202 5 HARD START AND NO START DIAGNOSTICS
NOTE: When using the EST to do KOEO or KOER
diagnostic tests, Standard Test is always selected
and run first. If the ignition switch is no t cycled, the
Standard Test does not have to be run again.
8. From the KOEO Diagnostics menu, select Glow
Plug/Inlet Air Heater, then select Run to start the
test.
9. Record results on Diagnostic Form.
• If both relays are not operational, confirm that
the E CM is program med and enabled for the
Inlet Air Heater.
• If both relays are not operational and the
ECM programming is correct, do the following
checks in “IAH S ystem ” – Section 7:
— Actuator Voltage Checks at ECM (page
449)
— Harness Resistance Checks – Relay t o
ECM (page 450)
— Harness Resistance Checks – Relay t o
12–pin Connector (page 450)
• If voltage is not B+, do the following checks in
“IAH System” – Section 7 :
— Harness Resistance Checks – Relay to
ECM (page 450)
— Harness Resistance Checks – Relay to
12–pin Connector (page 450)
If the c ontrol circuit wiring to the relay is
correct, replace relay.
• If voltage is B+, verify p revious test results.
Check wiring from th e re lay t o e lem e n t.
The wiring may have continuity and low
resistance. However, a poor crimp, loose
connector, or co rrosion could preven t ability
to handle circuit load.
Possible Caus es
• Failed wiring harness or connection
• Poor ground connection
• Failed relay
• Failed element
• Failed ECM
• ECM not programmed (inlet air heater)
EGES-270-1
Read all safety instructions in the "Safety Information" section of this manual before doing any proced ures.
Follow all warnings, cautions, and notes.
©August 2008 Navistar, Inc.
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