DIAGNOSTIC MANUAL
10.4. GRAPH 4: LUG DOWN TEST (ENGINE SPEED AND TC1TOP)
1. Turbocharger 1 Turbine Outlet
Pressure (TC1TOP) (psi) [Blue]
2. Engine Load (Percent) [Red]
3. Accelerator Pedal Position 1
(APP1) (Percent) [Green]
Figure 29
Graph 4: Lug Down Test (Engine Speed and TC1TOP)
Graph Analysis:
This graph shows an exhaust aftertreatment system operating as designed (unrestricted). This test does not
give pass or fail results. It only allows the user to validate Turbocharger 1 Turbine Outlet Pressure (TC1TOP)
signal value under load. High TC1TOP will cause low Intake Manifold Pressure (IMP). Diagnose high TC1TOP
concerns before diagnosing low IMP concerns.
Actions:
1.
Verify TC1TOP signal value is less than 5 psi (34 kPa) during Lug Down Test.
NOTE – Analyze Lug Down Test signal values only during engine acceleration, and not deceleration or
shifting.
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