DDEC III/IV Single ECM Troubleshooting – Section 27.1 Description of Flash Code 27

Section 27.1
Description of Flash Code 27

Flash Code 27 indicates that the engine Air Temperature Sensor (ATS), see Figure "Air Temperature Sensor" , input to the ECM has exceeded 95% (normally > 4.75 volts) of the sensor supply voltage.‪

Note: This code will only be logged during warm engine operation.

This diagnostic condition is typically:‪

• Open sensor signal circuit
• Open sensor return circuit