Honda 2004 Odyssey Service Manual page 428

DTC P0131 '01 Model:
(Sensor 1) Circuit Low Voltage
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 primary HO2S (Sensor 1) output voltage
with the scan tool or the HDS during acceleration
using wide open throttle.
Does the voltage stay at 0.5 V or less?
YES Go to step 4.
NO Intermittent failure, system is OK at this time.
Check for poor connections or loose terminals at
the primary HO2S (Sensor 1) and the PCM.
4. Check the fuel pressure (see page 11-216).
Is it normal?
YES Go to step 5.
NO Repair the fuel supply system.
5. Turn the ignition switch OFF.
6. Disconnect the primary HO2S (Sensor 1) 4P
connector.
7. Turn the ignition switch ON (II).
8. Check the primary HO2S (Sensor 1) output voltage
with the scan tool or the HDS.
Does the voltage stay at 0.5 V or less?
YES Go to step 9.
NO Replace the primary HO2S (Sensor 1).
9. Turn the ignition switch OFF.
10. Disconnect PCM connector A (31P).
Primary HO2S
11. Check for continuity between primary HO2S
(Sensor 1) 4P connector terminal No. 1 and body
ground.
PRIMARY HO2S (SENSOR 1)
4P CONNECTOR
PHO2S (WHT)
Wire side of female terminals
Is there continuity?
YES Repair short in the wire between the PCM
(A6) and the primary HO2S (Sensor 1).
NO Substitute a known-good PCM and recheck
(see page 11-5). If the symptom/indication goes
away, replace the original PCM.
11-119