P0138 – O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
Encountering the P0138 code in your Geely? Here is a complete guide to its causes, symptoms, and solutions.
WHAT DOES CODE P0138 MEAN
The P0138 error code is defined as an O2 Sensor Circuit High Voltage (Bank 1 Sensor 2) issue. This code indicates that the engine control module (ECM) has detected a voltage reading from the oxygen sensor that is higher than expected. The oxygen sensor is responsible for monitoring the amount of oxygen in the exhaust gas and providing this information to the ECM, which uses it to adjust the fuel-to-air ratio. When the ECM detects a high voltage reading from the oxygen sensor, it may indicate a problem with the sensor itself or the wiring circuit.
COMMON Geely MODELS AFFECTED
- Geely Emgrand EC7
- Geely Emgrand EC8
- Geely GC2
- Geely GC5
- Geely MK
SYMPTOMS TABLE
| Symptom | Frequency of Occurrence |
|---|---|
| Check Engine Light (CEL) illumination | High |
| Poor fuel economy | Medium |
| Rough engine idle | Medium |
| Decreased engine performance | Medium |
| Failed emissions test | Low |
| Engine stalling or hesitation | Individual |
CAUSES TABLE
| Potential Cause | Probability |
|---|---|
| Faulty oxygen sensor | High |
| Corroded or damaged wiring harness | Medium |
| Rich fuel mixture | Medium |
| Faulty fuel injector | Low |
| ECM malfunction | Low |
DIAGNOSTIC STEPS
To diagnose the P0138 error, a technician should start by using a scan tool to monitor the oxygen sensor voltage readings. The readings should change smoothly depending on engine RPM and load. Next, the technician should inspect the oxygen sensor and wiring circuit for any signs of damage or corrosion. The sensor should be checked for proper installation and connection. The technician should also verify with factory specifications in the workshop manual for the specific engine size and type.
HOW TO FIX
Fixing the P0138 code typically involves replacing the faulty oxygen sensor or repairing the wiring circuit. In some cases, the problem may be related to a rich fuel mixture, which can be caused by a faulty fuel injector or a clogged fuel filter. In these cases, the faulty component should be replaced or cleaned. When fixing the P0138 code, it is essential to follow proper troubleshooting procedures to ensure that the root cause of the problem is identified and corrected.
IS IT SAFE TO DRIVE WITH THIS CODE
Driving with the P0138 code active can lead to decreased engine performance, poor fuel economy, and increased emissions. In some cases, it can also cause the engine to stall or hesitate, which can be a safety risk. Therefore, it is recommended to address the issue as soon as possible to avoid any potential risks or damage to the vehicle.
ESTIMATED REPAIR COST
The estimated repair cost for the P0138 code can range from $200 to $500, depending on the specific cause of the problem and the labor rates of the repair shop. In some cases, the cost may be higher if additional repairs are needed, such as replacing a faulty fuel injector or repairing the wiring circuit.
PREVENTIVE MAINTENANCE TIPS
To prevent the P0138 code from occurring, it is essential to follow proper maintenance procedures, such as regularly checking and replacing the oxygen sensor, inspecting the wiring circuit for damage or corrosion, and ensuring that the fuel system is functioning properly. Additionally, using high-quality fuel and avoiding aggressive driving habits can help to reduce the risk of engine problems.
When diagnosing the P0138 code, it is essential to use a scan tool to monitor the oxygen sensor voltage readings and to inspect the sensor and wiring circuit for any signs of damage or corrosion. In my experience, the most common cause of the P0138 code is a faulty oxygen sensor, which can be caused by a variety of factors, including contamination, wear and tear, or manufacturing defects. By following proper troubleshooting procedures and using the correct diagnostic tools, technicians can quickly and accurately diagnose and repair the P0138 code, ensuring that the vehicle is running safely and efficiently.
12. FAQ
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What does code P0138 mean?
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Is it safe to drive with code P0138?
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Will the code clear itself?
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Does the sensor need to be replaced?
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How much does it cost to fix?
RELATED TROUBLE CODES
- Error P0135 on Geely — faulty oxygen sensor heater circuit
- Error P0141 on Geely — oxygen sensor circuit malfunction
- Error P0158 on Geely — faulty oxygen sensor
- Error P0161 on Geely — oxygen sensor circuit malfunction