Briggs & Stratton VANGUARD M490000, Repair Manual

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DTC P0174 POWER ENRICHMENT (PE)
Circuit Description
The PE mode is initiated in higher load running
conditions. The ECM uses the MAP and CKP sensor
inputs to know when to go into PE mode. PE fueling
provides for optimal performance and maximum power.
It also prevents against excessive exhaust valve and
engine temperatures.
If DTC P0174 is set, the ECM is detecting an overly lean
condition under heavy load.
Diagnostic Aids
Always clear DTCs after performing repairs.
DTC P0174 Lean Fuel Condition (Non-Scan Diagnostics)
Step Action Yes No
1 1. Check fuel filter and fuel lines for dirt, debris or other restriction.
2. Is a problem found?
Repair. Go to step 2.
2 1. Check fuel pressure. See CHECK/RELIEVE FUEL SYSTEM
PRESSURE in SECTION 5 - REMOVAL/INSTALLATION.
2. Is fuel pressure 38-43 psi (262-296 kPa)?
- Go to step 3.
3 1. Verify that fuel filter is not clogged or restricted, and that fuel
pump is operating properly (see Mechanical Diaphragm Fuel
Pump or Electric Lift Fuel Pump, Volumetric Test, in SECTION 5 -
REMOVAL/INSTALLATION.
2. Is a problem found?
Repair. Go to step 4.
4 1. Check for vacuum and exhaust leaks.
2. Is a leak found?
Repair. Go to step 5.
5 1. Check for faulty fuel injectors.
2. Are faulty fuel injectors found?
Repair. Go to step 6.
6 1. Replace faulty HO
2
sensor.
2. Is problem corrected?
- Contact engine
manufacturer.
Not for
Reproduction