P2139: Throttle/Pedal Position Sensor/Switch D/F Voltage Correlation

What does P2139 mean?

P2139 compares signals D and F, in practice the first and third tracks of a three-track accelerator pedal. No manufacturer publishes a detection rule for this exact code; FCA only lists P2139 in emissions recall T21 for the 2004-2006 Dodge Sprinter among codes that can appear after the ECU update. Makers with three-track pedals handle the comparison differently: GM's 2004-2005 trucks scale sensor 3 and test it against sensors 1 and 2 at 0.26 V, then blame the odd track through P2131 or P2126 instead of naming a pair, and Ford reports a deviating track F as P2131. A pair code like P2139 cannot say which of the two tracks is wrong, so check both with a scope while moving the pedal. Effects are a warning lamp and softened acceleration.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Engine or wrench warning lamp on
• Softened or delayed acceleration

Common causes

• High Track D or F of the pedal sensor worn or drifted
• Medium Contact resistance at the pedal connector
• Low Fault on a shared ground or 5 V reference

Likelihood is a general estimate across vehicles; your make and model may differ.