496 7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
IPR Pin-Point Diagnostics
The IPR circuit requires the use of v ehicle circuit diagrams. See truck Chassis Electrical Circuit Diagra m
Manual for circuit numbers, connector and fuse locations.
IPR Voltage Checks (Disconnect regulator connector. Connect break
out harness to engine harness only.
Turn the ignition switch to ON.)
Test Point
Spec Comment
Atognd B+
IPR power from V
IGN
– If no voltage, c heck from fuse to IPR co nnector.
See truck Chassis Electrical Circuit Diagram Manual for circuit
numbers, connector and fuse locations.
B to gnd 0 V to 0.25 V
If > 0.25 V, control wire is shorted to V
REF
or B+.
Connector Resistance Checks to ECM Chassis Ground (Turn the ignition switch to OFF. Connect
breakout harness to engine harness only. Disconnect chassis connector 9260
1
.)
1 to Pin A (9260) > 1 kΩ Resistance to chassis ground. If < 1 kΩ, check for short to ground in
circuit (check w ith fuse removed)
2 to Pin A (9260) > 1 kΩ If < 1 kΩ, check for short to ground
Harness Resistance Checks - 12-pin Connector to IPR Connector (Turn the ignition switch to OFF.
Connect 12- pin breakout harness to engine harness only. Connect actuator breakout harness to engine
harness only. Check with fuse removed.)
Pin9toA
<5Ω If > 5 Ω check for open circuit.
Harness Resistance Checks - IPR Circ
uit Including Regulator (Turn the ignition switch to OFF. Connect
Breakout Box X1 to engine harness on
ly. Connect engine harness to IPR. Check with fuse remove.)
X1-12tofuse 5Ω to 20 Ω Resistance through entire IPR circuit including regulator. If not within
specification do Actuator Resistance Check.
Actuator Resistance Checks (Turn the ignition switch to OFF. Disconnect the connector from the IPR,
connect breakout harness to IPR only. Check resistance through the IPR only.)
AtoB
5 Ω to 20 Ω Resistance through IPR coil
only. If not within specification replace
IPR.
IPR Diagnostic Trouble Codes
DTC 241 = Output Circuit Check detected during KOEO Standard Test, indicates high or low resistance in
circuit.
1
Connector 9260 is a 2-wire con nector usually locate d in the battery box. Pin A is the ground connection fo r th e E CM
and IDM. See truck Chassis Electrical Circuit Diagram Manual for complete chassis side ECM and IDM groun d 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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