7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS 427
EOP Circuit Operation
Figure 445 EOP circuit diagram
The EOP sensor is supplied with a 5 V reference
voltage at Pin 2 from ECM Pin X1–14. The EOP
sensor is grounded at Pin 1 from ECM Pin X1–6. The
EOP sensor returns a variable voltage signal from Pin
3toECMPinX2–7.
Fault Detection / Management
When the EOP signal voltage is detected out of range
high or low, the ECM will cause the engine to ignore
the EOP signal and disable the EWPS.
EOP Diagnostic Trouble Codes (DTCs)
DTCs are read using the EST or by counting the
flashes from the amber and red ENGINE lamp.
DTC 211
EOP signal out-of-range low
• DTC 211 is set by the ECM when the EOP signal
is less than 0.039 V for more than 0.35 second.
• DTC 211 can be set due to an open or short to
ground o n the signal circuit, a failed ICP sensor
or an open V
REF
circuit or V
REF
short to ground.
• When DTC 211 is active the amber ENGINE lamp
is illuminate d.
DTC 212
EOP signal out-of-range high
• DTC 212 is set by the ECM when the EOP signal
is greater than 4.9 V for more than 0.35 sec o nd.
• DTC212canbesetduetosignalcircuitshortto
V
REF
or B+, or a failed EOP sensor.
• When DTC 212 is active the amber ENGINE lamp
is illuminated.
DTC 225
EOP sensor signal in-range fault
• DTC 225 is set by the ECM when the EOP
signal voltage is greater than 207 kPa (30 psi)
for 8 seconds or more with the ign ition key -on
engine-off.
• DTC 225 can be set due to an open signal ground,
V
REF
shorted to voltage source above 5.5 V, biased
circuit, failed EOP sensor.
• When DTC 225 is active the amber ENGINE lamp
is illuminated.
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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