P0430 Code

Back in January I had a buddy help me (I'm not as mechanically inclined) replace a valve cover gasket on my 2006 Toyota Tacoma (4.0L V6 2WD). While we were in there we decided to use the opportunity to also replace the following items which I picked up at Advance Auto Parts:

• Denso SK20HR11 Iridium Long Life Spark Plug (Part No: 3421)
• Felpro Intake Manifold Gasket Set (Part No: MS 96671)
• Intermotor PCV Valve (Part No: PCV550)

For the sealant on the valve cover gasket we used Permatex MotoSeal 1 Ultimate Gasket Maker Grey (Part No: 29132). We had ordered an OEM valve cover gasket from a Toyota distributor but ended up with 2 of the same parts instead of the mirrored versions of it so we ran to Auto Zone and picked up a gasket set they had in stock. He was able to find the Toyota replacement manual for that job which we went by for the work. The only thing I can think of that we didn't do was disconnect the battery. Anyways, we replaced all the parts and also cleaned the Mass Air Flow sensor (using MAF cleaner) but when we finished and started up the truck it had 4 codes show up (no previous codes before the work):

• C1241 - Low Battery Positive Voltage
• P0102 - Mass or Volume Air Flow Circuit Low Input
• P0113 - Intake Air Temperature Circuit High Input
  
• P0430 - Catalyst System Efficiency Below Threshold Bank 2

It was late so I drove home (about 30 miles) and was thinking the MAF sensor we cleaned might be my problem (or some ramification from not disconnecting the battery) but there seemed to be no engine issues and no loss in power. After the truck was shut off and sat in my driveway and I started it back up the check engine light was gone. I thought my problem was done with. After a few days it came back on with the same 4 codes and then after a day or two it would go off. Eventually all the codes dropped off and the only remaining code I currently have is the P0430 which would come on for a week and go off for a week (sometimes more, sometimes less). Lately it seems to be staying on more and I hesitate to take it to a shop (I typically use Firestone) or a dealer because I think they'd start replacing the most expensive items first if they felt it was justified. Back in August I used some Motor Medic Fuel Injection System Treatment (it was while the code happened to be off) and it stayed off for about a week and a half. I've been thinking about using some

$29 Cataclean 120007 Complete Engine, Fuel and Exhaust System Cleaner, 473 Milliliter (Packaging May Vary)

Cataclean Catalytic Converter Cleaning Treament but I don't know if that would help or not. There are a lot of variables with this code and it makes it hard to find an easy solution (plus I'm not set up to do a lot of truck repair myself) so I guess I'm looking for any advice people might have before I take it somewhere for repair.

Thanks!

 

I'll bite;

I would start by verifying you have a sound charging system and battery, alternator output should be ~14.0 volts plus, and if the battery is in question, have it tested or replace it.

Next, those 3 other codes CAN be caused by an air intake/vacuum leak, and since you messed around with the intake gasket, double check your work - Replace the gasket again if necessary and use an OEM gasket set.

Also double check the MAF sensor and connector, it could also be a wiring issue.

Crawl under the truck and inspect the exhaust system for corrosion or leaks (even a pinhole leak) near the O2 sensor for bank 2 (P0430). Doesn't take much of a leak to skew the sensor readings.

May want to double check all the grounds and wiring you messed with in the original repair, could be as simple as a loose/left OFF ground connector.

After you've double checked and/or repaired everything, do a hard reset. Disconnect the battery and touch the cable ends together for 15 minutes. Reconnect and test drive.

Report back when you're DUN.

 

The original 3 codes are gone and have been for several months so I'm mostly just worried about the P0430 code which is still hanging around. I had Auto Zone check my battery right after they pulled those codes for me and it was good at the time. I'll try to check for a pinhole leak around the exhaust system when I get a chance. We did check all the grounds and wiring after we finished the repair and went back over them all to double and triple check after we saw that check engine light. I haven't disconnected the battery to date but I have reset the codes with my code scanner a couple times. Do you think that would do the same thing or should I still try disconnecting the battery to see if that works (longterm)?

 

Go to Google and key in:

Tacoma P0430

Also Google -> P0430 Intake Manifold - a number of hits on manifold gasket as mentioned by Jeffs68