What is the P0038 fault number? What is the description of Heated Oxygen Sensor Heater Circuit High (Bank 1 Sensor 2)? How can I fix P0038 fault code What are the causes and symptoms for the P0038 fault code
What is the P0038 fault code? What does it signify?
An oxygen sensor measures the amount of oxygen in exhaust gas. This information is sent to the powertrain control modules (PCM/ECM). This information allows the PCM adjust the fuel and air mixture to maximize engine performance.
In order for oxygen sensors to work accurately and accurately, they need to be at a certain temperature. The measurements you take will not be correct if the engine is still cold when you first start your vehicle. The PCM will ignore data from oxygen sensors until the engine heats up. This problem is solved by heated oxygen sensors, which heat up quicker than regular sensors.
The number 2 oxygen sensor is located after the catalyst. It is used primarily to monitor the efficiency and performance of the catalytic convertor. Bank 1 refers the side with the number 1 piston.
Heater elements are a part of all heated oxygen sensors (HO2S). They help the sensor reach its operating temperature quickly. Pre-OBD II oxygen sensors are typically single-wire. O2 sensors that are post OBD II are usually four-wire. Two wires are for the oxygen sensor, and two wires are for the heating element. The O2 sensor heater reduces the time it takes for the engine’s to enter closed loop. The PCM continuously monitors the heater for abnormal voltage signals. The fault code P0038 is set if the PCM detects an unusually high voltage signal within the heater circuit for more than 8 seconds. The oxygen sensor’s resistance will be 8 Ohms, or very close to this value. Any deviations of 10% from this value will cause code P0038. All oxygen sensors require that the input voltage to their heater control circuits must be equal or greater than the battery voltage. The P0038 fault code will still be set if there is a 10% deviation.
NOTE: Some Japanese cars like Toyota do not use conventional oxygen sensors. It uses non-replaceable fuel ratio (AFR), sensors. For correct test/diagnosis/repair procedures, refer to the relevant repair manual.
What causes the P0038 Fault code?
Overvoltage can often cause high voltage signals. Sometimes, short circuits like cable leaks can cause high voltage signals. Check for other codes, even if they seem unrelated. Before you attempt to fix the problem, make sure to thoroughly test the charging system.
- – Defective oxygen sensor (sensor 2)
- – O2 sensor circuit problems (open, or shorted).
- – Don’t place fuse wires too close or exhaust components
- – Broken or loose connections
- – If applicable, blown O2 sensor heater circuit fuse
- – Defective PCM (rarely)
What are the symptoms for P0038 fault code?
- – Illumination for the check engine light
- – Good working conditions
- – Poor working conditions
- – Increased fuel use
- – Engine losing power
- – Idle irregularity
- – The exhaust emits black smoke
- – Rarely, hard starting the engine
How to Fix the P0038 Fault Code
First, visually inspect the heated oxygen sensor (and the wiring harness) that connects to the catalyst in the first row. Repair as necessary if the sensor is damaged or the wiring is damaged. You should inspect for exposed wires at the sensors. This can cause weak signals or short circuits. It is important to avoid letting the wires touch the exhaust. If necessary, repair or replace the sensor.
If all is well, disconnect the sensor from the power supply and test for 12 volts of current with the ignition off. Verify that the heater circuit’s ground circuit is not damaged. If the problem is not obvious, you can remove the O2 sensor to check for damage. You can test the resistance of your heater element using an Ohmmeter if you have access the resistor specifications. A heater with an inexorable resistance is considered to be open. If necessary, replace the O2 sensor.
