Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Changing throttle pedal sensor on 3.7 Roadster

As part of my troubleshooting with very intermittent severe misfiring and throttle response I'm now left with changing components in the DBW system. This following consistent P2135 fault code (Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation). This translates as fault in either throttle position sensor or throttle body. The latter has been removed and cleaned with no improvement. Current thoughts are that short term fuel trim held in volatile memory of ECU gets trashed causing this issue, currently around every 200 - 300 miles, as a three minute wait with ignition off restores engine to perfectly normal running again.

Chasing part numbers of these two components revealed that Melvin Rutter was able to obtain the throttle pedal sensor under their heritage parts scheme with 25% discount hence just over £100 delivered. The presumably ex 2011-14 Mustang 3.7 V6 part arrived as below with all plastic pedal and perfect Ford number match to OE.



I just need to use hacksaw, drill and Dremel to change it to this, noting that Morgan's steel pedal is bolted at right angles to plastic pedal stub.



Well they do say Morgan's are hand made

Hi Richard

Sorry to hear you still have the problem hope your new throttle pedal and position sensor resolves your misfiring issue. If not, next time you get the P2135 fault code, before you clear it, it might be worth looking at the freeze frame data that will have been stored when the fault occurred and the code was generated. It takes a bit of studying but does give you a lot of useful information about the state of things at the time of the misfire, one of which should be the short term fuel trim value.

Regards Tony

Fingers crossed that cures it Richard

Would be interesting to see the condition of the potentiometer inside the old unit ?

Well done Richard for getting into that area to take it off & replace it. How is the back?

Not too bad John just bruised arms. New sensor suitably hacked now and ready to re-fit. Would have been happier changing throttle body but only ones I've seen are secondhand from Romania. MR don't have any available.

Thanks for suggestion Tony but not sure how to view/download freeze frame data using TorquePro app on my phone. Only historic data seems to be positions from last drive.

Update for Tony - just found how to access freeze frame data so will try to view next time I get fault code (if new pedal sensor doesn't cure). To be fair the fault code description is quite specific although having only two channel system doesn't allow diagnosis of which end of DBW system the fault lies.

Excellent Richard well done. Always worth a look at with any fault code and as no doubt you will have deduced as soon as you clear the code the freeze frame data is dumped.
Regards Tony

New position sensor back in after some delay getting all three mountings screws back in. Longer arms and less shaky hand would have helped . Plugged new unit back into loom and before final button up checked via OBD2 hookup that pedal operated throttle. Much joy when it did, opening to its reported maximum of 75% as before. Cable tied sensor cable as little higher to reduce possibility of throttle foot disturbing it, given MMC modified orientation.

Interesting to note replacement sensor, according to moulding marks, was from same batch as OE on my 2018 car showing made in November 2017. Likely only 50/50 chance at best this will fix the issue but just going through the motions now.

Fingers crossed for you Richard

Well done and Good luck Richard hope it does the job, you deserve it to after scrabbling down in the footwell. I know from experience not a pleasant easy job


Tony