Heated Oxygen Sensor Circuit Malfunction Bank 1 Sensor 2
Table of contents
P0136 Possible Causes
- Exhaust gas leaks
- Faulty Heated Oxygen Sensor 2 (HO2S2) (Downstream) Bank 1
- Heated Oxygen Sensor 2 Bank 1 harness is open or shorted
- Heated Oxygen Sensor 2 Bank 1 circuit poor electrical connection
- Inappropriate fuel pressure
- Faulty fuel injectors
How do I fix code P0136?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Cost of diagnosing the P0136 code
The cost of diagnosing the P0136 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- High Fuel Consumption
P0136 Description
The Heated Oxygen Sensor 2 (HO2S2) (Downstream), after the three-way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. For optimum catalyst operation, the air-fuel mixture (air-fuel ratio) must maintain near the ideal stoichiometric ratio. The HO2S2 output voltage changes suddenly in the vicinity of the stoichiometric ratio. The Powertrain Control Module (PCM) adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The HO2S2 generates a voltage between 0.1 and 0.9 V in response to oxygen in the exhaust gas. If the oxygen in the exhaust gas increases, the air-fuel ratio becomes Lean. The PCM interprets Lean when the HO2S2 voltage is below 0.45 V. If the oxygen in the exhaust gas decreases, the air-fuel ratio becomes Rich. The PCM interprets Rich when the HO2S2 voltage is above 0.45 V. The P0136 code will set when the PCM detects that the HO2S2 signal voltage is out of range for an extended period.