Iat Pin-Point Diagnostics - Navistar International DT 466 Diagnostic/Troubleshooting Manual

7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS

IAT Pin-Point Diagnostics

Figure 460 IAT circuit diagram
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
2 to gnd 0 V to 0.25 V
1 to gnd 4.6 V to 5.0 V
Connector Resistance Checks to ECM Chassis Ground (Turn the ignition switch to OFF. Disconnect
harness from sensor. Connect breakout harness to engine harness only. Disconnect chassis connector
1
9260 .)
2 to Pin A (9260) < 5 Ω
1 to Pin A (9260) > 1 kΩ
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
1
connector 9260 . Disconnect negative battery cable. Disconnect harness from sensor. Connect breakout
harness to engine harness only. Use disconnected negative battery cable for ground test point.)
2 to gnd cable > 500 Ω
1 to gnd cable > 1 kΩ
Harness Resistance Checks (Connect breakout box to engine harness [X1 only] and chassis harness
[X4 only].)
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Comment
Signal ground (No voltage expected). If > 0.25 V, signal wire is
shorted to V or B+.
REF
Pull up voltage, if no voltage, circuit has open, high resistance,
or short to ground.
If > 5 Ω, check for open circuit.
If < 1 kΩ, check for short to ground within wiring harness.
If < 500 Ω , check for short to ground.
If < 1 kΩ, check for short to ground.
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
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