Air Injection Pump - How to
03-11-14, 10:38 PM
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Air Injection Pump - How to
Over the years, I've gotten some good info on this site for my GS300 and my wife's GX470. Definitely some good people on here, knowledgeable and very helpful. Here is my chance to contribute and pay it forward. 
So, my wife is coming home 2 weeks ago and the Check Engine, VSC Trac, VSC Off and the Anti- Skid lights come on and the car goes into Limp mode, basically, the vehicle won't move, RPM's would rise, but MPH doesn't increase and then finally it will kick into gear. Did some searches on here, some people mentioned replacing the gas cap would fix it. Got one, popped it in, disconnected battery to clear error. Great, everything looks like it works, lights off, and car drives normal. 2 days later, starting up in the AM to drop daughter to school, all lights come on again and limp mode. Took to my mechanic, asked to check it out and do an oil change while there (wife is not good about getting this done, guess I should be more proactive on this). Diagnosis, Air Pump or Air Injection codes came back, as well as bank1 02 and bank2 02 sensor codes. Based on some reading, these 02 sensor codes will come up if the air pump is not functioning properly, side effect, doesn't mean anything is wrong with them. Primary culprit here is the Pump. Quote to replace was $3500, which included $2500 in parts alone, Pump is $1274 and 2 valves that total another grand, then labor.
I jumped on the Club Lexus forum, surely someone had this problem and maybe had a cheaper fix or some alternative. I got some good info from RCsGX, Alan553 and Fantic that this damn pump is located under the Intake Manifold (WTH), as well as info on the Dorman Pump, which is similar and costs about $118 @ autozone, possibly cheaper online. Done, figured, I'd tackle the job myself, save some money.
So, my wife is coming home 2 weeks ago and the Check Engine, VSC Trac, VSC Off and the Anti- Skid lights come on and the car goes into Limp mode, basically, the vehicle won't move, RPM's would rise, but MPH doesn't increase and then finally it will kick into gear. Did some searches on here, some people mentioned replacing the gas cap would fix it. Got one, popped it in, disconnected battery to clear error. Great, everything looks like it works, lights off, and car drives normal. 2 days later, starting up in the AM to drop daughter to school, all lights come on again and limp mode. Took to my mechanic, asked to check it out and do an oil change while there (wife is not good about getting this done, guess I should be more proactive on this). Diagnosis, Air Pump or Air Injection codes came back, as well as bank1 02 and bank2 02 sensor codes. Based on some reading, these 02 sensor codes will come up if the air pump is not functioning properly, side effect, doesn't mean anything is wrong with them. Primary culprit here is the Pump. Quote to replace was $3500, which included $2500 in parts alone, Pump is $1274 and 2 valves that total another grand, then labor.
I jumped on the Club Lexus forum, surely someone had this problem and maybe had a cheaper fix or some alternative. I got some good info from RCsGX, Alan553 and Fantic that this damn pump is located under the Intake Manifold (WTH), as well as info on the Dorman Pump, which is similar and costs about $118 @ autozone, possibly cheaper online. Done, figured, I'd tackle the job myself, save some money.
Last edited by Zulfie; 03-12-14 at 08:30 AM.
03-12-14, 08:06 AM
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Hey Burny, took about 6 hours total. I did it across 2 days this past weekend. With this write up/documentation, it should take you about 4 hours or less. Alot of my time was spent fighting some tough connectors, figuring out the bolt in the back of the intake and the stubborn hose that goes from air valve #1 to air valve #2.
03-12-14, 08:09 AM
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Yea, crazy right, same exact motor and looking at the manufacturer's stamp on the body, believe it is the same company that makes both the Lexus/Toyota one and the Dorman one.
I saw it for as low as $89 online, but I couldn't wait, so paid the $118, still a lot cheaper than the $1274 Lexus wanted.
I saw it for as low as $89 online, but I couldn't wait, so paid the $118, still a lot cheaper than the $1274 Lexus wanted.
03-12-14, 10:00 AM
#7
Amazing work, Zulfie!
Thank you for sharing this with all of us.
Mods, Can we make this a Sticky??
Sounds like this problem can happen to any of us with aging GX470s.
It's sad that Lexus is charging so much money to fix something that in my opinion was not designed well on the first place.
On a side note, since i see the starter right there next to the pump, makes me wonder if it's a good idea, when and IF i have to replace the air pump, if i should also replace the starter as well....just in case.
Thank you for sharing this with all of us.
Mods, Can we make this a Sticky??
Sounds like this problem can happen to any of us with aging GX470s.
It's sad that Lexus is charging so much money to fix something that in my opinion was not designed well on the first place.
On a side note, since i see the starter right there next to the pump, makes me wonder if it's a good idea, when and IF i have to replace the air pump, if i should also replace the starter as well....just in case.
Last edited by danmm7; 03-12-14 at 10:04 AM.
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03-12-14, 10:10 AM
#8
Pole Position
Great writeup!
You are to be saluted for taking the time to document while in the process of doing that hard job.
Makes me glad I don't have an air pump!
You are to be saluted for taking the time to document while in the process of doing that hard job.
Makes me glad I don't have an air pump!
03-12-14, 10:47 AM
#10
Zulf, what about Air valves #1 and 2. Was there any apparent damage to those. Have you heard of any issues where they have to be replaced? When and if I ever go in there, I want to do it all including rebuilding my starter.
03-12-14, 03:10 PM
#12
Thanks for the write up Zulfie!!! Downloading and saving to my Lexus file for future reference should it be needed. Its crazy the amount of money that can be saved through this forum.
03-12-14, 05:56 PM
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None that I saw, I was able to test Air Valve #1, it opened and closed and I blew air thru and it passed un-obstructed.
Air Valve #2 is a pain to get to, buried under alot more stuff that I wanted to get into. Lexus does recommend replacing all three pieces, pump, air valve 1 and 2.
I had IM'ed Fantic to ask if he had replaced when he did the job, he didn't, but suggested to put a vacuum cleaner to the intake hose to Air Valve #2 and suck out anything that might have been in there. I did that.
Three days now and all is well, no lights and no drivability issues, so assuming nothing was wrong with #2.
If you do decide to remove, it looks like it comes apart in 2 pieces and might be easily fixed. I'm also assuming that it might have a plunger valve too, so if you applied 12V and it opens and closes, then it should be fine.