Briggs & Stratton BIG BLOCK EFI, Repair Manual

Page: 29 / 142

Section 2: Troubleshooting DTCs 25
Circuit Description
The MAT 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.
Diagnostic Aids
Check for the following conditions:
1. Poor ECM connection.
2. Inspect wire harness connectors for backed
out terminals, improper mating, broken
locks, improperly formed or damaged termi-
nals, and poor terminal to wire connection.
3. Damaged wire harness and/or connec-
tors. 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 MAT sensor
display can indicate the location of the fault
condition.
Always clear DTCs after performing repairs.
DTC P0112/P0113 Manifold Air Temperature (MAT) Sensor
Signal Voltage Low, High or Open
MAT/MAP
Sensor
ECM
MAT
Sensor
Signal
3
J2 08
TAN/BLACK
4
5 Volt
Return
J2 10
BROWN
MAP
Sensor
Signal
1
J2 11
WHITE/RED
5 Volt
Reference
2
J2 16
RED/WHITE