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Home / DTC / B1462 — Wide open throttle (WOT) position signal diesel engines

B1462 — Wide open throttle (WOT) position signal diesel engines

Detailed page for trouble code B1462.

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B1462

MERCEDES-BENZ B — Body

Wide open throttle (WOT) position signal diesel engines

Brand: MERCEDES-BENZ
Type: B — Body
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Page language: EN

Causes

  • Faulty accelerator pedal position sensor or WOT switch
  • Damaged, corroded or disconnected wiring or connector in the WOT/pedal circuit
  • Poor ground or loss of reference voltage to the sensor
  • Short to battery or short to ground on the signal circuit
  • Contamination, mechanical binding, or wear in the pedal/throttle assembly
  • ECM/PCM software fault or internal module failure

Symptoms

  • Malfunction indicator lamp (MIL) illuminated
  • Reduced engine power or limp-home mode (limited throttle response)
  • Poor or no full-throttle acceleration
  • Inconsistent or erratic throttle response
  • Stored freeze-frame data showing high or implausible pedal position

What to check

  • Scan for all stored and pending DTCs and record freeze-frame data
  • Check live-data for accelerator pedal position(s) and WOT status while operating the pedal
  • Visually inspect pedal assembly, connectors and harness for damage, corrosion or water ingress
  • Backprobe the sensor connector to verify reference voltage, signal voltage and ground
  • Perform a wiggle test on wiring and connectors while monitoring live data for intermittent changes
  • Compare outputs of redundant sensors (where fitted) for correlation

Signal parameters

  • Reference supply: typically a regulated 5 V reference to the sensor (verify with manufacturer data)
  • Idle pedal signal: commonly around 0.5–1.0 V (varies by design)
  • WOT pedal signal: commonly around 4.0–4.5 V at full travel (verify exact thresholds from OEM)
  • Dual-sensor systems: sensor A and B values should track closely; large deviation or inverse relation indicates sensor/circuit fault
  • Signal should be stable with key on/engine off; presence of full battery voltage on signal indicates short to 12 V

Diagnostic algorithm

  1. Read and record DTCs and freeze-frame data with a capable scan tool. Note related codes.
  2. Attempt to re-create the fault: clear codes, test with key on and while driving to observe live WOT/pedal position values and WOT switch status.
  3. Visually inspect pedal, harness routing, connectors and pin condition. Repair any damage or corrosion.
  4. With connector backprobed: verify the sensor has the correct reference voltage (≈5 V), a good ground, and measure the signal voltage while moving pedal from rest to full travel. Compare to expected ranges.
  5. If vehicle has dual sensors, compare both sensor outputs for proper correlation across the travel range. If sensors disagree, suspect sensor/module or wiring fault.
  6. Check for shorts: measure signal line voltage with key on engine off; disconnect sensor — signal should not have battery voltage. Check continuity to ECU and for short to ground/12 V.
  7. Perform wiggle tests on harnesses and connectors while monitoring live data for intermittent faults.
  8. If wiring and voltages are correct but signal remains out of range, replace the accelerator pedal module/WOT sensor per OEM procedure.
  9. After repair, clear codes, perform any required ECU adaptations or relearn procedures, and road test to confirm the fault does not return.
  10. If problem persists after sensor and harness replacement, consider ECU diagnostics or professional assistance following manufacturer diagnostic flowcharts.

Likely causes

  • Accelerator pedal module/WOT sensor failure
  • Damaged connector pins or water ingress at the pedal or wiring harness
  • Frayed or pinched wiring near pedal or bulkhead
  • Loss of 5V reference or poor sensor ground
  • Less likely: ECU internal fault or intermittent short

Fault status

⚠️ Status
ECM reports implausible/out-of-range wide-open-throttle (WOT) position signal on diesel engine — MIL set; throttle response may be limited.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.0 hours

Similar codes

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856

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