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Home >> Suzuki >> 2002 >> XL-7 Plus >> Repair and Diagnosis >> External Pages >> Different car >> Section 6 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0401: Exhaust Gas RECIRCULATION Flow Insufficient >> Diagnostic Procedure
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Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Isuzu Trooper. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform ON-BOARD DIAGNOSTIC II SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD-II system check, go to next step.
  2. If DTC P1404 is also set, go to DTC P1404: EXHAUST GAS RECIRCULATION RANGE/PERFORMANCE STUCK VALVE . If DTC P1404 is not set, go to next step.
  3. Start engine and allow to idle. Using scan tool, monitor MAP signal. Quickly press throttle half way down and release. If MAP value made an immediate large change, go to step  6. If MAP value does not make an immediate large change, go to next step.
  4. Replace MAP sensor. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM.
  5. Inspect exhaust system for modifications or leaks. If a problem is found, repair as necessary and go to step  8. If no problem is found, go to next step.
  6. Remove EGR valve and check pintle, valve and passages and adapter for excessive deposits or restriction. If problem is found, go to step  8. If no problem is found, go to next step.
  7. Remove EGR inlet and outlet pipes from exhaust and intake manifolds. Inspect manifold EGR ports and pipes for blockage. If a problem is found, go to next step. If no problem is found, check for an intermittent problem. See DIAGNOSTIC AIDS .
  8. Read and record FAIL RECORDS data for DTC P0401. Clear DTCs. Start engine and monitor system information screen while moving connectors and wiring harnesses related to EGR valve. If scan tool displays DTC P0401 FAILED THIS IGNITION, go to last step completed in this DTC test. If scan tool does not display DTC P0401, repair is complete.
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