7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS 307
WARNING: To avoid serious personal injury, possible death, or damage to the engine or vehicle,
always disconnect main negative battery cable first. Always connect the main negative battery cable
last.
Connector Resistance Checks to Chassis Ground (Turn the ignition switch to OFF. Disconnect chassis
connector 9260
1
. Disconnect negative battery cable. Disconnect harness from sensor. Use disconnected
negative battery cable for ground test point.)
A to gnd cable
>1kΩ If < 1 kΩ, check for short to ground.
B to gnd cable
> 500 Ω If < 500 Ω, check for open signal ground.
C to gnd cable > 500 Ω If < 500 Ω, check for short to g round.
D to gnd cable
>1kΩ If < 1 kΩ, check for short to ground.
F to gnd cable
>1kΩ If < 1 kΩ with fuse removed, check for short to ground.
Harness Resistance Checks (Connect breakout box [X4 only] to chassis harness only. Connect breakout
harness to chassis harness only.)
X4–18 to A
<5Ω If > 5 Ω, check for APS signal wire open.
X4–24 to B
<5Ω If > 5 Ω, check for open signal ground.
X4–4 to C < 5 Ω If > 5 Ω, check for open V
REF
wire.
X4–12 to D
<5Ω If > 5 Ω, check for open IVS signal wire.
Fuse to F
<5Ω If > 5 Ω, check for open IVS power wire.
NOTE: See truck Chassis Electrical Circuit Diagram Manual for fuse location.
1
Connector 9260 is a 2-wire connector us ually located in the battery box. Pin A is the chassis ground connection for the
ECM and IDM. See truck Chassis Electrical Circuit Diagram Manual for comp lete chassis s ide ECM and IDM g r ou nd
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.