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2006 Gx 470 - Lexus Scanner Won't "talk" To Ignition/fuel


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All -Thank you in advance for any help/guidance.

I have a 2006 Lexus GX 470, that I drove through a street with about 2.5ft of ater the other day (there was no other option due to an crazy high tide coming up in downtown Charleston, SC).

This happened about a month ago. Afterwards I made it 500 yards and the car just powered off. While I was calling the tow truck (within 20 minutes), I was able to get it to crank back up. I drove it the next three weeks through Christmas without any issues. On Christmas I parked it and we drove our other car out of town. When I got back, it cranked for maybe 15 seconds, then died, and hasn't cranked since.

When I say it won't crank, all of the interior power and lights come on, but when you turn the key nothing happens. No clicking or anything such as a bad starter would cause.

I have taken it to the repair shop and they can't find the issue, and they tell me their scanner won't talk to my ignition, fuel injection, and I think emissions computer. They can talk to the ABS computer.

Any ideas on what we should be looking for? I am terrified I am being taken by the hour right now and the service manager doesn't sound all that confident.

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Hi Nathan and welcome to the Lexus Owners Club.

At first blush your problem seems to be a real head scratchier. When you say the repair shop can't read your diagnostic codes, I'm assuming your not talking about Lexus dealer. If this is the case, you can try anAuto zone store where they are usually very helpful.

However, to get the best results from downloading your codes, I would suggest trying you dealer for diagnostics, then check around town for prices.

I'm not an expert, however some things to check out might be the catalytic convertors. If they went through 2 1/2 feet of water it might be possible that they tool in copious amounts of junk. When a CC goes bad it can create a blockage that builds up exhaust pressure back to the manifolds. The car can come to a dead stop until fixed or, after driving just a short distance the car may just die.

Unfortunately, anything that was exposed to that much water could be a problem.


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The repair shop isn't the actual dealer, but they are a speciality import shop and say they have an identical code scanner. Some of the computer in the car are working and they can read them. The ignition and fuel injections ones just aren't "talking" to the scanners at all.

Thank you so much for you response.

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Nskipper001, the simplest solution would be to follow Paul's advice and go to an experienced car electrician if not to a dealer.

Otherwise, some thoughts for DIY:

- which error codes does the scanner report?

- check that the car's battery is OK

- check that the relevant fuses are not burnt out (consult your car's manual)

- check that the battery in the chip in your key is OK (consult your car's manual)

- if you installed non-OEM car alarm system/immobilizer, consult their manual/manufacturer

- disconnect the car's battery for 5 mins, reconnect it and repeat the scanning using the original OBD cable (it costs $400+ and many people prefer to use aftermarket cables, which often cannot connect to all systems)

If all this does not help, probably this is a hardware issue (presumably caused by a short-circuit) - something for a car electrician to diagnose further.

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Thanks again to you both. Wanted to try and clarify a couple of things to see if it helps.

1) the car is with a specialty Lexus/Toyota repair shop, with Lexus Master Certified technicians and they are using the Toyota Techstream scanner. At this point, I wish I would have gone straight to the dealership, but this shop has always worked on this car, and they felt like a responsible choice at the time.

2) They tell me they have checked all fuses and relay's, and the key.

3) They can't get any codes from the scanner. It basically doesn't see the ignition/fuel injection computers at all.

Couple of follow up questions. What is an original "OBD" cable and how can I tell them to make sure to use that? If that doesn't work, where do I find an actual car electrician?

Thank you again for all of your help and support.

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Nskipper001, so sorry that you are still having this trouble on the NY day. Re your queries:

(A) I am surprised that your technicians have "no error codes". I would expect some. Ask them to specifically confirm outcome of the "health check" procedure. I would assume that your situation should at least translate to some error codes. They may misinterpret the codes' meaning.

(B)The key is to follow the Lexus procedures for isolating and fixing the problem. You say that your current technicians have been trained as Lexus technicians. If so, they must have access to the comprehensive Lexus' repair manuals for your car and perform all the procedures as prescribed by Lexus. I would expect a discount from them (comparing to the Lexus dealers' prices).

(C ) Techstream is the right thing. I'd be almost positive that they use the original OBD cable. Though, if they are not "official Lexus", any extra cost-optimisation remains probable.

No point asking them to use the original cable - if they ever bought it, they must have tried it already. If they don't have it, you can only delicately verify this as a fact (if so, go to a Lexus dealer immediately).

The original cable is called Mongoose MFC (sample pictures here: old model & 2012+ model). Aftermarket cables often look exactly the same, but in most cases the brand name as shown on a device is misspelled (e.g. Mangoose instead of Mongoose etc.). Another test for counterfeit (though, a bit controversial one) is if the chip inside is not of the red colour (often, it's green on counterfeit).

(D) As to selecting a trusted electrician/technician, I am not in the US and will have to leave you here for someone's domestic advice (e.g. Paul's one above).


Re-read your original post -- a month and 3 weeks passed since the flooding (correct?), so probably no casual connection with your issue. It must be something else.

(1) If the car won't crank, just out of the blue, but the "ignition on" illumination is as usual, the most frequent cause is the dying battery.

From your original post, you may have been having all the symptoms of a dying battery over the last 2 months . E.g. if the car doesn't start immediately but would start after turning the "ignition on" for a while (i.e. giving a load on the battery to warm it up while it still has some reasonable juice), then the battery would re-charge from the alternator while you drive -- sufficiently enough to start the car next time, again and again, for as long as you use the car frequently. But if you leave the car parked for a week or more, all the juice from a dying battery may go away and it may no longer start the car. If the battery is not yet completely dead, you may be able to get the usual "illumination" with the "ignition on", maybe even put your headlights on, but the starter won't crank.

Drained batteries is the most frequent cause of no cranking. Once the battery is recharged, all should return to normal. Confirm that your mechanics positively confirmed the battery is OK with voltmeter (and confirmed that its physical terminals are OK). Asking them to in any event try re-scan the car with another (knowingly good) battery (lent from their stock) may be a good option.

(2) The second most frequent cause to no cranking is the burnt out fuses. You or your mechanics would need to isolate the fuses which might be responsible for the symptom. This is not a straight-forward exercise (though, my first guess would be to check IGN fuses). Testing the fuses may not be straight-forward, again (e.g. the fuses responsible for headlights appear dead unless you physically turn on the headlights). I've never had to check the IGN fuses but would assume you may need to similarly try to start the engine to properly check these fuses. Again, asking the technicians to just in case replace the fuses which may be suspected to be responsible for your issue with knowingly good ones, and re-scan the vehicle, may be a good opportunity. For this, they will likely charge you, but fuses are very cheap.

(3) Reflecting on my previous advice, if the key's transponder battery is dead, the starter should crank but the car won't start. On contrast, if you have a non-OEM alarm system/immobilizer and there's an issue with it, the car often will not crank.

(4) On another reflection, I don't know how the starter would behave if there's not enough fuel - check that you have fuel in the tank.

All in all, follow all the procedures that I prescribed. I hope it would resolve the issue. If not, please write back and we will try to help.

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Hi Nathan.

It sounds like your going to have to try a different avenue to track down your problem. At this point, having tried unsuccessfully to have your mechanics locate the problem with no success, I strongly suggest going to your Lexus dealer. They should be able to find away to read your codes. You can pay for a diagnostic session and find out the problem. The dealer will explain what the problem is and what it will take to fix it. At that time you can pay for the diagnostic session then go to your other mechanic for a consult and a second bid for the necessary repairs.

Don't get discouraged. Make a plan and follow it.


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