Navistar MaxxForce DT Diagnostic Manual page 89

Step
2C Verify aftertreatment system is free of restrictions. Using EST,
use the playback feature and graph the following signal values
from Lug Down Test:
Signal Values:
• Engine Speed
• Turbocharger 1 Turbine Outlet Pressure (TC1TOP)
Compare snapshot to Graph 4 and associated Graph Analysis
page 126.
Is TC1TOP signal operating as per Graph 4 Graph Analysis?
Step
2D Check for an Intake Manifold Pressure (IMP) issue. Use the
playback feature in ServiceMaxx™, and graph the following
signal values from Lug Down Test:
Signal Values:
• Engine Speed
• Intake Manifold Pressure (IMP)
• Accelerator Pedal Position 1 (APP1)
• Vehicle Speed
Compare snapshot to Graph 5 and associated Graph Analysis
page 127.
Is IMP operating as per Graph 5 Graph Analysis?
Action
Action
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DIAGNOSTIC MANUAL
Decision
Yes: Go to step 2D
No: Repair TC1TOP issue (See
Electronic Control Systems
Diagnostics in Engine Diagnostic
Manual). After repairs are complete,
retest for original problem.
Decision
Yes: Go to step 3
No: Diagnose and repair IMP issue
(See Performance Diagnostics
section in Engine Diagnostic
Manual). After repairs are complete,
retest for original problem.
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