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

490 7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
low side output supplies a return circuit to each injector
coil.
The injectors are under the valve covers.
injector has a close and open coil.
continuously monitors the amount of time (rising time)
taken by each coil to draw 20 A. The time is compared
to calibrated values and the IDM determines if a
circuit or injector fault exists. Each injector has 6
failure modes and 3 DTCs. A failure can occur on the
open or close coil circuit.
When a short to ground condition is detected on an
injector (low or high side), the IDM discontinues power
to the shorted injector and operates the engine on the
remaining cylinders.
INJ Diagnostic Trouble Codes (DTCs)
DTCs are read using the EST or by counting the
flashes from the amber and red ENGINE lamp. The
last digit in the injector DTC corresponds to the
cylinder where a fault has been detected.
DTC 421-426
High side to low side open
• DTC 421–426 is set by the ECM when the rising
time is too long for the open or close coil. DTC
421–426 usually indicates a harness or coil is
open.
• DTC 421–426 does not set the amber ENGINE
lamp.
DTC 431-436
High side shorted to low side
• DTC 431–436 is set by the ECM when the rising
time to 20 A is short, but not zero for the open
or close coil. DTC 431–436 usually indicates an
internally shorted coil.
• DTC 431–436 does not set the amber ENGINE
lamp.
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
DTC 451-456
High side short to ground or V
Each • DTC 451–456 is set by the ECM when the rising
The IDM time to 20 A is zero for the open or close coil. DTC
451–458 usually indicates the harness or coil is
shorted to ground.
• DTC 451–456 does not set the amber ENGINE
lamp.
Tools
• EST with MasterDiagnostics® software
• EZ-Tech® interface cable
• Digital Multimeter (DMM)
• Terminal Test Adapter Kit

INJ Pin-Point Diagnostics

injury or possible death, do not perform voltage
checks with the engine running. Injector solenoid
operating voltage of 48 V DC @ 20 A is present on
injector circuits.
CAUTION: To avoid engine damage, turn the ignition
switch to OFF before disconnecting the connector or
relay for the IDM. Failure to turn the ignition switch
to OFF will cause a voltage spike and damage to
electrical components.
Before doing injector diagnostic testing:
1. Turn the ignition switch to OFF.
2. Disconnect IDM connectors (X1 and X2).
All tests are checked at harness end. Pin numbers are
marked on all connector mating ends. After checking
resistance through injector coils and resistance to
chassis ground, if tests are within specification and
DTC is active, replace the injector.
NOTE: Only diagnose injectors with active DTCs.
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
WARNING: To avoid
BAT
serious personal