Scr Aftertreatment Operational Checkout Procedure - Navistar N9 Diagnostic Manual

42 1 DIAGNOSTIC TROUBLESHOOTING PROCEDURES

10.0 - SCR Aftertreatment Operational Checkout Procedure

Overview
The following steps direct technicians to systematically troubleshoot Selective Catalyst Reduction (SCR) exhaust
aftertreatment system problems and avoid unnecessary repairs.
CAUTION: The following service information ONLY applies to N9 and N10 engines with SCR aftertreatment
systems. Using these diagnostics for any other engine or aftertreatment system will result in misdiagnosis and
unnecessary repairs.
Test Procedure
Step 1 Perform preliminary operational checkout procedure.
Did you perform 1.0 Preliminary Vehicle Operational Checkout Procedure?
Step 2 Determine if parked regeneration will not activate.
Press Parked Regen Switch.
Does exhaust aftertreatment regeneration start?
Step 3 Determine if excessive black smoke comes out of exhaust.
Does excessive black smoke come out of exhaust?
Step 4 Determine if excessive white smoke comes out of exhaust.
Does excessive white smoke come out of exhaust?
Decision
Yes: Go to Step 2 (page
42).
No: Go to 1.0 Preliminary
Vehicle Operational
Checkout Procedure
(page 23).
Decision
Yes: Press brake pedal
to abort Parked Regen.
Go to Step 3 (page 42).
No: Go to 10.1 Parked
Regen Will Not Activate
(page 131).
Decision
Yes: Go to 10.2 Black
Smoke (page 133).
No: Go to Step 4 (page
42)
Decision
Yes: Go to 10.3 White
Smoke (page 138).
No: Review operator
complaint.