Code Definition

P1191 — Oxygen Sensor Heater Open Circuit

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Jaguar

About P1191

P1191 is a manufacturer-specific powertrain diagnostic trouble code recorded for Jaguar vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1191 is stored, the module has detected an open (broken or disconnected) electrical path in the monitored circuit; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1191 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

DTC P1191 on these Jaguar applications is set when the engine control module (ECM) detects an open circuit in an oxygen sensor heater element or its control circuit. The integral heater brings the sensor to operating temperature quickly, typically several hundred degrees Celsius, so the ECM can enter closed loop control and read the air fuel mixture accurately. When the heater circuit is open the sensor warms too slowly or not at all, which delays closed loop operation and disturbs fuel trim and emissions. The malfunction indicator lamp will usually illuminate, and a cold or lazy sensor may al...

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