P0115

Engine Coolant Temperature (ECT) sensor circuit malfunction

Detection Condition

• The signal from the engine coolant temperature sensor to the ECU has fallen below 0.2V or risen above 4.9V

Diagnostic Support Notes

• This is a continuous monitor (CCM)
• The check engine indicator illuminates if ECU detects the above malfunction condition during the first drive cycle
• PENDING CODE not available
• FREEZE FRAME DATA is available
• DTC is stored in ECU memory

Possible Causes

• Engine coolant temperature sensor malfunction
• Short to power circuit between ECU and instrument cluster
• Short to ground circuit between ECU and instrument cluster
• Short to ground circuit between ECT sensor terminal A and ECU
• ECT signal and ground circuits are shorted
• Open circuit between ECT sensor terminal A and ECU
• Short to power circuit between ECT sensor terminal A and ECU
• Open circuit between ECT sensor terminal B and ECU
• Poor connection of ECT sensor or ECU connectors
• ECU malfunction

[P0115 - From 2002 Mazda Millenia factory service manual]