Engine-Codes - Mazda - P0037 Mazda

P0037 Mazda Code - HO2S Heater Control Circuit Low 12

- Code Popularity: 65,466 Views
- Repair Importance Level: 2/3
- Repair Difficulty Level: 2/3
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What are the Possible Causes of the DTC P0037 Mazda?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2
  • Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 fuse
  • Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 harness is open or shorted
  • Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 circuit poor electrical connection
  • Faulty Engine Control Module (ECM)

Code Tech Notes

The code means that there is a problem with the heater element circuit of the heated oxygen sensor. Water getting inside the heated oxygen sensor connector can caused the heated oxygen sensor fuse to blow, which is a very common problem for this type codes. Before replacing the sensor, check for the condition of the heated oxygen sensor fuse and connectors.

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How to Fix the DTC P0037 Mazda?

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 pins.

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What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the P0037 Mazda code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

When is the Code Detected?

The P0037 is set when the ECM detects an excessively low voltage through the heated oxygen sensor heater circuit

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

What Does the P0037 Mazda Code Mean?

Oxygen Sensors (O2S) or Heated Oxygen Sensors (HO2S) need to reach a minimum operating temperature of 750 degrees F to produce an accurate voltage signal. The faster the heated oxygen sensor reaches that temperature the faster the sensor will start sending an accurate signal to the Engine Control Module (ECM).
In order to achieve the require temperature, a heater element is included inside the heated oxygen sensor. The ECM controls the heated oxygen sensor heater element based on signals from the engine coolant temperature and engine load. The ECM controls the heater element circuit by allowing current flow to ground.
The ECM monitors the voltage signal received through the heater element circuit and determines the state of the circuit by comparing the voltage detected with the factory specifications.
P0037 Mazda Code - HO2S Heater Control Circuit Low 12

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