Fehler P0138 – wie beheben?

Code Definition P0138

O2 Sensor Circuit High Voltage (Bank 1, Sensor 2)

What does code P0138 mean?

P0138 is a generic OBD-II code indicating that the O2 sensor in Bank 1, Sensor 2 has an output voltage not lower than 1.2 V for more than 10 seconds, which indicates a lack of oxygen in the exhaust gas stream.

What causes code P0138?

• The Engine Control Module (ECM) detects that the O2 sensor voltage for bank 1 sensor 2 is higher than 1.2 V when the ECM requests fuel to achieve a target lean condition on that engine bank.
• The ECM detects a high voltage problem and illuminates the check engine light.
• The ECM uses other O2 sensors to attempt to control fuel injection using their values.

What are the symptoms of code P0138?

• The engine may run at low RPMs during sensor testing to correct the problem and may misfire or shut off.
• The check engine light illuminates.
• Depending on the cause of the fault, engine running problems may occur due to a rich condition.

How does a mechanic diagnose code P0138?

• Scans codes and documents freeze frame data, then clears codes to verify the fault.
• Monitors O2 sensor data to see if the voltage changes rapidly between low and high levels compared to other sensors.
• Checks O2 sensor wiring and wiring connections for corrosion in the connections.
• Checks the O2 sensor for physical damage and contamination by fluids.
• Checks for exhaust leaks before the sensor.
• Perform manufacturer-recommended tests for further diagnosis.

Most common mistakes when diagnosing code P0138

• Follow these simple instructions to avoid misdiagnoses:
• O2 sensor 1 for bank 1 can be used to diagnose O2 sensor 2 for bank 1 by observing the operation of both sensors for comparison. The operation should be almost identical, except that sensor 2 should have a lower O2 reading because the catalytic converter must burn off excess fuel and oxygen.
• Check the O2 sensor for oil or coolant contamination due to any engine leaks.
• Check if the catalytic converter is damaged or clogged, which could cause incorrect readings from the sensors.

How serious is code P0138?

• The O2 sensor output voltage can be caused by a damaged exhaust catalytic converter, which can cause high output voltage from the O2 sensors.
• The ECM may not properly control the engine’s air-fuel ratio, leading to a clogged catalytic converter and excessive carbon buildup in the engine with dirty spark plugs.

What repairs can resolve code P0138?

1. Replacing the O2 sensor in bank 1 sensor 2.
2. Repairing or replacing the wiring or connection to the O2 sensor for bank 1 sensor 2.
3. Replacing the catalytic converter before the sensor.
4. Repairing a faulty injector.

Further notes on code P0138

A high O2 sensor voltage condition indicates a lack of oxygen in the exhaust gases or other related problems, such as a faulty fuel injector or a damaged catalytic converter inside.

About Error P0138 – how to solve it?

The car model that often faces the P0138 error is known for its reliability and performance. This car is equipped with modern engines that provide efficient fuel consumption and sufficient power for everyday driving. The engines are designed to meet emission standards while providing smooth operation. The model is popular among drivers looking for a combination of comfort and technology. The P0138 error usually relates to problems with the oxygen sensor, which can affect engine performance and fuel consumption.

Fuse box diagram Error P0138 – how to solve it?

This page shows the fuse box diagram for solving the P0138 error. In a typical car model, the fuse box is located under the dashboard or in the engine compartment. The diagrams on this page show fuse numbers, their amperage values, and the components they protect. It is important to always use replacement fuses with the same amperage value to prevent damage to electrical systems. The fuse box is a key element for the proper functioning of electrical components, and its correct use can help prevent problems such as the P0138 error.