Honda 2004 Odyssey Service Manual page 434

DTC P0138 '99-00, '02-04 Models:
Secondary HO2S (Sensor 2) Circuit High
Voltage
NOTE: Information marked with an asterisk ( ) applies
to '02-04 models.
1. Reset the PCM (see page 11-4).
2. Start the engine. Hold the engine at 3,000 rpm with
no load (in Park or neutral) until the radiator fan
comes on.
3. Check the secondary HO2S (Sensor 2) output
voltage at 3,000 rpm with the scan tool or the HDS.
Does the voltage stay at 1.0 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 the PCM.
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 HO2S
(SENSOR 2) 4P CONNECTOR
JUMPER WIRE
SG2 (GRN/BLK)
SG2 (GRN/YEL)*
Terminal side of male terminals
7. Turn the ignition switch ON (II).
SHO2S (WHT/RED)
8. Check the secondary HO2S (Sensor 2) output
voltage with the scan tool or the HDS.
Is there 1.0 V or more?
YES Go to step 9.
NO Replace the secondary HO2S (Sensor 2).
9. Turn the ignition switch OFF.
10. Connect PCM connector terminals A23 and C18
(A1 and C18) with a jumper wire.
PCM CONNECTORS
SHO2S
(WHT/RED)*
A (32P)
SHO2S (WHT/RED)
JUMPER WIRE
SG2 (GRN/BLK)
SG2 (GRN/YEL)*
Wire side of female terminals
11. Turn the ignition switch ON (II).
12. Check the secondary HO2S (Sensor 2) output
voltage with the scan tool or the HDS.
Is there 1.0 V or more?
YES Substitute a known-good PCM and recheck
(see page 11-5). If the symptom/indication goes
away, replace the original PCM.
NO Repair open in the wire between the PCM
(A23, C18) (A1, C18) and the secondary HO2S
(Sensor 2).
JUMPER WIRE
C (31P)
11-125