how to repair code 15

Hello, the "low temperature" code would seem to illustrate that either the temperature sensor has failed, the wiring circuit for that sensor, or the engine is indeed running 'cold'. If the sensor reads cold, it affects fuel and air mixture and engine timing. As always - repair what you know to be failing before trying to solve other symptoms. Once you resolve the low temperature code, then see what other symptoms remain.

The coolant temperature *SENSOR* has more than likely failed - - easily tested if you have OBD1 scan tool with live data .. With sensor wire connector disconnected - readings should be well below 0°F ... With connector jumpered - readings should be well over 300°F .. These readings are approximate. While engine is COLD - sensor reading should be *SAME* as ambient temperature ! Sensor failures are common .. Repair DTC 15 before proceeding with any other diagnosis!!