P2137

Throttle/Pedal Pos Sensor/Switch B / C Voltage Correlation

P2137 is a generic OBD-II powertrain diagnostic trouble code: Throttle/Pedal Pos Sensor/Switch B / C Voltage Correlation. It is logged by the engine control unit when the throttle monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P2137
Group
Powertrain
System
Throttle
Severity
Warning (MIL on, possible limp mode)
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What P2137 means

P2137 is set when the PCM detects that throttle or pedal position sensor circuits B and C produce voltage signals that do not correlate within the defined tolerance. Like P2135 and P2136, this code is part of the ETC system redundancy verification logic that continuously cross-checks multiple sensor channels to detect single-point failures.

The B and C channels may each be within their individual range limits, yet fail the correlation check if the mathematical relationship between them deviates beyond calibrated thresholds. This approach allows the PCM to detect subtle sensor degradation that would not be caught by simple range monitoring alone.

Diagnosis should focus on live data comparison of both channels across a full controlled sweep, combined with careful inspection of the sensor wiring harness and connectors. Because the B and C designation is manufacturer-specific in its physical assignment, a wiring diagram for the specific vehicle is essential to correctly identify which circuits to test.

Common causes

Most-frequently reported root causes when P2137 is logged.

  • 1
    Sensor track B or C internally degraded, drifting, or intermittently open.
  • 2
    Open or high-resistance circuit on the B or C signal wire.
  • 3
    Short circuit on one signal line affecting its voltage level.
  • 4
    Connector pin damage, corrosion, or terminal spread on the B or C circuit.
  • 5
    Sensor supply voltage variation affecting one channel disproportionately.
  • 6
    Contamination or moisture ingress into the sensor body.
  • 7
    Incorrect or non-OEM replacement sensor with different transfer characteristics.

Symptoms drivers notice

MIL on with possible limp-home or reduced power mode.
Inconsistent or sluggish throttle response.
Idle instability in some cases.
May be accompanied by other ETC sensor correlation or range codes.
Intermittent fault possible, worsening under temperature or vibration stress.

How to diagnose P2137

A typical diagnostic flow when this code is present.

  1. 1
    Scan for all DTCs and document freeze frame data.
  2. 2
    Monitor sensor B and sensor C live data values simultaneously through a full pedal or throttle sweep.
  3. 3
    Confirm the expected correlation relationship and note where deviation occurs.
  4. 4
    Use a wiring diagram to identify the physical B and C circuit pins at the sensor connector.
  5. 5
    Inspect the connector and harness for damage, corrosion, or moisture intrusion.
  6. 6
    Measure reference voltage and ground quality at the sensor connector.
  7. 7
    Replace the sensor if circuit checks are normal, then relearn and retest.

Related powertrain codes

Frequently asked questions

What is the difference between P2136 and P2137?

P2136 monitors the correlation between channels A and C, while P2137 monitors channels B and C. Both indicate a breakdown in the expected relationship between a specific sensor pair.

Can both P2136 and P2137 set at the same time?

Yes. If a single sensor track (for example track C) is at fault, it can simultaneously cause both the A/C and B/C correlation checks to fail, setting both codes.

Does the engine shut off with P2137?

Typically no, but the PCM will activate a failsafe mode that may limit throttle response or cap engine speed. Complete shutdown is uncommon unless additional critical faults are also present.

How do I know which sensor to replace?

Live data comparison across all channels helps identify which specific track is diverging. The channel that is inconsistent relative to both others is the most likely failure point.

Disabling P2137 in software

RaceTune can permanently disable P2137 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

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