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
الأسباب المحتملة
Possible Symptoms
Engine Light ON (or Service Engine Soon Warning Light)
High Fuel Consumption
الأعراض المحتملة
Description
Code P0136 BMW 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.
P0136 BMW Code – Heated Oxygen Sensor Circuit Malfunction Bank 1 Sensor 2
