Dtc P0139: Secondary Ho2S (Sensor 2) Slow Response - Honda EP3 Service Manual

8 .
Check the secondary H02S (Sensor 2) output
voltage with the scan tool,
ls there 1.0 V ot mote?
YES-Go to step 9.
NO Replace the secondary HO2S (Sensor 2).1
Turn the ignition switch OFF.
Connect ECM connector terminals E2 and E4 with a
J U m p e r w r r e .
ECM CONNECTOR E 131PI
Wire side of female terminals
Turn the ignition switch ON (ll).
Check the secondary HO2S (Sensor 2) output
voltage with the scan tool.
ls there 1.0 V or more?
YES Update the ECM if it does not have the latest
soflware, or substitute a known-good ECM, then
recheck (see page 1 1-6). lf the symptom/indication
goes away with a known-good ECM. replace the
o r i g i n a l E C M . I
NO Repair open in the wire between the ECM (E2,
E4) and the secondary HO2S {Sensor 2).I
9 .
1 0 .
1 1 .
1 2 .
JUMPER WIRE
3 .
DTC P0139: Secondary HO2S (Sensor 2l Slow
Response
1 . R e s e t t h e E C M ( s e e p a g e 1 1 - 4 ) .
Start the engine. Hold the engine at 3,000 rpm with
no load (in neutral) until the radiator fan comes on.
Check the secondary HO2S (Sensor 2) output
voltage at 3,000 rpm with the scan tool.
ls thete 0.3- 0.8 V, fot 2 minutes?
YES Replace the secondary HO2S (Sensor 2).!
NO- lntermittent failure, system is OK at this time.
Check for poor connections or loose terminais at
the secondary HO2S (Sensor 2) and at the ECM.I
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