DDEC III/IV Single ECM Troubleshooting – Section 71.1 Description of Flash Code 71

Section 71.1
Description of Flash Code 71

Flash Code 71 indicates that the time it takes from when the DDEC ECM requests an injector be turned on, to when the injector solenoid valve actually closes, is shorter than the lower limit of the expected range.‪

This diagnostic condition is typically:‪

• Aerated fuel system
• High system battery (+) supply voltage
• Mechanical injector failure
• Failed solenoid

Note: The injector diagnostic SID (Subsystem Identifier) indicates which cylinder number has an injector with a short response time. The injector number describes the cylinder and bank that has the injector with a short response time. The DDR will display the injector text description.

Injector response times generally increase with low battery supply voltage and decrease with high battery supply voltage. Although injector response times vary from injector to injector at a given r/min, each individual injector response time should remain relatively consistent from one firing to the next. Wide variations in response time (typically ± 0.2 ms) for one injector at a steady engine r/min may indicate an electrical problem (faulty alternator or regulator, poor or broken ground cables, etc.). See Figure "Injectors" for injector diagram.‪