What does it mean?
P1196 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: O2 Sensor Heater Circuit (Bank 1-Sensor 1) Electrical Malfunction .
Symptoms
- Check engine light on a few minutes after a cold start
- Delayed closed loop entry with rich running during warm-up
- Slight idle roughness while the engine is cold
- Extra fuel used on short trips
- Readiness monitors incomplete, blocking an emissions test
- Symptoms disappear once the engine is fully warmed up
Likely causes
- Heater element inside the sensor open or shorted after long service
- Corroded or water-filled connector, especially where the sensor sits low and is exposed to spray
- Heater ground path corroded or loose at its mounting point
- Supply wire chafed against the exhaust or a heat shield
- Blown fuse shared with other heater circuits
- Heater driver in the control module failed
- Aftermarket sensor with a heater specification that does not match the module
How to fix it
- Inspect the heater fuse and any relay in the circuit before anything else
- Measure heater element resistance across the sensor heater pins and compare with specification
- With the ignition on, confirm supply voltage at the harness connector
- Voltage-drop test the heater ground path to expose a corroded or loose connection
- Open the connector and check for water, corrosion and burnt terminals; dry and reseal it
- Repair or replace the damaged harness section, keeping it clear of the exhaust
- Fit a correct-specification oxygen sensor if the element is faulty, then clear codes and verify the heater monitor completes