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 code refers to a problem with the oxygen sensor circuit in your Geely’s engine. Specifically, it indicates that the voltage reading from the Bank 1 Sensor 2 oxygen sensor is higher than expected. This sensor is responsible for monitoring the amount of oxygen in the exhaust gases and providing this information to the engine control module (ECM). The ECM uses this data to adjust the air-fuel mixture and ensure that the engine is running efficiently.
Common Geely models affected
- Geely Emgrand EC7
- Geely Emgrand EC8
- Geely GC2
- Geely GC5
- Geely CK
Symptoms
- Check Engine Light illumination
- Poor engine performance
- Decreased fuel efficiency
- Rough idling
- Difficulty starting the engine
- Increased emissions
- Failed emissions test
Causes Table
| Potential Cause | Probability (High/Medium/Low) |
|---|---|
| Faulty oxygen sensor | High |
| Wiring issues or damaged connectors | Medium |
| Failed or faulty engine control module (ECM) | Low |
| Rich or lean fuel mixture | Medium |
| Exhaust system leaks or blockages | Medium |
| Intake system leaks or blockages | Low |
Diagnostic Steps
To diagnose the P0138 code, start by using a scan tool to monitor the oxygen sensor readings. The readings should change smoothly depending on engine RPM and load. If the readings are stuck or not changing, it may indicate a faulty sensor. Next, inspect the wiring and connectors for any signs of damage or corrosion. Check the exhaust and intake systems for any leaks or blockages. Finally, use a multimeter to test the voltage at the oxygen sensor circuit to ensure it is within the specified range.
How to Fix
The primary repair method for the P0138 code is to replace the faulty oxygen sensor. This involves locating the sensor, disconnecting the electrical connector, and removing the sensor from the exhaust system. A new sensor can then be installed and the electrical connector reconnected. In some cases, it may also be necessary to repair or replace the wiring or connectors, or to address any underlying issues with the engine’s fuel system.
Is it safe to drive with this code
Driving with the P0138 code can cause decreased fuel efficiency, poor engine performance, and increased emissions. While it is not typically considered an emergency situation, it is recommended to address the issue as soon as possible to avoid any potential damage to the engine or catalytic converter. Additionally, if the Check Engine Light is illuminated, it may be a requirement to pass an emissions test.
Estimated Repair Cost
The estimated repair cost for the P0138 code can range from $200 to $500, depending on the cost of the oxygen sensor and any additional repairs that may be necessary. In some cases, the cost may be higher if the problem is more complex or if other components need to be replaced.
Preventive Maintenance Tips
To prevent the P0138 code from occurring, it is recommended to regularly inspect the oxygen sensor and wiring for any signs of damage or corrosion. Additionally, keeping the engine’s fuel system clean and well-maintained can help to prevent any underlying issues that may contribute to the code. It is also a good idea to use a high-quality fuel filter and to avoid using low-quality or contaminated fuel.
Related Trouble Codes
- Error P0133 on Geely — faulty oxygen sensor circuit
- Error P0135 on Geely — faulty oxygen sensor heater circuit
- Error P0141 on Geely — faulty oxygen sensor circuit
- Error P0158 on Geely — faulty oxygen sensor circuit