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P0052 Fault Code (Causes & Fixes) HO2S Heater Control Circuit Low (Bank 1, Sensor 2)

Updated: Jan 9

The "HO2S Heater Control Circuit High (Bank 2 Sensor 1)" OBD code P0052 is produced when the Engine Control Module (ECM) detects a signal voltage from oxygen sensor 2 that is not within the specified range.


If a DTC is associated to the powertrain, an OBD scanner will read it as starting with P, thus the letter "P". Generic fault codes are those of the format P0xxx.
 

Table of Contents:

 

The Meaning of a P0052 Fault Code

When the Engine Control Module (ECM) attempts to control the heater control circuit for Bank 2 Sensor 1 and detects high voltage, the P0052 code is generated.


The engine must have an ideal air-fuel ratio of 14.7 to 1 in order to function properly, and the HO2S (oxygen sensor) analyses the oxygen level of the exhaust to ensure this air-fuel ratio is met.


It is heated to ensure that the PCM reacts fast to the closed-loop system, thereby reducing emissions at startup.


When there is an issue with the HO2S heating element, in this case too high a voltage, the error code P0052 occurs.


Is It Serious?

This code is rated as minor-to-moderate. Because the HO2S has such a little influence in how a vehicle operates, there are usually few driveability symptoms.


As a result, the vehicle may be driven, but it should be taken in for diagnostic and repair as soon as possible to avoid future issues like the ones described below.


  • poor performance

  • lower fuel efficiency

  • sensor loop failure

  • damage to other components


Signs & Symptoms of P0052

Unlike in many instances where OBD error codes are generated, the P0052 has few signs and symptoms associated with it. Though, there may be a few indicators that you could notice.


You may notice the following signs:

  • Check engine light (CEL) illumination

  • Poor performance and drivability

  • Lower fuel efficiency


Possible Causes of a P0052 Fault Code

There are several potential causes for the P0052 error code, but the following are the most common.


  • Engine bank HO2S sensor failure 2

  • Exhaust ground connection that is corroded

  • Faulty PCM sensors

  • Faulty wiring to the oxygen sensor (HO2S)

  • Water penetration causing the HO2S fuse to fail


Diagnosing the P0052 Trouble Code

Diagnosing this fault code is best done using a professional OBD scanner or by completing a diagnostic check with a skilled technician.


Many vehicles with over 80,000-100,000 miles have sensor faults that arise during start-up or sustained driving.


  1. Check to see if there are any technical service bulletins available for your vehicle's model and make sure to see if there is a known problem with your vehicle that may help you in resolving the issue.

  2. Scan your system for any more OBD fault codes. If any of these are present, they should be investigated also.

  3. Clear the error codes before driving the vehicle while an OBD scanner scans the live data.

  4. If the issue continues, examine the wiring for broken or loose connections.

  5. Examine the power and ground connections on the sensor.

  6. Examine the HO2S heating element.


Testing the Wiring

Check for a fused battery supply to the heating element of 12+ volts using a digital voltmeter with the key on and the engine off. If no voltage is available, repair any open or short circuits in the 12 volt supply, but first check to see if any blown fuses are the result of the short.


Disconnect the ground (control) circuit from the ECM wire connection if the battery feed is ok, then test the circuit for resistance. If there is infinite resistance, repair the open in the circuit.


Possible Fixes for a P0052 Code

It is advised that you test drive the car after each fix to determine whether the fault code is resolved. If the code reappears, try the next repair option.


Common fixes for a P0052 error code you should try are to:

  1. Reset the trouble code after verifying the code using a professional OBD reader. After that, do a test drive to determine whether the issue code has been cleared.

  2. If the code appears, check voltage and ground and repair or replace any loose or faulty wiring to the HO2S.

  3. If this does not fix the problem, the HO2S should be replaced.