Briggs & Stratton BIG BLOCK EFI, Repair Manual

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14 Section 2: Troubleshooting DTCs
Verify ECM Powers Up
Circuit Description
Since all EFI components are dependent on
proper operation of the ECM, any diagno-
sis must include checking ECM power and
grounds.
Remove and clean battery terminals. While
terminals may appear clean, corrosion on the
inner surfaces can cause a poor connection to
ground.
NOTE: When the ECM is powered up, you
may hear the fuel pump module prime for two
seconds. This is not defi nitive proof that the
ECM is getting proper voltage.
Step Action Yes No
1
1. Turn Ignition OFF.
2. Back probe terminal J2-18 (Red wire) of ECM J2
(Black) connector.
3. Connect terminal J2-18 back probe to red meter
test lead on DVOM.
4. Connect black meter test lead on DVOM to a
known good ground.
5. Set DVOM to read volts DC.
6. Turn Ignition ON, Engine OFF.
7. Observe voltage on DVOM.
8. Is reading 12.2-14.5 volts DC?
Go to step 2.
Look for open or short
to ground in battery
(B+) feed circuit.
Perform visual and
continuity check of
15 amp Ignition fuse
(Blue).
2
1. Turn Ignition OFF.
2. Remove probe from terminal J2-18, and back
probe terminal J2-15 (Red wire) of ECM J2 con-
nector.
3. Connect terminal J2-15 back probe to red meter
test lead on DVOM.
4. Connect black meter test lead on DVOM to a
known good ground.
5. Turn Ignition ON, Engine OFF.
6. Observe voltage on DVOM.
7. Is reading 12.2-14.5 volts DC?
Go to step 3.
Look for open or short
to ground in ignition
feed circuit.
3
1. Turn Ignition OFF.
2. Remove probe from terminal J2-15, and back
probe terminal J2-02 (Black wire) of ECM J2 con-
nector.
3. Connect terminal J2-02 back probe to red meter
test lead on DVOM.
4. Connect black meter test lead on DVOM to a
known good ground.
5. Set DVOM to read resistance.
6. Observe reading on DVOM.
7. Is resistance 1.0 ohm or less?
Go to step 4.
Look for open or short
in ECM ground circuit.
Check ECM Power and Grounds
Scan and Non-Scan Diagnostics
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