mickrussom

I would like those with experience or thoughts to comment on this problem I am having. Many thanks in advance for any thoughts or commentary on this, it is a very frustrating error given that the car performs well and the tailpipe emissions are within limits.

** Background:
- Well maintained 2001 Maxima 20th, regular oil, oil filter and air filter changes. Always used Mobil-1 5W-30.
- California VIN/SPEC.
- 125,000 miles
- Power, acceleration and performance good.
- No smells or other oddities
- KN air filter installed to try an improve airflow if that is an issue.
- Lucas octant booster and fuel injector cleaner being used over a few tanks of gas to try and get this high mileage car happy again

** Maintenance to-dos:
- Coolant flush just performed to try and combat P1126. I have been neglecting the coolant flushes.

- Need to do plugs, replacing with NGK Laser OE. Will do to try and combat P0430 (TWC trouble-shooting guide says plugs may be suspect. Will do soon. (Should have been done at 105,000).

** More information
- Recent long trip to San Diego on Route 5 at 80+ MPH in 100 deg F heat caused MIL/SES to TURN OFF. I should have done inspection right after it did that. Oh well, missed the chace, the MIL/SES is back on.

- I noticed the heater output is on the weak side. This could be a clue involving P1126. The heater isn't blazing hot when set to 90F.

- I took the vehicle to Nissan Dealship, and they said the ECU TSB that is for P0420 reprogram (involving ECU and MAF reprogramming) does not apply, and all ECU TSBs are up to date. I personally did not like their service at the $tealership, but I needed to try as they have Nissan tools that can read more from the ECU/ODBII than the normal ones.

MIL/SES light on. Codes being pushed are P1126 and P0430.

- Trustworthy tech said oxygen sensors in February flutter pre and post cat properly. So I do not believe the O2 sensors are broken. But a flaky post cat sensor could be the root cause here.

** Possible fixes to consider:

- Replace thermostat (I'm guessing if the 180F thermostat is not working, things would get ugly quickly)
- make sure water pump is working (I'm guessing if this was failed things would get ugly quickly)
- make sure coolant temperature sensor is working (gauge seems to work on the dash)

- Replace Bank 2 Pre-cat, gasket.
- Replace Bank 2 Pre-cat (post TWC) sensor)
- Use an O2 simulator to stop this bloody nonsense.
- Get a complete CATTMAN system and forget this whole thing, at $1200, it’s a relative bargain to replacing. However, I would like to pass smog-check and believe this would not pass.

** Out of warranty
- 8 year / 80,000 warranty cannot be applied and begging at $stealership didn't work. Extended warranty expired.

** Dealership madness?
Dealership claimed that if pre-cat is bad, that the engine could "ingest" bits of the honeycomb. Is this true? Why would this be the case? Dealership wanted to replace all post cat oxygen sensors, the two pre-cats and the cat to "fix" P0430. I believe that is total overkill for this situation. Cost to fix ~$2000.

** Who can I go to in the SF Bay Area to get this fixed at a reasonable cost? I would intend on using Nissan parts but want the work done by someone who doesn't charge arm and leg book times which are way too long.

----------------------------------------------------------
The ESM states for P0430:
P0430 - Three Way Catalyst Function (Bank 2)

Description:
Catalyst system efficiency below threshold

What Set The SES Light Off:
Warm-up three way catalyst does not operate properly, warm-up three way catalyst does not have enough oxygen storage capacity.

Possible Causes:
Bad 3-Way Catalyst
Exhaust Tube
Intake Air Leaks
Injectors
Injector Leaks
Spark Plugs
Improper Ignition Timing

OutMaxxed

iTrader: (7)

for the P0430 code...i just replaced my cat. Its the one right infront of the radiator. Cost me about 190$ for the part. I had it put in yesterday. No complaints yet. Here is the link to my thread.
http://forums.maxima.org/5th-generat...urus-step.html

There should be a link to the website to purchase that badboy. Good luck

mickrussom

California: I had P0430 and P1126. The following actions solved the problem for me:

1st tank of gas:
- 44K injector cleaner
- Lucas Octane Booster
- Lucas Fuel Treatment

2nd tank of gas:
- Lucas Octane Booster

- Did oil change
- Replaced plugs with NGK OE Laser Iridium IFR5E11 7994
- reset ECU (unplug battery while changing plugs)
- Coolant flush (To address P1126)

Drove the car after ECU reset in the manual's driving cycle:
* Start engine cold.
* Run engine idle after starting for 10 minutes (get to operating temp).
* Drive from 0 to (53-60) MPH with a steady foot.
* Release accelerator for 10 seconds
* Drive (53-60) with steady foot for 11 minutes
* Stop for 10 seconds
* Accelerate from 0 to (30-35) with a steady foot within 10 seconds
* Drive (30-35) for 20 seconds
* stop, repeat this 5 times.
* Accelerate from 0 to (53-60) and drive for 5 minutes.
* Turn off engine.

Went to California smog station, 7 out of 7 ECU readiness diagnostics set/passed.

Passed smog in California.

Seems that the P0430 code can be caused by many things other than the three-way-catalyst (TWC) (pre-catalytic-converter) being bad. The service manual indicates a trouble shooting procedure that arrives at blaming the TWC last.

Falore Nissan in Sunnyvale California is a dishonest bunch of criminals. www.falorenissan.com - 680 E. El Camino Real Sunnyvale, CA 94087 (408) 735-6888. They said P0430 would be to replaced all oxygen sensors and all cats for $2500. They determined this in literally 2 minutes after using a code reader on the ODB link. They didn't even use the Nissan-specific computer system. (CONSULT II).

Download the service manual for your Nissan or infinity here:
http://www.boredmder.com/FSM/Infiniti/
http://www.boredmder.com/FSM/Nissan/

Mine was:
http://www.boredmder.com/FSM/Nissan/...MPLETE-FSM.zip

The manual is fairly well written about diagnosing certain codes. Check with this before going to the $tealership.

cabernet

Thanks for the writeup. In the Bay Area here too and same P0430 code. Cleared the code but car still runs rough. Code hasn't gone back on after 600 miles though. Will try some of your fixes. I wish there was a $190 pre-cat for the California Maximas but they are illegal and can't be sold or mailed to this state. Have to buy OEM at about $800 for just the part.

I also had the 1126 code this year. The thermostat was stuck open. If your car isn't heating up in 2 or 3 minutes or runs cold on the freeway you might want to try replacing the thermostat.

mickrussom

Thanks, I think I'll do the thermostat. Was it hard to replace?

I am very disappointed by the cost of the TWC precat. The best price I have gotten was from a parts store (directnissanparts.com). The service manual also indicates there is a gasket that needs to get replaced at the time of servicing.

I'm buying a ODB-II scanner (equus 3160) and will continue to try to fix problems like these because its considerably cheaper than going to a dealership.

sontakke

Your rough running has absolutely NOTHING to do with P0430. Do you have any other code pending or set? If there is already a code, the car does not run necessary monitor test for the catalytic converter. If your OBD has no pending code and all of your monitor tests are shown as "OK", for the last 600 miles, you have nicked the P0430 problem.

For rough running, you can probably start with the basics like MAF cleaning, spark plugs, air-filter, strong fuel system cleaner etc.

- Vikas

cabernet

Thanks. Have replaced air filer and will try fuel cleaner. Rough engine starting same time P0430 came on. That's been the only code for the last 10,000 miles. It's stayed off. The car isn't too rough until I turn on the AC and then it gets really bad.

sontakke

If the car is running that rough, you might be running on 5 cylinders :-( That would be very bad. But if that is the case, computer should give more codes. Is your scanner good enough to give multiple codes? Is car shaking at idle? What is your idle speed?

If it is still running on all cylinders but little rough, go for strong dose of fuel system cleaner. Double dose it. Techron, Gumout Regane, Redline SI-1, BG44K are the recommended ones. Stay away from rest of them like STP or Prestone or house brands. While at Walmart/autostore, pick up new air cleaner element. It is cheap and takes less than 30 seconds to replace it.

If that does not show any improvement, next would be cleaning MAF. Next would be spark plugs and/or coils.

- Vikas