454 7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
4. Ifcodeisactive,dostep6and7tocheckcircuit
for the IAT sensor usin g the fo llowing table .
• Circuit Checks for IAT Sensor
5. If code is inactive, wiggle connectors and wires
at all suspected problem locations. If circuit
continuity is inte rrup ted, the EST will display
DTCs related to the condition.
6. Disconnect chassis harness from temperature
sensor.
NOTE: Inspect connectors for damaged pins,
corrosion, or loose pins. Repair if necessary.
7. Connect Temperature Sensor Breakout Harness
to engine harness only.
Circuit Checks for IAT Sensor (Use EST, breakout harness, 3-Banana Plug Harness, and 500 Ohm
Resistor Harness.)
Test Condition Spec Checks
Sensor disconnected
>4.6V
If voltage < 4.6 V, check signal circuit for short to ground.
3-Banana Plug Harness
connected between Pin 1
(Green) and P in 2 (Black) of
breakout harness
0V
If voltage is > 0.127 V, check ground and signal circuit
for open or high resistance. Use a breakout box and
measure resistance from Pin 2 to Pin X4–24 and from
Pin 1 to X1–7 (spec < 5 Ω).
500 Ohm Resistor Harness
connected between Pin 1
(Green) and P in 2 (Black) of
breakout harness
<1.0V
If voltage > 1.0 V, check signal circuit
for short to V
REF
,B+,
or another sensor’s signal voltage
.
Connect engine harness to sensor. Use the EST to clear DTCs. If an active code remains after
checking test conditions, replace the IAT sensor.
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.
To Next Page
Loading...
Need help?
General