05 GX Bad ECM? Keep getting different codes

[Corndogger]

Hey Everybody. I'm new to the GX family (05 w 130K) and new to the forum. First, thanks to this forum as I was prowling a TON before I purchased mine recently and all the info I read really helped me pick what I hope is a solid rig. It spent its entire life in Memphis, one-owner, all service done at Lexus of Memphis except TB at 109K which was done at a local Toyota dealer. However, ever since I drove it home to Denver, CO, its been throwing CEL codes like crazy. The truck runs great, all regular maintenance done, been given a thorough once-over by my trusted local shop, new battery, just passed CO emissions with flying colors, so I'm stumped.

Here's a timeline of the Dates and Codes I'm dealing with. Is my GX struggling adapting to the altitude? Anyone else at altitude have these problems? Do I need to replace the ECM? I've read that is a very uncommon problem. Thank you in advance for any tips or pointing me to a previously solved problem. Note these are different codes each time, but a lot of them include the ECM as a potential problem.


Error Codes and Dates:

2-16-20 CEL
C1201 - Engine Control System Malfunction
Possible Causes:
-Sequential Multiport Fuel Injection (SFI) System Problems -Check for other codes

P0420 - Catalyst System Efficiency Below Threshold Bank 1
Possible Causes
-Faulty Three-way Catalyst Converter Bank 1
-Exhaust Tube
-Intake Air Leaks
-Faulty Oxygen (O2) Sensor
-Faulty Fuel injector(s)
-Leaking Fuel Injector (s)
-Faulty Spark plugs
-Improper Ignition Timing
-Faulty Engine Control Module (ECM)
-Dirty Air Filter

P0606 - Engine Control Module/Powertrain Control Module Processor.
Possible Causes
-Faulty Engine Control Module (ECM)
-Engine Control Module (ECM) Harness power supply circuit is open or shorted
-Engine Control Module (ECM) Programming

2-24-20 - Cleared Codes for visit to Emission Testing Center. (We have to pass in CO to register our cars)

2-26-20 - Passed Emissions w flying colors

2-28-20 - CEL
P2445
Possible Causes
-Air pump fuse Vacuum hose
-Air pump assembly
-Faulty Pressure Sensor
-Air pump harness is open or shorted
-Air pump circuit poor electrical connection
-Pressure Sensor harness is open or shorted
-Pressure Sensor circuit poor electrical connection

2-29-20 - Random - Put bottle of Techroline in gas tank because I don’t know how clean the injectors are and figured it couldn't hurt w 130K.

3-2-20 - Codes Cleared by themselves!

3-6-20 - CEL
P1442
Possible Causes
-Faulty Vacuum Switching Valve (VSV)
-VSV for air injection control circuit Bank 1
-Air Switching Valve Bank 1
-VSV for air injection system Bank 1
-Engine Control Module (ECM)

3/10 - Cleared codes w OBDII Scanner

4/6 CEL
P1445
Possible Causes
-Faulty Vacuum Switching Valve (VSV)
-VSV for air injection control circuit Bank 2
-Air switching valve No.2 Bank 2
-VSV for air injection system Bank 2
-Engine Control Module (ECM)

END!

 

[bigredmachine]

you need new air pumps and valves

 

[Corndogger]

you need new air pumps and valves

Thanks @bigredmachine. Any idea why some of the previous codes aren't returning? Why are they different each time? And, any other suggested preventative maintenance while I've got the manifold off and out of the way? 02 sensors?

 

[ZiaMan]

Google a guy named SlyFox75 and air pump bypass kit. You don't need to go through the whole ordeal of removing the manifold.

However, if you are going to remove the manifold, replacing/rebuilding your starter is highly recommended. Might as well upgrade the starter lead wire too. Google for 'Big 3' upgrade.

 

[Corndogger]

Google a guy named SlyFox75 and air pump bypass kit. You don't need to go through the whole ordeal of removing the manifold.

However, if you are going to remove the manifold, replacing/rebuilding your starter is highly recommended. Might as well upgrade the starter lead wire too. Google for 'Big 3' upgrade.

Thanks @ZiaMan. I'm going to look into all of that. A bit worried about bypassing the pump with emissions testing here in CO, but its nice to have that option. And a hell of lot easier fix than replacing.

 

[bigredmachine]

your getting different codes for the pumps because they haven't totally failed yet, if their intermittently working and the valve is getting stuck open or closed youll get different codes.

 

[CarolinaGX]

The secondary air injection system only works on startup until the cats get some temp. The hewitt kit is easy to install. I installed it on mine as a preventative measure.

 

[ZiaMan]

I would check to see what the emissions test actually involves - plug in only vs. plug in and visual inspection. Additionally you are assuming someone is going to notice 1 wire and 1 additional relay and know what it is. From a systems perspective, nothing would get flagged.

 

[Corndogger]

your getting different codes for the pumps because they haven't totally failed yet, if their intermittently working and the valve is getting stuck open or closed youll get different codes.

Thanks for these answers @bigredmachine - makes sense and very helpful.

 

[Corndogger]

Thanks @ZiaMan @bigredmachine and @CarolinaGX for the answers and tips. I ordered the Hewitt kit. For CO emissions they don't do visual inspections. Will replace the alternator and starter as preventative as well. Much appreciated guys.

 

[bigredmachine]

the pumps and valves fail due to getting water in the system due to pump pickup location and causing the valves to rust up and stick in place. they pretty much seize in the closed position as that's the position that they sit in the most

 

[bigredmachine]

I ordered the Hewitt kit

that would have been my first choice instead of replacing as the pumps and valves are very expensive list is around 2k for everything and it will fail again so theres that