P0138 on Suzuki Wagon R: O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)

Short answer: P0138 means “O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)”. The car’s computer has found a fault in the Emissions system and turns on the Check engine light (MIL). First check: read the code and live data with an OBD-II scanner.

Standard OBD-II code Same meaning on all cars (SAE J2012). Not checked against this car’s factory manual.

Code

P0138

System

Emissions

Dashboard light

Check engine light (MIL)

Also sold as

Maruti Suzuki Wagon R, Suzuki Karimun Wagon R (Indonesia)

Applies to

Generic OBD-II meaning. Not every code is used by this car.

Confidence

medium (generic OBD-II definition, not checked against the factory manual for this car)

Source

obd-codes.com

Symptoms and when it is set

1. Check engine light on
2. Fuel pressure can over rich the system

Likely causes

1. Faulty O2 sensor
2. Short to battery voltage in O2 sensor signal circuit
3. High fuel pressure (not as likely)

What to check, in order

1. Read the code and live data with an OBD-II scanner
2. Look for exhaust or vacuum leaks and check the wiring of the sensor or valve
3. Test the part before replacing it
4. Fix the cause, clear the code and test-drive

Related on this car

• All fault codes for this car
• Warning lights
• Where the parts are (parts map)
• Common problems

Same code on other cars

• P0138 · Toyota Passo (1st gen)
• P0138 · Toyota Corolla (11th gen, E170)
• P0138 · Toyota Corolla (10th gen, E140)
• P0138 · Honda City (5th gen, GM2)
• P0138 · Honda Civic (10th gen, FC)
• P0138 on all cars compared

← P0137 P0141 →

Clearing the code does not fix the fault. If it comes back, the problem is still there. For brakes, airbags and steering, see a trained mechanic.