Error code

OBD2 P0140

OBD2P0140
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

O2 Sensor Circuit No Activity Detected.

Severity

highThe vehicle may be drivable but with significant performance issues.

Summary

Code P0140 indicates that the heated oxygen sensor (HO2S) on bank 1, sensor 2 is not sending any signal voltage to the PCM. This can affect fuel efficiency and engine performance.

Symptoms

  • Severe driveability issues such as loss of power, hesitation upon acceleration, and unexpected stalling
  • Increased fuel consumption
  • Visible black smoke from the tailpipe
  • Hard starting
  • Oil dilution due to over-fueling
  • Reduced spark plug life

Common Causes

  • Defective oxygen sensor
  • Damage to wiring in the heater control circuit delaying heating time
  • Blown fuse(s) preventing the element from heating up
  • Faulty PCM (rare)

Diagnosis

  1. Check for other stored trouble codes and freeze frame data.
  2. Inspect wiring associated with the affected sensor for damage.
  3. Perform resistance, input voltage, ground, and continuity checks on all circuits.
  4. Remove and inspect the oxygen sensor for discoloration or deposits.

Fixes

  • Replace the defective oxygen sensor if it shows no activity or is damaged.

FAQ

What does P0140 mean?

P0140 indicates that the heated oxygen sensor (HO2S) on bank 1, sensor 2 is not sending any signal voltage to the PCM.

How do I fix P0140?

Fixing P0140 typically involves replacing a defective oxygen sensor or repairing damaged wiring in the heater control circuit.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

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