Navistar International DT 466 Diagnostic/Troubleshooting Manual page 536

532 7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
Figure 502 VGT circuit diagram
NOTE: If an Actuator Control Voltage Check was not to specification, continue with this check.
Turn the ignition switch to OFF when disconnecting engine wiring harness connectors from components.
See truck Chassis Electrical Circuit Diagram Manual for circuit numbers, connector and fuse locations.
12-pin Actuator Power Voltage Check (Actuator Control Voltage Check has been completed and
Turbocharger is not connected. Connect 12-pin Breakout Harness to engine and chassis wiring harness.
Turn the ignition switch to ON.)
Test State/Point
10 to 4
10 to chassis gnd
4 to chassis gnd
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Setting/Spec Comment
B+ ± 0.5 V If equal to B+, concern is within engine wiring harness. Do Harness
Resistance Check – VGT Actuator to 12-Pin Connector (page 537).
If < B+, continue with next test point, 10 to chassis ground.
B+ ± 0.5 V If equal to B+, but 10 to 4 did not, the concern is between 12-pin
connector and chassis ground. Check for high resistance or open in
ground circuit. See truck Chassis Electrical Circuit Diagram Manual.
If < B+, disconnect engine wiring harness from 12-pin Breakout
Harness and retest.
• If equal to B+, diagnose engine wiring harness to turbo. Do
Harness Resistance Check – VGT Actuator to 12-Pin Connector
(page 537).
• If < B+, the concern is between 12-Pin Connector and ECM
Main Power Relay. See truck Chassis Electrical Circuit Diagram
Manual.
0 V to 0.25 V If > 0.25 V disconnect engine wiring harness from 12 - Pin Breakout
Harness and retest.
• If < 0.25 V, diagnose engine wiring harness, do Harness
Resistance Check – VGT Actuator to 12-Pin Connector (page
537).
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
EGES-270-1