What does fault code P0037 mean?
The P0037 fault code, applicable to all car manufacturers, means “HO2S Heater Control Circuit Low (Bank 1, Sensor 2)“.
Background Information: The oxygen sensor measures the oxygen content in the engine exhaust to correct fuel injection, thus achieving the optimal air-fuel ratio. In OBD fault codes, you’ll often see references to the oxygen sensor bank number. Bank 1 refers to the bank containing cylinder 1, and the remaining bank is Bank 2. Regardless of the bank, the first sensor always refers to the upstream oxygen sensor (before the catalytic converter), and the second sensor always refers to the downstream oxygen sensor (after the catalytic converter). The electronic control unit (ECU) maintains the oxygen sensor at 780°C by controlling the on/off state of the oxygen sensor heater. This fault code appears if the heater control circuit voltage falls below the calibrated minimum.
Symptoms of the P0037 error code (symptoms can be obvious or subtle):
- Engine malfunction indicator lamp illuminates
- Increased fuel consumption
- Weak engine response to accelerator pedal
- Instability during engine warm-up
- Problems passing emissions tests
Important! Sometimes the only symptom may be a burning engine malfunction indicator lamp. Therefore, regularly scanning the system for errors is crucial.
The main causes of the P0037 error code are:
- The oxygen sensor heating element is burnt out.
- An open or short circuit in the sensor wiring.
- A damaged oxygen sensor connector.
- A blown fuse in the heating circuit.
- An engine control unit malfunction (rare).
Possible causes and how to check?
| Possible causes | How to check? |
|---|---|
| Burnt heating element | Check the resistance between the heater contacts |
| Open circuit | Check for wiring damage |
| Short circuit | Check if the circuit is closed to ground |
| Damaged connector | Check the connector pins for corrosion or looseness |
| Electronic countermeasures failure | Diagnose using a scanner and check the output signal |
How to diagnose the P0037 error code?
- Step 1: Read the error code using an OBD2 scanner
- Step 2: Clear the fault code and perform a test drive
- Step 3: Check the resistance of the sensor heater (typically 5 to 14 ohms)
- Step 4: Check the wiring and connectors for damage and corrosion
- Step 5: Check the power supply to the heating element (12V during ignition)
Required tools:OBD2 scanner,Multimeter,Sensor removal kit,Vehicle wiring diagram (optional)
How to resolve P0037 error code? (Solution)
Simple solution
- Clear the error code and test the sensor
- Replace the damaged or old oxygen sensor
- Tighten or clean the connector contacts
In-depth diagnostics and repair
- Replace the wiring from the sensor to the control unit
- Check and replace the heating fuse
- Perform ECM diagnostics, replace if necessary