Navistar INTERNATIONAL DT 466 - Page 302

298 7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
DTC 354 – VGT control under duty cycle
DTC 354 is set when the ECM overcompensates by decreasing duty cycle to the VGT to achieve the
desired boost/back pressure.
Possible Cause Comment
BAP sensor bias high
Check sensor signal voltage. See “BAP Sensor” (page 314).
MAP sensor bias high
Check sensor signa l voltag e. See “M AP Se ns or” (pag e 50 0 ).
EBP sensor bias high
Check sensor signal voltage. See “EBP Sensor” (page 359).
Open Exhaust (no muffler)
Inspect exhaust s ystem .
ICP sensor bias low Check sensor signal voltage. See “ICP Sensor” (page 457).
ICP system integrity Do “Performance Diagnostics” (page 205).
Injector operation / part number Check previous repairs. Do “Performance Diagnostics
” (page
205).
Exhaust restriction (muffler or catalytic
converter)
Inspect exhaust. Do“Performance Diagnostics” (page 205).
VGT control circuit short to B+. Do VGT Pin-Point Diagnostics. See “VGT Actuator” (page 524).
VGT actuator or vanes stuck Do “Performance Diagnostics” (page 205).
DTC 355 – VGT overspeed
DTC 355 is set w hen the ECM detects turbo over speed several times in a specific period of time (dependent
on ECM calibration). Turbo speed is estimated by engine speed, boost pressure, and barometric pressure.
Possible Cause Comment
High intake restriction
Do “Performance Diagnostics” (page 205).
Intake / CAC s ystem leak (pipes, loose
clamps, hoses)
Do “Performance Diagnostics” (page 205).
Restricted CAC system Do “Performance Diagnostics” (
page 205).
VGT actuator or vanes sticking Do “Performance D iagnostics” (page 205).
Open exhaust (no muffler)
Inspect exhaust system
BAP sensor bias
Check senso r sig nal v o ltag
e. See “BAP Sensor” (page 314).
MAP sensor bias high
Check sensor signa l voltag e. See “M AP Se ns or” (pag e 50 0 ).
EBP sensor bias low
Check sensor signal voltage. See “EBP Sensor” (page 359).
EGES-270-1
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.