71.1 DESCRIPTION OF FLASH CODE 71
Flash Code 71 indicates that the time it takes from when the DDEC ECM, see Figure 71-1,
requests an injector be turned on 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
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
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.).
All information subject to change without notice.
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION