Code Definition

P1139 — Water in Fuel Indicator circuit

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

About P1139

P1139 is a manufacturer-specific powertrain diagnostic trouble code recorded for Ford vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1139 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

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.

P1139 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

The Powertrain Control Module (PCM) monitors the Water in Fuel (WIF) sensor circuit, which detects water contamination in the diesel fuel filter housing. The WIF sensor changes its resistance according to the dielectric properties of the fuel, and when water is present the resistance shifts, prompting the PCM to activate the warning indicator. DTC P1139 is set when the PCM detects an electrical fault in the WIF circuit, such as an open circuit, a short to ground, or a short to voltage, rather than an actual water contamination event. The driver may see a water in fuel warning lamp, and on some...

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