can anyone explain? Does this mean that the TPS is likely to need replacing, or is it more likely to mean that the wiring to the TPS is dodgy?

Thanks

[Dan62]

It could be either.

Did you unplug the sensor or other connectors at any time before the code appeared ?

[jertum]

No, I've not touched the TPS at all for fear of causing further problems. A few people seem to have had trouble with the multi plug linked to the sensor - does this sound plausible, given that it's giving inaccurate readings?

Does this appear to be the correct component?

http://www.fordpartsuk.com/shop/ford_fiesta_throttle_position_sensor_jumper__f_1150138_c_341.htm

Sorry if I'm asking a lot of stupid questions and thanks for your help so far.

[Dan62]

It could be the connector and I have no idea if that's the correct part.

The only thing that seems odd is your symptom of intermittent high engine RPM doesn't match the fault code that I can see.

You have a throttle flap that is mechanically operated from the accelerator pedal, the only way the RPM can increase is if the throttle valve is open, the idle control valve is opening or you have an air leak around the manifold.

A sensor cannot open the throttle valve and I doubt it would cause the the idle control valve to open higher than expected idle speed, but perhaps it does.

Sorry, I am out of ideas or suggestions.

[donthaveaford]

I realize this is a super old thread but to clear up the confusion and maybe help anyone else trawling the web with a similar problem

What Dan62 is saying is slightly misleading

Yes the pedal is mechanically operated with a cable which in turn opens and closes the butterfly valve in the throttle body, in layman terms the sensor tells the ECU if the buttfly valve is open, closed or somewhere in between

So whilst the sensor won't be physically opening the valve it can still malfunction and send a signal to the ecu that isn't inline with what the butterfly valve is doing

For example: If the butterfly valve in the throttle body is all the way open but the sensor is telling the ECU the valve is closed the car may decrease the amount of fuel being injected into the engine to mix with what it believes is a very small amount of air the car will struggle to move under it's own power as the air fuel ratio is suddenly super lean.

Hope that makes a bit of sense and whilst there's a lot more to an engine running than just the TPS it's still an important part of making sure the car can adapt to what the driver is asking of it.

 

[Mel1978]

On 9/5/2019 at 10:50 AM, donthaveaford said:

I realize this is a super old thread but to clear up the confusion and maybe help anyone else trawling the web with a similar problem

What Dan62 is saying is slightly misleading

Yes the pedal is mechanically operated with a cable which in turn opens and closes the butterfly valve in the throttle body, in layman terms the sensor tells the ECU if the buttfly valve is open, closed or somewhere in between

So whilst the sensor won't be physically opening the valve it can still malfunction and send a signal to the ecu that isn't inline with what the butterfly valve is doing

For example: If the butterfly valve in the throttle body is all the way open but the sensor is telling the ECU the valve is closed the car may decrease the amount of fuel being injected into the engine to mix with what it believes is a very small amount of air the car will struggle to move under it's own power as the air fuel ratio is suddenly super lean.

Hope that makes a bit of sense and whilst there's a lot more to an engine running than just the TPS it's still an important part of making sure the car can adapt to what the driver is asking of it.

 

Hi can you help me my car fiesta 2093 1.25  says eac fail car revs on it’s own snd eobt drive changed pedal and  sonsor needs needs  throttle body all ones that are fit  the last 2 digits are not the sane mine says S6AU- DC they sat CC or AC  will this matter ? As I got by Ford they must match exact or car don’t run properly 
It’s only thing left to replace As I’ve cleaning it and putting back made no difference 😞