P2237, P2238 Exhaust leak, Oxygen sensor failure, Powertrain Control Module (PCM) failure

Land Rover OBD-II Trouble Codes -------------------------------------------------The diagnostic trouble codes (DTCs) P2237 and P2238 both relate to issues with the Oxygen (O2) sensor in the exhaust system. Additionally, P2237 mentions a potential exhaust leak, and both codes mention the possibility of a Powertrain Control Module (PCM) failure. Here's a breakdown of each code:

1. **P2237 - Oxygen Sensor Positive Current Control Circuit/Open (Bank 1 Sensor 1):**

   - This code indicates a positive current control circuit/open issue in the Oxygen Sensor for Bank 1 Sensor 1. This sensor is typically located upstream of the catalytic converter.

2. **P2238 - Oxygen Sensor Positive Current Control Circuit Low (Bank 1 Sensor 1):**

   - Similar to P2237, but P2238 specifies a low voltage condition in the Oxygen Sensor for Bank 1 Sensor 1.

### Possible Causes:

1. **Faulty Oxygen (O2) Sensor:** Issues with the O2 sensor itself, such as sensor degradation, failure, or a poor connection.

2. **Wiring Issues:** Problems with the wiring or connectors associated with the O2 sensor circuit.

3. **Exhaust Leak:** Leaks in the exhaust system may impact O2 sensor readings.

4. **Powertrain Control Module (PCM) Issues:** A potential failure or malfunction in the PCM, which controls and monitors various aspects of the engine and emissions system.

### Diagnostic Steps:

1. **Inspect Oxygen (O2) Sensor:** Check the O2 sensor for signs of damage or wear. If it appears faulty, consider replacement.

2. **Check Wiring and Connectors:** Inspect the wiring and connectors associated with the O2 sensor circuit. Look for any signs of damage, corrosion, or loose connections.

3. **Test Oxygen (O2) Sensor Operation:** Use a multimeter or diagnostic tool to test the operation of the O2 sensor. Check for proper resistance or voltage readings.

4. **Inspect for Exhaust Leaks:** Check the exhaust system for leaks, as they can impact O2 sensor readings.

5. **Perform Continuity Tests:** Check for continuity in the wiring from the O2 sensor to the PCM.

6. **Verify PCM Operation:** Test the PCM for proper operation. Replace if necessary.

7. **Clear Codes:** After addressing any identified issues, clear the trouble codes and monitor the system for recurrence.

8. **Consider Professional Assistance:** If you are unsure about diagnosing or addressing these issues yourself, or if the faults persist, it's advisable to consult with a qualified mechanic or technician.

Addressing the root cause of the O2 sensor circuit faults is crucial for proper emission control and compliance with environmental standards. If in doubt or if the faults persist, seeking professional assistance is recommended for a thorough diagnosis and effective repair.