Code Definition

P1191 — Key line voltage

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

About P1191

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

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

This fault code is set when the engine control module (ECM) detects an issue with the key line voltage, which relates to the vehicle ignition switch and immobiliser system. The key line is the signal that confirms the ignition is switched on and, on many PSA applications, forms part of the communication between the BSI body controller, the immobiliser, and the ECM. A fault on this line can prevent the ECM from being woken or authorised correctly, resulting in hard starting, a no start, or an immobiliser condition. The driver may experience intermittent starting problems or warning messages on ...

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