Dtc P0138: Secondary Ho2S (Sensor 2) Circuit High Voltage - Honda S2000 Service Manual

DTC P0138: Secondary HO2S (Sensor 2)
Circuit High Voltage
1. Reset the Eclvl (see page 1 1-41.
2. Start the engine. Hold the engine at 3,000 rpm with
no load (in neutral) until the radiator fan comes on.
3. Check the secondary HO2S {Sensor 2) output
voltage at 3,000 rpm with the scan tool.
Does the voltage stay at 0.6 V or more?
YES Go to step 4.
NO Intermittent failure, system is OK at this time.
Check for poor connections or loose terminals at
the secondary HO2S (Sensor 2) and at the ECM. r
4. Turn the ignition switch OFF.
5. Disconnect the secondary HO2S (Sensor 2) 4P
connector.
6. Connect secondary HO2S (Sensor 2) 4P connector
terminals No. 1 and No. 2 with a jumper wire.
SECONDARY HO25
ISENSOR 2l ilP CONNECTOR
SG2 IGRN/YELI
SHO2S IWHT/RED)
Terminal side ol male terminals
JUMPER WIRE
7 .
8 .
1 0 .
Turn the ignition switch ON (ll).
Check the secondary HO2S (Sensor 2) output
voltage with the scan tool.
ls there 0.6 V or more?
YES Go to step 9.
NO Replace the secondary HO2S (Sensor 2).1
Turn the ignition switch OFF.
C o n n e c t E C M c o n n e c t o r t e r m i n a l s C 1 5 a n d C 1 8
w i t h a j u m p e r w i r e ,
ECM CONNECTOR C (31PI
JUMPER WIRE
{WHT/RED}
SG2 {GRN/YELI
1 2
3
l u l u l
9 1 0
l 3
1 4 1 7
1 8 20 21
6
26
n
n
a
30
Wire side of Iemale terminals
1 1. Turn the ignition switch ON (lll.
12. Check the secondary HO2S (Sensor 2) output
voltage with the scan tool.
ls there 0.6 V or morc?
YES Substitute a known-good ECM and recheck
(see page I 1-5). lf the symptom/indication goes
a w a y , r e p l a c e t h e o r i g i n a l E C M . I
NO - Repair open in the wire between the ECM
( C 1 5 , C 1 8 ) a n d t h e s e c o n d a r y H O 2 S ( S e n s o r 2 ) . 1
sHo2s
1 1 - 5 9