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2005 MERCURY MONTEREY
4.2L Essex OHV V6•AWD•gas
4 active safety recalls on this vehicle — view recalls
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Repairs0Labor507Torque136Fluid10DTC1798Battery1Maintenance0Recalls4
P0121high severityPowertrain

Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance

on 2005 Mercury Monterey 4.2L Essex OHV V6 · AWD

What this code means

The TPS signal does not match expected values for the current operating conditions.

Symptoms

  • Check Engine Light
  • Erratic throttle response
  • Stalling
  • Hesitation
  • Limp mode

Common causes

  • Worn TPS
  • Carbon buildup on throttle body
  • Sticking throttle plate
  • Loose throttle cable

Diagnostic steps

  1. Monitor TPS signal during throttle sweep
  2. Check for flat spots or dropouts
  3. Clean throttle body
  4. Inspect throttle cable/linkage

Repair notes

Clean throttle body. Replace TPS if signal is erratic.

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