3200 Throttle Pedal Sensor

[Oneball]

I’ve replaced my throttle pedal sensor with one from Davy and am still getting a throttle pedal sensor fault code. Upon closer examination of the wiring there are two grey wires on the loom side of the connector that seem to have been detached. I’ve got a workshop manual but the wiring diagram doesn’t quite tie with what I’ve got in front of me. Does anyone know where they’re supposed to be?

 

[alfatwo]

I've just changed mine for an original Bosch, the wiring loom didn't like that
I suspect someone's been in the fiddling before you..

Dave

 

[Oneball]

Thanks Dave, that’ll explain why it doesn’t quite tally with the workshop manual.

More grovelling in the footwell required!

 

[alfatwo]

Thanks Dave, that’ll explain why it doesn’t quite tally with the workshop manual.

More grovelling in the footwell required!

If you look carefully, is it possible to work out where those gray wires were connected on the multi plug, before they were cut off

Dave

 

[Oneball]

No. There’s no evidence of any cut wires in the connector itself. I don’t know whether they’ve been replaced by the other two grey wires which are on a separate loom. Need to pull the carpet out to see where they all go.

 

[davy83]

I think your car has had the ground rework done to it, my car is the same. I don't think the two extra wires are your problem sir. If you look all six connections in the connector are connected so there are not two wires missing.
on the fitting of the new sensor, did you check the voltages were correct? How many times have you run the calibration?

 

[Oneball]

Thanks.

When I fitted the sensor I adjusted the idle position to give 0.35v and then adjusted the pedal stop to give 3.3v.

I’ve run the calibration once.

 

[davy83]

Did the CEL ever go out or do you get an error every time it starts up? Did you try pressing the throttle pedal down a few times with the meter connected to make sure the pedal always goes back to the same position? Its quite fussy about this. Also check the two outputs are both the same and both within the limits (you have one of my new design sensors so this really should not be an issue), note the lower limit on the voltage is 0.35 volts I think so it might be worth adjusting that up a little before trying again? If all that is ok I would be tempted to try the calibration again, maybe more than once, make sure the timing is correct, add a few extra seconds to make sure. Sadly there is no way to know the calibration has been accepted by the ECU other than the yellow light goes out!

 

[Oneball]

CEL is permanent.

The P0225 error is always present and returns as soon as you clear it. But the other two errors, P1225 & P1226 have gone. It has a contactless throttle body already.

I moved the pedal a few times to check max and min and they fell within the range.

Will check voltages on both wires, try calibration and adjust again tomorrow.

Thanks for your help.

 

[Contigo]

Leave ignition on for ten mins turn it off. The ignition to MAR and foot to floor for 10 seconds then start after releasing pedal. Repeat...

 

[davy83]

The fact the error comes on straight away suggests it does not like the situation at power up. So I think increase the 0.35 volts to at least 0.37 remember you can go up to 0.65. And run the calibration twice just in case and you should be ok.

 

[Oneball]

Thanks. I’ll check the voltage and continuity across both circuits and if they’re ok I’ll adjust it up a bit.

Autoshield have told me that the “two grey wires” are a Maserati fix and a bit of googling seems to suggest they bypass the loom and a couple of connectors and end up in the same place as the originals.

 

[dunnah01]

Is it just the bodge that some people have done to prevent a CEL from the voltage of the two sensor tracks being different as they wear. There are two independent circuits as a safety measure to failsafe if one circuit goes a bit wonky. As the pot tracks wear the voltage difference can be too high and the CEL is thrown as a safety measure. A workaround is to chop the wire to one circuit so there is no measured voltage. Not the safest solution but it apparently works as a short term fix. It could just be a case of re-connecting the grey wires back together to give your new pot both the circuits it is looking for.

 

[Oneball]

Is it just the bodge that some people have done to prevent a CEL from the voltage of the two sensor tracks being different as they wear. There are two independent circuits as a safety measure to failsafe if one circuit goes a bit wonky. As the pot tracks wear the voltage difference can be too high and the CEL is thrown as a safety measure. A workaround is to chop the wire to one circuit so there is no measured voltage. Not the safest solution but it apparently works as a short term fix. It could just be a case of re-connecting the grey wires back together to give your new pot both the circuits it is looking for.

No, that’s done by connecting the yellow and white wire. This just seems to make the route shorter and removes a connector. I’m guessing it’s to cure an interference or continuity fault.

 

[Contigo]

Correct an earthing issue iirc.

 

[Oneball]

The fact the error comes on straight away suggests it does not like the situation at power up. So I think increase the 0.35 volts to at least 0.37 remember you can go up to 0.65. And run the calibration twice just in case and you should be ok.

I've increased the idle voltage to 0.38v and done the calibration, error has gone and hasn't come back yet, will go to Curborough at the weekend in it so fingers crossed.

Thanks all for your help.

Tim

 

[davy83]

excellent!! Hope that's the last time you see that error! enjoy sir.

 

[urquattrogus]

My car had the two grey wires tied back like that too. Same thing, the ground re-work etc - also presumed the same as you to begin with!