OBD-II trouble code
P2137: Throttle/Pedal Position Sensor 'B'/'C' Voltage Correlation
Throttle position sensors B and C disagree beyond tolerance — the redundancy cross-check failed, so the computer limits throttle authority.
Quick facts
- System
- Powertrain
- Category
- Throttle / Idle
- Severity
- High severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $100 – $650
- DIY difficulty
- Intermediate DIY
What does P2137 mean?
P2137 completes the throttle correlation family: sensors B and C — two of the redundant position signals in the electronic throttle system — have fallen out of their required voltage relationship. Together with P2135 (A/B) and P2136 (A/C), it tells you not just that a correlation failed but which pair, which helps triangulate: a sensor implicated by two pair-codes at once (say, C in both P2136 and P2137) is almost certainly the failed element.
The fault menu is identical to its siblings: a failing sensor inside the throttle body, connector corrosion skewing one signal, chafed wiring, carbon buildup causing uneven plate movement, or a sagging shared 5-volt reference. And the system response is the same firm one — reduced-power mode and capped throttle opening until the signals agree.
Graphing all throttle sensor voltages through a slow sweep is the decisive test. Most confirmed sensor failures end in throttle body replacement plus the relearn procedure, since individual sensors are rarely sold or serviceable.
Common causes
- Failing throttle position sensor (B or C) in the throttle body
- Corroded or loose connector terminals skewing one signal
- Chafed or shorted wiring between throttle body and PCM
- Carbon buildup causing uneven throttle plate movement
- Unstable shared 5-volt reference
- Water intrusion at the throttle body connector
Symptoms
- Check engine light with reduced-power warning
- Limp mode / capped acceleration
- Erratic, high, or hunting idle
- Hesitation or stalling
- Companion correlation codes (P2135/P2136) in many cases
Diagnostic steps
- 1.Note all correlation codes present — the sensor common to two pair-codes is the prime suspect.
- 2.Graph all throttle position sensor voltages through a slow sweep; identify which signal departs from spec.
- 3.Inspect the throttle body connector for corrosion, moisture, and terminal tension.
- 4.Check the shared 5-volt reference for stability, especially if unrelated sensor codes coexist.
- 5.Clean the throttle body if carbon-loaded and re-test correlation.
- 6.Replace the throttle body if a sensor is confirmed bad; perform the relearn and verify with a road test.
Repair cost
$100 – $650
Same repair economics as P2135/P2136: cleaning and connector work at the low end ($100-$200), throttle body replacement at $200-$600 installed plus relearn. Which pair-code you have doesn't change the cost — it changes which sensor you suspect first.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with throttle body cleaning preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.