Briggs & Stratton VANGUARD 810 EFI Repair Manual page 34

30
DTC P0117/P0118 Engine Head Temperature (EHT) Sensor
Circuit Description
The EHT sensor uses a thermistor to control
signal voltage to the ECM. The ECM applies 5
volts on the sensor circuit. Sensor resistance
changes as ambient temperature changes,
which in turn affects the voltage return to the
ECM.
2
GREY
BROWN
J2 10
5 Volt
Return
Signal Voltage Low, High or Open
Section 2: Troubleshooting DTCs
EHT Sensor
1
GREY
Harness
Splice
TAN
J2 14
EHT
Sensor
Signal
ECM
Diagnostic Aids
Check for the following conditions:
1. Poor ECM connection. Inspect wire har-
ness connectors for backed out terminals,
improper mating, broken locks, improperly
formed or damaged terminals, and poor
terminal to wire connection.
2. Damaged wire harness and/or connectors.
If harness appears to be OK, shake or
wiggle wire harness and/or connector with
DVOM or ETA connected. Radical voltage
changes or a change in the EHT sensor
display can indicate the location of the fault
condition.
Always clear DTCs after performing repairs.