What does it mean?
P1113 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: O2 Control (Bank 1 Sensor 1) Internal Resistance Too High .
Symptoms
- Check engine light on with the sensor slow to become active after a cold start
- Engine staying in open loop longer than normal, giving a rich mixture and higher consumption
- Rough or uneven idle during warm-up
- Hesitation and weak throttle response until the exhaust heats the sensor
- Readiness monitors failing to complete, blocking an emissions test
- Fuel smell from the exhaust in the first minutes of running
Likely causes
- Open or failing heater element inside the sensor, so the ceramic never reaches operating temperature
- Blown fuse or an open supply wire feeding the sensor heater
- High-resistance or corroded terminals in the sensor connector
- Aged sensor whose element resistance has risen with mileage and heat cycling
- Contamination of the element by oil, coolant or silicone sealant fumes
- Poor ground or a broken heater control wire back to the module
- Failed heater driver inside the module, checked last
How to fix it
- Watch how long the sensor takes to start switching after a cold start; an unusually long delay supports the code
- Check the sensor heater fuse and confirm battery voltage at the heater supply pin with the ignition on
- Measure the heater element resistance across the sensor terminals and compare it with the specification; an open reading condemns the sensor
- Inspect the connector for green corrosion, melted plastic and heat damage from the exhaust
- Voltage-drop test the heater ground or control wire back to the module
- Check for oil or coolant consumption that could be poisoning the element before fitting a new sensor
- Replace the sensor if the heater or element fails the tests, then confirm normal switching activity after warm-up