P1138 – Ford DTC

Ford DTC P1138 – Lack of Downstream Heated Oxygen Sensor Switch – Sensor Indicates Rich – Bank No. 1

DTC P1138 meaning on Ford

1. DTC: P1138
2. Definition: Lack of Downstream Heated Oxygen Sensor Switch – Sensor Indicates Rich – Bank No. 1
3. Meaning: The downstream oxygen sensor in Bank 1 is indicating a rich air-fuel mixture condition, which means there is an excess of fuel in the exhaust gases.

Ford DTC P1138 symptoms

• Check Engine Light (MIL) illuminated
• Decreased fuel efficiency
• Rough idling or engine misfires
• Increased emissions

Ford DTC P1138 causes

• Faulty downstream heated oxygen sensor
• Rich air-fuel mixture due to issues with fuel injectors
• Vacuum leaks in the intake system
• Issues with the engine’s air intake system

Ford DTC P1138 seriousness

1. Seriousness: While the vehicle may still be operable with this issue, it can lead to decreased fuel efficiency and increased emissions, potentially causing long-term damage to the engine and catalytic converter.

How to diagnose DTC P1138 on Ford

1. Use an OBD-II scanner to retrieve the DTC P1138 code
2. Inspect the downstream heated oxygen sensor in Bank 1 for any signs of damage or contamination
3. Check for vacuum leaks in the intake system
4. Inspect the fuel injectors for proper operation

How to fix DTC P1138 on Ford

1. Replace the downstream heated oxygen sensor in Bank 1 if faulty
2. Clean or replace fuel injectors if necessary
3. Repair any vacuum leaks in the intake system
4. Ensure the engine’s air intake system is functioning correctly

How to erase DTC P1138 on Ford

1. After fixing the underlying issue causing DTC P1138, use an OBD-II scanner to clear the code
2. Drive the vehicle to allow the system to retest and ensure the code does not return