Error code

OBD2 P0136

OBD2P0136
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

O2 Sensor Circuit.

Severity

moderateCan drive but may experience reduced performance and fuel economy.

Summary

P0136 indicates a malfunction in the heated oxygen sensor (HO2S) circuit for Bank 1 Sensor 2. This sensor monitors the catalytic converter's efficiency.

Symptoms

  • Stored trouble code
  • Rich or lean running conditions
  • Reduced fuel economy
  • Engine hesitation or stumbling upon acceleration
  • Rough idling

Common Causes

  • Damaged, burnt, shorted, disconnected, or corroded wiring and/or connectors
  • Heavily fouled or contaminated oxygen sensors
  • Defective oxygen sensor
  • PCM failure (rare)

Diagnosis

  1. Check for other air/fuel metering codes and resolve them first.
  2. Inspect wiring and connectors for damage or corrosion.
  3. Monitor sensor temperature and signal voltage using a scanner.
  4. Perform resistance, ground, continuity tests on the wiring.
  5. Test oxygen sensor resistance and inspect it for contamination.

Fixes

  • Replace damaged wiring and connectors as needed.
  • Clean or replace heavily fouled oxygen sensors.
  • Replace the defective oxygen sensor if necessary.

FAQ

What causes oil fouling of oxygen sensors?

High oil consumption rates, especially in vehicles like BMW, Audi, VW, and Mercedes-Benz.

How do I prevent future issues with the oxygen sensor circuit?

Ensure proper routing and securing of wiring away from hot exhaust components. Regularly inspect sensors for contamination or damage.

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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