Briggs & Stratton VANGUARD 810 EFI Repair Manual page 49

Section 2: Troubleshooting DTCs
DTC P0174 Power Enrichment (PE) Lean Fuel Condition
Circuit Description
The PE mode is initiated in higher load run-
ning conditions. The ECM uses the MAP and
CKP sensor inputs to know when to go into PE
mode. PE fueling provides for optimal perfor-
mance and maximum power. It also prevents
against excessive exhaust valve and engine
temperatures.
Step
1. Check fuel fi lter and fuel lines for dirt, debris or
other restriction.
1
2. Is a problem found?
1. Check fuel pressure.
2
2. Is fuel pressure 38-43 psi (262-296 kPa)?
1. Verify that fuel fi lter is not clogged or restricted,
and that fuel pump is operating properly (see
3
Mechanical Diaphragm Fuel Pump or Electric
Lift Fuel Pump, Volumetric Test, in Section 5).
2. Is a problem found?
1. Check for vacuum and exhaust leaks.
4
2. Is a leak found?
1. Check for faulty fuel injector(s).
5
2. Are faulty fuel injector(s) found?
1. Replace faulty HO
6
2. Is problem corrected?
Scan and Non-Scan Diagnostics
Action
sensor.
2
Diagnostic Aids
If DTC P0174 is set, the ECM is detecting an
overly lean condition under heavy load.
Always clear DTCs after performing repairs.
Yes
Repair.
-
Repair.
Repair.
Repair.
-
45
No
Go to step 2.
Go to step 3.
Go to step 4.
Go to step 5.
Go to step 6.
Contact engine
manufacturer.