7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS 343
Harness Resistance Check – 12-Pin Connector to ECM Chassis Ground (Turn the ignit
ionswitchtoOFF.
Connect 12-pin Breakout Harness to chassis wiring harness only. Disconnect ch
assis connector 9260
1
.)
4toPinA(9260) <5Ω If > 5 Ω, check for open in chassis w iring harness ground circuit.
Harness Resistance Check – 12-Pin Connector to Chassis Ground (Turn the ignition switch to OFF.
Disconnect chassis connector 9260
1
. Disconnect negative battery cable. Disconnect 12–pin connector and
use chassis side for test point. Use disconnected negative battery cable for ground test point.)
4 to gnd cable
<500Ω If > 500 Ω, check for short to ground.
Harness Resistance Check – Valve Cover Gasket Connector to 12-Pin Connector (Connect VC
Gasket Breakout Harness to engine wiring harness only. Connect 12-Pin Breakout Harness to engine
wiring harness only.)
Ato4
1
<5Ω If > 5 Ω, check for open in actuator ground.
Harness R esistance Check – Valve Cover Gasket Conn
ector to ECM (Connect VC Gasket Breakout
Harness to engine wiring harness only. Connect bre
akout box X2 to engine wiring harness only.)
CtoX2-18 <5Ω If > 5 Ω, check for open in control wire.
Resistance Check – Valve Cover Gasket, UVC Wiring, and Brake Shut-off Valve/Solenoid (Connect VC
Gasket Breakout Harness to valve cover gasket only.)
AtoC 10Ω ±2Ω •If>12Ω, the concern is the valve cover gas
ket, UVC wiring, or
brake shut-off valve/solenoid. Do Harn
ess Resis tance Check – Va lve
Cover G asket Connector to UVC Conne
ctor (page 346) and Solenoid
Resistance Check – Brake Shut-off V
alve (page 346).
•If<8Ω, a short to ground exists. The
concern is the valve cover
gasket, UVC wiring, or brake shut-
off valve/solenoid.
1
Connector 9260 is a 2-w ire connecto
r usually located in the battery box. Pin A is t he ground connection for the ECM
and IDM. See truck Chassis Electrical C ircuit Diagram M anual for complete chassis side ECM and IDM g round circuit
information.
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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