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Ron, ASE Certified Technician
Category: Lexus
Satisfied Customers: 35515
Experience:  35 years working as an ASE certified tech.
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I have a 2005 Lexus GX470 that cranks fine but won't start.

Customer Question

I have a 2005 Lexus GX470 that cranks fine but won't start. Let me know when you are ready for the longer version!
JA: Tell me a bit more about what's going on so he can help you best. Are you hoping to fix this yourself?
Customer: Yes, trying to fix myself, but I acknowledge my limitations! Here is the longer version of where I am in this diagnosis:
JA: Great! What have you tried so far?
Customer: Hello, I have written this before logging in, thus its length so quickly.Summary: vehicle cranks fine, but will not start.Symptoms: I have a 2005 Lexus GX470, 120k miles, USA, Texas. Within the last few weeks, I purchased a new battery. Soon after, I got the red battery warning light, luckily in my driveway. I purchased a reman alternator and installed it. Light went away. Drove a few days, maybe 50 miles, no problems. Then, the other morning, I was driving and it cut-out some around 2.5k rpms, like it was dying, but then recovered with no problems. But if I tried to go much past 2k RPMs, it felt like it was trying to cut out. I figured it may be electrical or transmission. I made it home and parked it for a few days, with intent to do tranny flush this weekend and maybe spark plugs. Yesterday, I went to start it up, and it won’t start. It cranks very well, and all the other accessories seem strong, but it will not start. The starter will turn for about 5 seconds automatically but no hint at trying to fire.My checks: I have made sure the key transponder is working. The red light key symbol is not blinking when I try to start the vehicle. I checked battery voltage, 12.6V. I also charged it (recall it’s new), and it charged fine, but same start symptoms. Before disconnecting battery, I checked the OBD with a B**ch OBD 1100, and there were no codes, including no ABS codes. I checked all pertinent fuses in engine bay and under driver’s side dash…no blown fuses or fusible links. I checked pertinent relays (ign, fuel pump), and all seemed good. I own/maintain 5 Lexuses (1999 GS400, 2002 IS300 Sportcross, 2002 SC430, 2004 LX470, 2005 GX470), and this is a completely new experience that I have yet to figure out! So, any help is appreciated!!I have only owned this GX470 for just a few months, so I don’t know much past history. Carfax suggests it was maintained well at a Lexus dealership in north Houston.
JA: Lots of things can cause problems with the battery. The Lexus Mechanic will know what to do. Is there anything else the Lexus Mechanic should be aware of about your Lexus?
Customer: see my write-up, thanks.
JA: Our top Lexus Mechanic is ready to take your case. Just pay the $5 fully refundable deposit and I'll fill the Lexus Mechanic in on everything we've discussed. You can go back and forth with the Lexus Mechanic until you're 100% satisfied. We guarantee it.
Submitted: 1 year ago.
Category: Lexus
Customer: replied 1 year ago.
UPDATE: I believe I fixed it. For grins, I pulled out the fuel relay and tried starting it, just to see if any codes would be thrown. No start. No codes. So, I switched the Fuel Relay with the ACCessory CUT-off relay, and WOW! -- it started, but no more navigation screen nor stereo. So, then I swapped the DEFOG relay with the ACC CUT and now it starts, and navigation and stereo fully restored. Assuming I have no rear defroster, though. Thus, plan to purchase a new relay and call it fixed!
Customer: replied 1 year ago.
Also, I do NOT plan to try and collect any refund from this question, because I have used this site plenty in the past and have received helpful information in those cases. Consider it a $20 thank you for past work!
Expert:  Ron replied 1 year ago.

Hello, my name is ***** ***** I am a professional here at Just Answer. I have noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

In order for the engine to start and run you need good spark to the spark plugs, injector pulse, proper fuel pressure and good engine compression. In order to determine why it will not start you need to start first with determining which you are lacking. If you can get this done and post back with the results I will see if I can help you determine the cause.

Customer: replied 1 year ago.
Read my prior posts to determine how I fixed it. Thanks.
Expert:  Ron replied 1 year ago.

So you saying the problem has been resolved?

Customer: replied 1 year ago.
Replaced the fuel pump relay in the fuse box located in the engine bay by the battery. I have been driving the vehicle all week.
Expert:  Ron replied 1 year ago.

Okay glad to hear you got it resolved and thank you s well.