532 7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
Figure 502 VGT circuit diagram
NOTE: I f an Actuator Co ntrol Voltage Check wa
s not to specification, continue w ith this check.
Turn the ignition switch to OFF when disconne
cting engine wiring harness connectors from components.
See truck Ch assis Electrical Circuit D iag ra
m M anual 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 Setting/Spec Comment
10 to 4 B+ ± 0.5 V
If equal to B+, concern is within engi
ne wiring harness. Do Harness
Resistance Check – VGT Actuator to 1
2-Pin Connector (page 537).
If < B+, cont inue with nex t test po
int, 10 to chassis ground.
10 to chassis gnd 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 C ircuit 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. D o
Harness Resistance Check – VGT A ctuator to 12-Pin Connector
(page 537).
• If < B+, the concern is between 12-Pin Connector and ECM
Main Power Relay. See truck Chassis E lectrical Circuit Diagram
Manual.
4tochassisgnd 0Vto0.25V
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 A ctuator to 12-Pin Connector (page
537).
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.
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