Code Definition

P1290 — Engine coolant temperature sensor input too high

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

About P1290

P1290 is a manufacturer-specific powertrain diagnostic trouble code recorded for Audi vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1290 is stored, the module has detected a signal or supply voltage higher than the expected operating range; 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.

P1290 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 engine coolant temperature sensor is a negative temperature coefficient thermistor mounted in the coolant flange, supplied with a 5V reference through a pull up resistor inside the Engine Control Module. The module reads the voltage that results on the signal wire, so a cold engine returns a high signal voltage and a hot engine a low one. DTC P1290 is stored when that input rises above the upper plausibility limit, which on this circuit means a signal voltage higher than the sensor could produce at any realistic temperature and is therefore read as an implausibly cold engine. The usual cau...

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