Navistar International DT 466 Diagnostic/Troubleshooting Manual page 480

476 7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
Do Injection Control Pressure Test.
Test ICP system for leaks.
DTC 334 – ICP unable to achieve set point in time (poor performance)
DTC 334 indicates an injection control system response time fault and may be set during normal engine
operation through the continuous monitor function or during the KOER Standard Test.
DTC 334 compares measured ICP to desired ICP and looks for a large pressure difference of 9.5 MPa
(1378 psi) for a period of 3 seconds.
When DTC 334 is active, the ECM ignores the ICP sensor and controls the IPR valve operation from
programmed default values.
Possible causes for DTC 334 include the following:
• Low oil level in crankcase
• High oil level in crankcase
• Contaminated engine oil
• Debris in engine oil
• Aerated engine oil
• Trapped air in the ICP system (particularly after an injector or high-pressure pump replacement)
• Intermittent IPR valve wiring connection. Inspect engine wiring harness connector and IPR valve
terminal for corrosion. Inspect terminal for bent or pushed back pins.
• Inoperative or stuck injection pressure regulator
• Leaks in ICP system
• Problem with ICP sensor or sensor circuit, incorrect sensor, system biased high or low
• Inoperative high-pressure hydraulic pump
Checks and Tests
Check repair history – Determine if
trapped air caused by ICP system
disassembly.
Check oil level and quality.
Check active and inactive DTCs.
Do ICP Operational Voltage Checks.
Do IPR Pin-Point Diagnostics.
Do KOEO Standard Test.
Do KOER Standard Test.
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Verify if oil is aerated at high idle. See "Performance Diagnostics"
– Section 6 (page 205).
See "Hard Start and No Start Diagnostics" – Section 5 (page 143).
Comment
If ICP system was serviced, vehicle should be operated 20 miles
to validate system performance
Check oil level, API classification. Inspect for debris. If
contamination is suspected, check oil filter element.
Repair any ICP sensor codes. See"ICP Sensor" (page 457).
Check KOEO pressure sensor value and voltage. See "ICP
Sensor" (page 457).
Test will verify IPR circuit continuity. See "IPR" (page 494).
Test will verify IPR circuit continuity. See "Performance
Diagnostics" – Section 6 (page 205).
Test will verify major ICP system failure. See "Performance
Diagnostics" – Section 6 (page 205).
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.