Navistar N9 Diagnostic Manual page 31

1 DIAGNOSTIC TROUBLESHOOTING PROCEDURES
Step 1 Perform preliminary operational checkout procedure.
Did you perform 1.0 Preliminary Vehicle Operational Checkout Procedure?
Step 2 Determine if injector buzz test will identify a failed injector.
Perform Injector (Buzz) Test (page 2154).
Is an audible buzz sound heard from each injector?
Step 3 Check for no start related Diagnostic Trouble Codes (DTC).
Using Electronic Service Tool (EST) with ServiceMaxx™ software, check DTC list for:
• SPN 94 Fuel Delivery Pressure (FDP)
• SPN 931 Electric Fuel Pump (EFP)
• SPN 164, 3055 Injection Control Pressure (ICP)
• SPN 679 Injection Pressure Regulator (IPR)
• SPN 636 Camshaft Position (CMP)
• SPN 637 Crankshaft Position (CKP)
• SPN 108, 158, 628, 629, 1136, 1387 Engine Control Module (ECM)
• SPN 27, 2791 Exhaust Gas Recirculation (EGR)
• SPN 110, 1659 Engine Coolant Temperature 1 (ECT1)
• SPN 175 Engine Oil Temperature (EOT)
• SPN 51, 3464, Engine Throttle Valve (ETV)
• SPN 651-656, 2797, 2798, 3055, 3659-3664, 4257 Injector (INJ) faults
• SPN 4287 Engine Compression Brake Pressure (ECBP)
Does EST DTC list have any active fault codes listed above?
27
Decision
Yes: Go to Step 2.
No: Go to 1.0 Preliminary
Vehicle Operational
Checkout Procedure
(page 23).
Decision
Yes: Go to Step 3.
No: Do injector circuit
diagnostics (SPN
651-656 FMI 4, 5; SPN
2797, 2798 FMI 3, 4;
SPN 3659-3664 FMI
4, 5) for specific failed
injector(s). If circuit
diagnostics passes,
replace failed injector(s).
Decision
Yes: Go to Fault Code
Diagnostics for no start
related SPN.
No: Go to Step 4.