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Discussion Starter #1
Not long after I first got my RRS 4.2 S/C, just over a year ago, I started getting an occasional engine warning light illuminated, along with the code P2135 (Throttle/Pedal Position Sensor/Switch A / B Voltage Correlation). The car seemed to drive perfectly, but as the months progressed, the light started coming on more and more: I'd clear the codes and it'd come back the next day or the day after, for example.

I bought a brand new throttle body, thinking it would resolve it, but it made no difference. I then removed the trim under the driver's side kick panel and unplugged and replugged the throttle pedal connector, and if anything it seems to have made it worse: if I clear the code now, it comes back within only an hour or so. This could of course just be coincidence though.

The weirdest thing however is this: when I drive to the US from Mexico, where I live, the light still comes on, but nowhere near as often. I've been thinking about the reasons behind this and I've come up with the following three:

1) The gas I fill up with in the US is better than gas in Mexico. This seems unlikely though, as I fill up with 92 octane in both countries, and the fault doesn't seem to be a fuel related code.

2) When I fill up with gas in the US, I fill it up myself, whereas in Mexico an attendant does it. Perhaps I screw the gas cap back on better than they do, although this also seems unlikely as it happens virtually every time in Mexico, and the fault code doesn't seem to be related to the fuel / EVAP system.

3) When I drive to the US, I spend long periods on cruise control, where I'm not touching the accelerator pedal. Therefore, maybe the fault is in the pedal itself, and as I'm not pressing it anywhere near as much when I drive to the US, the fault appears far less. I feel like this is the most likely, but a lot of people have told me that when a P2135 code appears on these trucks, it's nothing to do with the accelerator pedal itself and must be within the throttle body. However, as I've changed the throttle body for a genuine part, this seems unlikely.

I get good gas mileage considering the type of vehicle, and the truck seems totally unaffected by the issue, other than the EML illuminating. I'd just like to get it sorted as when I sell the car in a few years, nobody will believe me when I say the EML genuinely doesn't affect it, therefore I'll get a lot less money for it.

So, any ideas / opinions on my theories?

Many thanks.
 

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Found this on the Web: Might help, but pretty sure it has nothing to do with gas quality or border involvement:


Quote:
What causes the 2135 code?



  • Faulty PCM
  • Faulty throttle position sensor(s)
  • Faulty accelerator position sensor
  • Disruption in the throttle position sensor circuit such as an open, corrosion, short, damaged wiring or broken electrical connections
  • Disruption in the accelerator pedal position sensor circuit such as an open, corrosion, poor electrical connection, short, damaged wiring or broken electrical connections
What are the symptoms of the P2135 code?


  • Surge or even possibly a hesitation when accelerating
  • Revving of the engine when gas pedal is not pressed
  • RPM’s are higher than usual
  • Check Engine Light illumination.End quote


Some ideas:

Check under the accelerator to assure nothing is keeping the sensor from measuring pedal position correctly. Clean the throttle bore and plate and check for ease of movement of the throttle plate; if this was a Jaguar, I would suggest checking for slack in the accelerator cable (not sure if the 4.2SC has a cable, so check for it). Turn the ignition to level two (ignition on, not start position: and depress the pedal ten to fifteen times -- cleans corrosion off the throttle position sensor); do a hard reset of the battery. Reset the OBD code and test it.
 

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Discussion Starter #4
Found this on the Web: Might help, but pretty sure it has nothing to do with gas quality or border involvement:


Quote:
What causes the 2135 code?




  • Faulty PCM
  • Faulty throttle position sensor(s)
  • Faulty accelerator position sensor
  • Disruption in the throttle position sensor circuit such as an open, corrosion, short, damaged wiring or broken electrical connections
  • Disruption in the accelerator pedal position sensor circuit such as an open, corrosion, poor electrical connection, short, damaged wiring or broken electrical connections
What are the symptoms of the P2135 code?



  • Surge or even possibly a hesitation when accelerating
  • Revving of the engine when gas pedal is not pressed
  • RPM’s are higher than usual
  • Check Engine Light illumination.End quote


Some ideas:

Check under the accelerator to assure nothing is keeping the sensor from measuring pedal position correctly. Clean the throttle bore and plate and check for ease of movement of the throttle plate; if this was a Jaguar, I would suggest checking for slack in the accelerator cable (not sure if the 4.2SC has a cable, so check for it). Turn the ignition to level two (ignition on, not start position: and depress the pedal ten to fifteen times -- cleans corrosion off the throttle position sensor); do a hard reset of the battery. Reset the OBD code and test it.
Thanks - I’ll try the ignition / pedal method and if that doesn’t sort it out I’ll get a new pedal assembly. As far as I’m aware, it doesn’t have a cable. I’ve already done the hard reset.
 

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Discussion Starter #5
Pleased to say that I finally fixed this. Turns out it was the electronics on the throttle pedal assembly: switched it with a $30 used one from a junkyard and no more EML.

Definitely worth trying that before going ahead and replacing the throttle body which is a much more expensive and complex job.
 
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