one more thing, instead of checking the fuse for continuity, change to volts and make sure the fuse gets power on both sides. because if the fuse is good and the ign relays dont work, then you can lose power mirror, turns/hazards and start.

 

still dont see how the stop light dont work. that doesnt need ign, eng, or any of that. you sure you dont just have a bad stop light? ive heard of vehicles wired that the stop light goes out, then no start because using the same circuit

 

Thx guys,

ill check all relays and swap the meter over to volts. Novice here.

hard to know if a single bad stop light is the culprit, as they had been working just prior to non start issue

greatly appreciated

 

https://www.richmond.com/richmond-dr...603d77298.html

not sating this is the case, i havent looked at the wiring for the gx.

 

doubtful its just the stop, i think those are led. but the switching and power to that circuit is a must have to start.
its a simple circuit to check. voltmeter from the brake switch to ground. one side should activate with the pedal press. also make sure that the switch is adjusted properly. had a honda 2 weeks ago the switch button hits a plastic insert. the insert broke so the switch button wasnt hitting anything.

 

Still no definite answer on the battery voltage under load. I have screwed up before and misplaced some fuses and multiple systems started shutting down while driving, audio system, navigation, climate system and eventually a full shut down.
Misplaced fuses were in the cabin fuse box.

I pulled all all fuses and reinstalled in a restaurant parking lot and got a jump-start with no problems after that.

My point here is, Start with the battery, as a weak battery may give you some functions but not able to start the truck.

 

Well, I charged the battery outside of the car to 14.2 last night. tried it again today and it did not start. Post attempt, the battery measured at 12.5V. Though at 14.2, the accessories did not have power.

Every fuse/relay has been checked. Strangely, I was able to start the car using the "place the key fob to start button method last night" as I was pressing the button for 10 seconds or more and then releasing. This only worked once. With the vehicle started, I still did not have power to door locks, rear lights, radio, Nav, power seats, etc. I was unable to repeat this result once the car was turned off.

The battery voltage did not appear to rise up to quickly and did not get to 13 when running. The Alternator may be a factor. Perhaps the ECU is fried as well.

When placing the battery on a load test meter, it measured fine in "the green".

 

Have you run any diagnostics on it like Techstream? OBD Fusion/Link should work as well..


https://www.clublexus.com/forums/gx-...and-gx460.html

If you purchase the OBD BT adapter linked to Amazon in that thread you can freely download the OBD Link app.

 

Hi Acrad,

Thanks for the tip. That's next on my list. My FIXD smart phone OBD tool does not work as there is no Power to the port to allow for diagnostics. Perhaps one of the manual tools would work better and not require the port to be powered.

 

Unfortunately if accessory mode won't even turn on not much chance to pull codes.

How long have you had this vehicle? If purchased used anything show up in Carfax or Lexus service history related to the electrical system?

 

Thanks, Purchased new, 08/2014. first ever problem we've experienced.

 

Both FOBS exhibit the same behavior? any 3rd party alarms installed?

Wonder if it could be some odd stock security alarm/ignition immobilizer issue?

Do you have factory remote start?

 

By FOBS, are there 2 OBS diagnostic ports? Nothing 3'rd party added. No factory remote start. Could be the alarm/ignition issue noted.

 

EDIT: Does you OBD port still have power with vehicle off? Normally It should.

On FOBs I meant both keys. Have you had any water leaks around the windshield?

Only one OBD port.

Purely speculation but if ECU related might be one of these two. This is a tough one as you'd almost have to follow wiring diagrams step by step and actually power test all relays as well.

 

No water leaks... Thanks very much for your time and the diagrams. I'll print and take a look tonight.. Ahh, Key FOB's.. right, sorry!! Same issue with both key FOBS


Is the ECU on the interior on the passenger side?