DIAGNOSTIC MANUAL
3.4. SYMPTOM 3 (MEDIUM DUTY): SPN 3719 OR SPN 3936 ACTIVE ONLY OR
FREQUENT REGENS (MORE THAN ONE PARKED REGEN PER DAY)
NOTE – Before beginning the following step-based diagnostics, perform all vehicle operational checks
page 5.
NOTE – The number of regens performed in one day may vary depending on application. The following
criteria should be used to determine if a regen is considered frequent:
•
Line-haul: More than 1 parked regen per day is frequent regeneration.
•
Severe service: More than 2 parked regens per day is frequent regeneration.
Step
Action
Decision
1
Using Electronic Service Tool (EST) with ServiceMaxx™ software,
check Diagnostic Trouble Code (DTC) list to determine which of
the following fault codes is active: SPN 3719/3936 FMI 0, 15, or
16.
Which fault code is active?
SPN 3719 or SPN 3936 FMI
0: Go to step 2
SPN 3719 or SPN 3936 FMI
16: Go to step 4
SPN 3719 or SPN 3936 FMI
15: Go to step 5
Step
Action
Decision
2
Do three Onboard Filter Cleanliness Tests (OBFCT) to decrease
soot load of Diesel Particulate Filter (DPF). Using EST, go to Tests
> KOER Aftertreatment Tests > Onboard Filter Cleanliness Test.
After OBFCTs are complete, check DTC list to determine if SPN
3719 FMI 0 dropped one FMI level to SPN 3719 FMI 16.
Did SPN 3719 FMI 0 drop one FMI level to SPN 3719 FMI 16?
Yes: Go to step 3
No: Go to step 4
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