Code P0032: Oxygen (A/F) Sensor Heater Control Circuit High (Bank 1 Sensor 1)

You’re driving along and suddenly your dashboard lights up with the check engine light. After using an OBD-II scanner, you find that the problem is code P0032. So, you are left asking: what does the code P0032 mean? Why did this happen? How do I fix trouble code P0032?

What Does the Code P0032 Mean?

P0032 is a generic powertrain diagnostic trouble code (DTC) that can appear on all OBD-II equipped vehicles. Any vehicle sold after 1996 in the United States has an OBD-II system.

This code related to the O2 sensor located on bank one in sensor position one. Bank one is the engine bank that contains cylinder one. O2 sensor one is located in front of the catalytic converter. For reference, sensor two is located behind the converter.

The O2 sensor detects the amount of oxygen in the exhaust gas and compares it to the amount of oxygen in the outside air. Using this data, the vehicle’s computer can adjust the fuel-air mixture being sucked into the engine.

O2 sensors are more effective with warmer exhaust gas. So, to facilitate this process, the sensor has a connected heater. Code P0032 means that the heater circuit resistance is above its tolerance range. The allowable range varies from vehicle to vehicle; however, the upper limit is 10A in many vehicles.

What Are the Symptoms of Code P0032?

This code relates to a heater than assists an exhaust oxygen sensor. Therefore, it is very unlikely to have any noticeable symptoms other than the check engine light and the code. You may notice some fuel efficiency and/or power loss due to a sub-optimal fuel-air mixture. However, this symptom is likely to be undetectable except in extreme circumstances.

What Are the Causes of Code P0032?

Typically, the OBD-II scanner error code P0032 problem is an electrical one. These are a few of the possible causes of this trouble code:

  • The wring or electrical connectors between the sensor and relay are damaged.
  • The O2 sensor heater is faulty.
  • There is a short or open circuit in the O2 sensor heater wiring.
  • The powertrain control module/engine control module is faulty.

The last of these is an unlikely problem. However, vehicles’ PCMs or ECMs can sometimes set codes incorrectly.

How Do I Fix Trouble Code P0032?

Start troubleshooting the cause of the code by inspecting the wiring and connections on the O2 sensor heater. Look for any wires that are frayed, broken or otherwise seem to be damaged. If there are a heater relay and fuse, inspect that as well for a blown fuse or any damage.

If you find any damage, repair it or replace the component. Following this, capture the freeze frame data from your OBD-II scanner then reset the codes. Run your vehicle and see if the code returns.

If there was no noticeable damage or if the code returned, get a multimeter and check the circuits. Measure the voltage of the heater circuit. Then, check the ground circuit for continuity. Check the resistance of the heater circuit. Finally, measure the resistance and voltage of all the related wiring.

You will need to check your vehicle’s service manual for specific instructions for checking electrical values. Different makes and models have their own allowable ranges for resistance and voltage.

If you discover an out of range value, repair or replace the component. Then, clear the codes as described above and check to see if it returns.

Replace the O2 sensor if needed. This is often the fix for this code. Ideally, use an OEM sensor as many aftermarket alternatives are of lower quality. Before making a replacement, check your warranty information. The sensor may fall under a federal emissions warranty.

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