The ECM has detected that the voltage signals from the two redundant sensor circuits “B” and “C” inside the Accelerator Pedal Position (APP) sensor (or the electronic throttle body) disagree beyond the calibrated tolerance. Because the sensors are designed to mirror each other for safety redundancy, any divergence triggers a correlation fault and usually forces the system into reduced-power “limp” mode to prevent unintended acceleration. The code indicates an electrical discrepancy rather than a mechanical throttle-plate issue.
Wear, contamination, or resistive-track degradation inside the pedal sensor causes circuits B and C to output voltages that no longer rise and fall proportionally, breaking the expected 2:1 or mirrored voltage relationship.
Chafed, pinched, or moisture-intruded wires create high-resistance paths, opens, or cross-talk between the 5-volt reference, signal, and ground lines for the B and C sensors.
Green/white corrosion, spread pins, or poor retention in the sensor or PCM connectors introduces voltage drop or intermittent opens that skew the signal correlation.
Physical obstruction, dirt, or broken return springs prevent smooth pedal travel, causing the two internal sensors to transition at different rates and generate divergent voltage curves.
Rare failure of the analog-to-digital converter or reference-voltage driver inside the control module misreads valid sensor inputs; should only be considered after the sensor and wiring are proven fault-free.
The vehicle will typically enter reduced power mode, making acceleration sluggish and limiting top speed; short trips to a repair facility are manageable, but highway driving or heavy traffic should be avoided until repaired.
No; P2137 refers to the correlation between sensor circuits B and C, which is almost always located in the accelerator pedal assembly or its wiring, not the throttle body actuator.
Almost never; the PCM is rarely the root cause. Most P2137 faults are resolved by replacing the pedal sensor or repairing wiring. Only consider the PCM after the sensor, connectors, and harness have been electrically tested and ruled out.
Cleaning the connector contacts may help if corrosion is present, but internal sensor drift or worn resistive tracks cannot be repaired with cleaner; replacement of the pedal sensor is usually required when the internal circuits fail to correlate.