DDEC III/IV Single ECM Troubleshooting – Section 43.1 Description of Flash Code 43

Section 43.1
Description of Flash Code 43

Flash Code 43 indicates that the ECM has detected that the engine coolant level has dropped below the recommended safe operating range.‪

There is a significant difference between the coolant level sensors used in Detroit Diesel Electronic Controls (DDEC) II and DDEC III/IV applications. ‪

• Externally, the sensors physically look the same, see Figure "Coolant Level Sensor" .
• The sensor used for the DDEC II system has a black colored connector.
• The sensor used for the DDEC III/IV system has an off-white colored connector.

A coolant level module must be used with all coolant level sensors for DDEC II applications. All DDEC III/IV applications, except Volvo, do not require a coolant level module.‪

This code indicates that the coolant level is below the Coolant Level Sensor (CLS) probe or below the Add Coolant Level Sensor (ACLS) if there are two coolant level sensors. Add coolant and return to service. If the code persists with a full coolant level, contact Detroit Diesel Customer Service Center at 313-592-5800.‪