7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS 409
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.
Circuit Checks for EFP Sensor (Use EST, DMM, breakout harness, and 500 O
hm Resistor Harness.)
Test Condition Spec Checks
Sensor disconnected using EST
0V
If voltage > 0.039 V, check signal circuit f or short to V
REF
or B+.
Voltage from Pin 2 (Blue) to
ground using DMM
5V±0.5V
If voltage > 5.5 V, check V
REF
for short to B +. If voltage is
<4.5V,checkV
REF
for open or short to ground.
500 Ohm Resistor Harness
connected between Pin 3
(Green) and Pin 2 (Blue) of
breakout harness using EST
5V
If voltage < 4.9 V, check signal circuit for open or short
to ground.
— D isconnect connector 9260
1
. Measure resistance
from Pin 3 to Pin A of connector 9260 (spec > 1 kΩ)
to check for short to ground within wiring harness.
— D isconnect negative battery cable. M easure
resistance from Pin 3 to ground cable to check for
short to ground.
— U se a breakout box from Pin 3 to Pin X2–16 (spec <
5 Ω) to check for open in the harness.
Resistance from Pin 1 (Black) of
breakout harness to ECM chassis
ground (Pin A of connector 9260)
using DMM
<5Ω If resistance is > 5 Ω, check for open or h igh resistance
between ECM and sensor connector. Use a breakout
box and measure resistance from between Pin 1 and Pin
X1–6 (spec < 5 Ω).
Connect engine harness to sensor. U
se the EST to clear DTCs. If an active code remains after
checking test conditions, replac
e the EFP sensor.
1
Connector 9260 is a 2-w ire connecto
r usual ly located in the battery bo x . Pin A is the chassis gro und 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.
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