Briggs & Stratton BIG BLOCK EFI, Repair Manual

Page: 21 / 142

Section 2: Troubleshooting DTCs 17
Step Action Yes No
1
1. Disconnect and reconnect O
2
sensor and ECM J2
(Black) connectors.
2. Turn Ignition ON, Engine OFF.
3. Clear codes.
4. Turn Ignition OFF, and then back ON.
5. Does DTC return?
Go to step 2.
Problem
corrected.
2
1. Turn Ignition OFF.
2. Back probe (using fused patch cord) terminal A (Red
wire) on engine side of O
2
sensor connector.
3. Connect terminal A back probe to red meter test
lead on DVOM.
4. Back probe terminal D (Brown wire) on engine side
of O
2
sensor connector.
5. Connect terminal D back probe to black meter test
lead on DVOM.
6. Set DVOM to read volts DC.
7. Turn Ignition ON, Engine Off.
8. Does DVOM read 12.2-13.5 volts DC?
Go to step 3.
Perform visual and
continuity check of
Main Power Relay
and 20 amp
Battery fuse (Yel-
low).
Either there is no
power from fuse
block or not getting
ground thru 5 volt
return circuit.
3
1. Turn Ignition OFF.
2. Remove probe from terminal A, and back probe
terminal B (White/Green wire) on engine side of O
2
sensor connector.
3. Turn Ignition ON, Engine OFF.
4. Does DVOM read 12.2-13.5 volts DC?
Go to step 4. Replace O
2
sensor.
4
1. Turn Ignition OFF.
2. Remove probe from terminal B, and back probe
ECM connector terminal J2-07 (White/Green wire).
3. Turn Ignition ON, Engine OFF.
4. Does DVOM read 12.2-13.5 volts DC?
Both EFI wire
harness and O
2
sensor are good.
Go to step 5.
5
Are both O
2
sensor and ECM J2 connectors fully
mated?
Repair or replace
EFI wire harness.
Connect
connectors.
DTC P0031 Oxygen Sensor (HO
2
) Heater
Scan and Non-Scan Diagnostics
Figure 2-6 O
2
Sensor Connector. Figure 2-7 ECM J2 Connector (Black). Figure 2-8 Fuse/Relay Block.
Main Power Relay
Battery Fuse
1
9
10
18
J2-07
D C B A
A D B