P1186 BMW, MINI: O2 SENSOR HEATER CONTROL CIRCUIT BANK 1 SENSOR 2
POST UPDATED IN May, 2023
P1186 Code failures by brands
Description of DTC code P1186
An HO2S (Oxygen Sensor) is an essential component of the combustion system. Its function is to measure the amount of oxygen in the exhaust. Then, this sensor provides this data to the Powertrain Control Module (PCM). The PCM uses the information received by the PCM to adjust the air-fuel mixture as required to ensure optimum engine performance.
The oxygen sensor’s accurate readings are highly dependent on its temperature. For this reason, a heating element is incorporated into these sensors, which significantly reduces the time it takes for the sensor to reach this temperature.
The PCM continuously checks the performance of the oxygen sensor to verify if the oxygen sensor parameters are within the appropriate levels. If a malfunction is detected in the circuit controlling the heater of the O2 Sensor number 2 of bank 1, the diagnostic code P1186 OBDII will be set.
Symptoms of fault code P1186
- Check Engine light illuminated.
- Improper engine performance.
Causes of OBD2 P1186
Reasons to set the P1186 OBD2 fault code:
- Engine may be leaking exhaust air.
- Bank 1 HO2S 2 circuit wires or connectors may be faulty.
- Oxygen Sensor 2 heater circuit could be open or shorted.
- HO2S 2 bank 1 could be faulty.
Possible solutions of the DTC code P1186
To troubleshoot the DTC P1186 OBDII, try this:
- First, consult the Technical Service Bulletins.
- Check the exhaust system for leaks. If such conditions are found, make the appropriate repairs.
- Check all the wiring and connectors related to the Oxygen Sensor. If you discover corrosion, burns, or wear, make the necessary corrections.
- Check that the HO2S voltages are within the range determined for proper performance. These tests should be performed with the engine at operating temperature. If some differences are detected, make adjustments, including the sensor replacement.
