396 7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
ECT Pin-Point Diagnostics
Connector Voltage Checks to Ground (Disconnect harness from sensor. Inspect for bent pins or corrosion.
Connect breakout harness to engine harness only. Turn the ignition switch to ON.)
Test Point
Spec Comment
2tognd 4.6Vto5.0V
Pull up voltage, if no voltage or low, circuit is open, has high
resistance, or short to ground
1 to gnd 0 V to 0.25 V Voltage > 0.25 V, wire shorted to V
REF
or B+.
Connector Resistance Checks to ECM Chassis Ground (Turn the ignition switch to OFF. Disconnect
harness from sensor. Connect breakout harness to engine harness only. D isconnect chassis connector
9260
1
.)
1toPinA(9260) <5Ω If > 5 Ω, check for open ground circuit.
2toPinA(9260) >1kΩ If < 1 kΩ, check for shorted signal to ground within w iri
ng harness.
WARNING: To avoid serious personal injury, poss
ible death, or damage to the engine or vehicle,
always disconnect main negative battery cable fi
rst. 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 batter
y cable. Disconnect harness from sensor. Connect breakout
harness to engine harness only. Use disco
nnected negative battery cable for ground test point.)
1 to gnd cable
>500Ω If < 500 Ω, check for short to ground.
2 to gnd cable
>1kΩ If < 1 kΩ, check for signal short to ground.
Harness Resistance Checks (Connect br
eakout box to engine harness only. Disconnect harness from
sensor. Connect breakout harness to e
ngine harness only.)
X1–6 to 1
<5Ω If > 5 Ω, check for open ground wire
X1–8 to 2
<5Ω If > 5 Ω, check for open signal wire
1
Connector 9260 is a 2-wi r e connector usually lo c ated in the battery box. Pin A is the chassis ground connection for the
ECM and IDM. See truck Chassis Electrical Circuit Diagram Manual 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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