Help!!! P1444 P0138 P0139 P0158 P0159

[grantguo]

My 2000 Infiniti I30 has the following engine OBD-II code:
P1444 Canister Purge Volume Control Solenoid Valve
P0138 02 sensor circuit high volts (bank 1 sensor 2)
P0139 Heated Oxygen Sensor 2 Circuit Slow Response (Bank 1)
P0158 Heated Oxygen Sensor 2 (Rear) (Bank 2) (Max. Voltage Monitoring)
P0159 Heated Oxygen Sensor 2 (Rear) (Bank 2) (Response Monitoring)

The P1444 turns on in only about 10 miles after reset.
The rest of the codes appear in about 50 miles.

I have already replaced the Canister Purge Valve, the Downstream sensor in the rear manifold and the Gas Cap.
But the code stay the same, nothing changed.

Anyone can give me some clue?
The car otherwise runs great.
The codes have been there for almost a year, but now I need to pass smog check.

One thing may worth to mention is that the engine light first turned on after a heavy rain day when the rear part may contact with water.

Many thanks.

[jem003]

Repairing the evap [gas vapor] system is common after warranty.
Low US gasoline quality and road dirt/dust plugs up vent system.
Just turning light off will fail because the ecu/car must be driven ~~ 50 miles with multiple starts and accelerations to 55 mph to reset and prove the emission are actually okay.
Repair the defects is the only method.


*P0138 02 sensor circuit high volts (bank 1 sensor 2)
The rear heated oxygen sensor (or sensor 2), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank.Even if switching characteristics of the heated oxygen sensor 1 are shifted, the air-fuel ratio is controlled to stoichiometric, by the signal from the heated oxygen sensor 2.This sensor is made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions.Under normal conditions the heated oxygen sensor 2 is not used for engine control operation.

*P0139 Heated Oxygen Sensor 2 Circuit Slow Response (Bank 1)
Possible Causes:
- Harness or connectors (The sensor circuit is open or shorted)
- Rear heated oxygen sensor (Bank 1) may be faulty
- Fuel pressure may be faulty
- Injectors may be faulty
- Intake air leaks may be faulty


*P0158 - O2 Sensor Circuit High Voltage (Bank 2 Sensor 2)
- Injectors may be faulty
- Intake air leaks may be faulty
- Exhaust gas leaks may be faulty
- PCV valve may be faulty
- Mass air flow sensor may be faulty

*P0159 - O2 Sensor Circuit Slow Response (Bank 2 Sensor 2)
- Injectors may be faulty
- Intake air leaks may be faulty
- Exhaust gas leaks may be faulty
- PCV valve may be faulty
- Mass air flow sensor may be faulty

[loystock]

All of your codes are related to water immersion. And it's not a good idea to operate a car with bad O2 sensors for extended period as the engine tends to run richer which can damage the remaining O2 sensors, and worse, the expensive catalytic converters (3 each - Bank 1 and Bank 2 Pre-Cats and Main Cat).

For P1444, check all the tubings to/from the Evap Canister (back of the car near gas filler tube) for cracks or loose connections. Make sure you label each tubing before disconnecting it as wrong installation can create more problem. Most likely a cracked or loose tubing allowed water ingestion, clogging the lines with water. Remove any water from the system. Replace/tighten the affected tube.

As for the O2 sensor problems, they can easily get damaged by water. There are 4 sensors and most likely the lower 2 sensors (Rear sensor, downstream of respective Pre-Cat) were immersed in water. These REAR O2 sensors (HO2S2-B1 with WHITE harness1 & HO2S2-B2 with RED harness) have 4-wire connectors mounted near the radiator. The HO2S2-B1 sensor is mounted in front of Bank 1 Pre-Cat (horizontal mounting) while HO2S2-B2 is mounted on the vertical section of the pipe, downstream of Bank 2 Pre-Cat. There is no O2 sensor for the main cat. BTW, Bank 1 is towards the firewall while Bank 2 is towards the radiator.

Safely jack up the front pax side (use jack stand) and once under the engine, follow the exhaust pipe and look for the WHITE and RED harnesses leading to the respective sensor. Use a liberal amount of WD-40 or PB Blaster and use an O2 Sensor Adapter (@ $10, long socket with opening on the side) during removal/installation.

You have a choice of using the OEM Bosch sensor (expensive @ $150), the OEM-compatible NGK/NTK sensor(@ $90) or Universal (<$50 but requires splicing and knowledge of wiring diagram. Our NICO sponsor, NGK.com, a.k.a. "sparkplugs. com sells these O2 sensors , P/N: 24572 and 24574 for @ $90 each. See link below. If you are lucky, you can get it cheaper from Amazon.

http://www.ngk.com/results_app.asp

Once you have fixed the problem you have to complete the SRT (System Readiness Test) in order to pass SMOG check. I can give you instructions on how to do this but if you have a scanner, it will tell you which parameters are READY or NOT READY. In CA we are allowed a maximum of 2 NOT READY sensors, provided CEL is off and emission requirements are met, to pass the test.