Briggs & Stratton VANGUARD 810 EFI Repair Manual page 65

Section 2: Troubleshooting DTCs 61
DTC P0505 Idle Air Control (IAC) Malfunction
Scan Diagnostics
Step Action Yes No
1. Select the Dashboard ribbon and then the Main tab.
2. Observe Engine Speed display while idling.
3. Is reading 750-950 RPM?
Go to
IAC DTC P0505
NOTE: Cold engine temperatures and low battery voltages
1
circuit OK. Non-Scan
can cause high engine idle speeds. For example, at -18°
Diagnostics.
F. (-28° C.), idle speed can be as high as 1350 RPM, while
low battery voltages at normal engine operating tempera-
tures can cause the engine idle speed to reach 1200 RPM.
Figure 2-51 Check Engine Speed Display.