Engine Immobilization System

[ChuckJ]

My 05 SR-5 quite frankly has been the best truck I've ever owned..bought new, only 85k on it and has never been in the shop for more than routine maintenance, most of which I do myself anyway. The other morning I jump in, go to start it, it fires over, runs smooth for about 2 seconds and quits..not sputters, just like you turned the key off.. consecutive tries yields the same..check all the usual stuff, all ok..get out the code reader..no codes...all fuses and relays good..so I'm stumped..got (or had) fire, plenty of cranking power but it won't run..Think maybe fuel pump but have no codes..filter maybe, but no prior symptoms at all...so I decide to call the dealer..they usually won't say much but this guy says he'd bet on the MAF sensor or throttle body dirty.. ok, pull the MAF, looks fine, it's real clean but I change it for 85 bucks..I've never seen one go bad and not code out but I try anyway..nothing, same result.. clean throttle body, looks fine but clean it good anyway..nothing, same result..stumped again..so I go to lock the truck and hit the forums for info and notice the truck doesn't chirp when I lock it..the alarm isn't arming and the usually red blinking light on the dash isn't blinking.. hmmm do some research...there are references to a possible bad key chip..use a brand new original key that I keep in the safe..nothing..and no red flashing light when I pull it out.. sounding worse.. call the dealer, they say bring it in..have it towed in and get the dreaded call..the engine immobilization system appears to be fried, and apparently the ECU has to be changed out with it..entails pulling the whole dash out just to get to this thing..so I'm at their mercy.. initial estimate between 1500-2000 depending on if the amplifier (whatever the hell that is) is also shot, but they have never seen that..It does throw a code but its Toyota specific and only Toyota can read it (unless you have a high dollar reader like they have). Has anyone else had any experience with this system crapping out ?? What did it cost you ? Was the fix good ? It doesn't sound like a common issue but obviously a very expensive one with no good work around..the system apparently cannot be bypassed and still use the keys.

 

[A/V1]

I would get a second opinion from another dealership, just to see if they both lead to the same result. But if the ECU needs to be replaced, it won't be cheap. :wow:

 

[hoggy46]

I would get a second opinion from another dealership, just to see if they both lead to the same result. But if the ECU needs to be replaced, it won't be cheap. :wow:

I agree. When I put the remote start on mine, I forgot to put the key in the immobilizer bypass module. The truck would crank but wouldn't start at all. If the immobilizer was the issue, I would think it would do the same.

Ask them how they tested the ecu and determined it was bad? Sounds like they might just be throwing parts at it.

 

[BlackWorksInc]

[MENTION=122172]ChuckJ[/MENTION] That is a bit odd, since if the immobilizer didn't see the correct Key ID it would just crank over without firing (the injectors are cut off.) The fact that it starts and runs a short while is a bit odd.

I don't quite understand why the ECM needs to be replaced with the Immobilizer? What exactly is their reasoning behind that? The 4th Gen ECMs should be able to be re-seeded, unless their reasoning is that the Immobilizer fried the ECM?

Do you by any chance have a copy of their diagnostic notes that include the DTCs that they found out?

 

[ChuckJ]

Back on the road again !

Ok, so some good news...just got the car back... they pulled the dash apart to get to the immobilizer ECU (apparently I misunderstood that they might have had to replace the main ECM also)....anyway, immobilizer ECU checked out ok..the repair paperwork says they checked the terminal tension and found a loose/broken wire on the power lead..repaired that and it fired right up..This may make sense as when I came home Sunday there was road construction and where they had milled up the asphalt and it met the un-milled section there was about a 3 inch lip that wasn't tapered.. I didn't see it cause of the truck in front of me and slammed it really hard about 40mph....after that the truck wouldn't start again.. The bill was still $ 701.00, all labor time to tear down and re-install the dash and troubleshoot it. I can live with that.. I've had the truck for 10 yrs last month and it's never left me hanging, and all I've done to it was a new set of front calipers and routine maintenance.. so if if cost me 7 bills, that works out to 70 bucks a year for average repair costs.. I think the dealer could have really raped me bad if they wanted to so I consider myself lucky..Just glad it's back on the road again ! Dealer was Hendick Toyota of Wilmington (NC)

 

[the great him]

i have a 04 GX470(same thing just different coach) and with the 4.7l. anyhow when i bought mine in Dec i had it for less than 10days and my immobilizer threw a code. turns out i had a water leak from the windshield, that had gotten down into the wire harness and ran along into the main ECU where it shorted out, and proceeded to create a constant 2amp draw anytime the battery was hooked up(ie all the time). anyhow long story short my truck would do the same basic thing, get in, turn the key and just crank, no start, no codes. it would just continue to crank for about 10 sec even with the key released and me out of the truck...

took it to a Toyota dealer that my father inlaw works at, and it was the immobilizer code -just as he told me when he heard the cranking. but being a Lexus and in the computer system, Toyota couldnt help me so it was off to the Lexus dealer(some of the computer systems are specific, as the GX shows up as a Land Cruiser Prado 120, but the scan tool offers "no support" as the US never saw Prados). Lexus found and fixed my issue(i knew i had a water leak on the drivers side and the ECU is on the passenger side) -new ECU and wire harness repair as well as replaced the windshield. total cost was just under $2500 and problem was fixed.

i think you got the right and honest help/service for your issue. depending on where the wire was broken the dash should not have needed to be pulled as the main ECU can be replaced without removing the dash, but if the break was at the amp that is buried rather deeply into the dash and yeah it would have to get pulled. still i wish my bill would of only been $700. but still for me $2500 was fair, especially considering the new ECU was like $980+, and labor was $130ph and the new windshield was installed by a company that contracts with the dealer and came to around $350-400. sure i could of had it done for less some place, but this way it was all done at the dealer and if anything was wrong it was on them. so i dont feel my price of $2500 was unfair or a rip-off, but it did suck to have to pay that right after buying the vehicle.

 

[ChuckJ]

With regards to the immobilizer system in 2005 TR4 SR-5 does anyone know which fuse controls this system and is it located under the hood.. I can't seem to find a reference to it and don't want to start pulling fuses and throwing codes again... I assume its an ECU fuse unless its fused inline somewhere.. My truck is running fine again but I'd like to know for future reference which one it is (I did pull all fuses when I had my problem but none were blown) Thanks

 

[BlackWorksInc]

With regards to the immobilizer system in 2005 TR4 SR-5 does anyone know which fuse controls this system and is it located under the hood.. I can't seem to find a reference to it and don't want to start pulling fuses and throwing codes again... I assume its an ECU fuse unless its fused inline somewhere.. My truck is running fine again but I'd like to know for future reference which one it is (I did pull all fuses when I had my problem but none were blown) Thanks

It uses a branch off the 10A IGN and another branch off the 10A ECU-B fuses. I find it odd that a wire broke/pin had an issue due to a large shock; you'd think more of us off-roaders would have similar issues. I mean I jump and slam my 4Runner fairly hard when wheeling...

In any case, I'm glad they figured out what was wrong and fixed it. Though honestly I would have wanted to see the DTCs for the issue myself, but it's all fixed now.

 

[ChuckJ]

Thanks BlacksWorkInc, I probably should have asked for the code.. I do seem to recall him saying (I think) it was a B code, something that I couldn't read and didn't show on my meter.. I showed no code at all.. I know the wire/connection problem bothers me a bit too, I've bounced the truck around a few times with no problems..but my luck always runs that way, bizarre problems seem to follow ! But its running and they didn't rape me for an ECU, which they most certainly could have.

 

[the great him]

With regards to the immobilizer system in 2005 TR4 SR-5 does anyone know which fuse controls this system and is it located under the hood.. I can't seem to find a reference to it and don't want to start pulling fuses and throwing codes again... I assume its an ECU fuse unless its fused inline somewhere.. My truck is running fine again but I'd like to know for future reference which one it is (I did pull all fuses when I had my problem but none were blown) Thanks

there is no direct fuse. there is a hard mounted fuse, but you would have to disassemble the entire fuse block under the hood to replace/pull it. basically if the battery is hooked up, the ECU is getting power, even when the truck is turned off and the key is not in the ignition you could pull every fuse in both blocks and the ECU would still have power.

 

[BlackWorksInc]

there is no direct fuse. there is a hard mounted fuse, but you would have to disassemble the entire fuse block under the hood to replace/pull it. basically if the battery is hooked up, the ECU is getting power, even when the truck is turned off and the key is not in the ignition you could pull every fuse in both blocks and the ECU would still have power.

It's powered off the IGN & ECU-B fuses if you look at the EWD, which supply power to multiple modules in the vehicle.

 

[ChuckJ]

Well it does make sense to me "the great him" that power for this particular system Toyota would want to make as inaccessible as possible.. that's the way I was guessing. But BlackWorksInc you seem to be pretty sure the system is double fused, drawing power from two different legs...if that's the case should one of those two fuses go bad would the immobilization system shut down, or would it draw the power it needs from the other fuse, like a fail safe ? Just looking to learn something here in case I see it again, I can turn a wrench but I'm not well versed in the electronics. Thanks.

 

[the great him]

Oh I'm not saying that power does not come in via other sources, but even if you pull both of those two fuses, you will still have power to the ecu. The only way to eliminate power to the ecu is either remove the ecu from the system or pull the battery or pull the main power supply into the main fuse block. The ecu itself will have a circuit breaker inside. At least the on on my gx did and its a Toyota ecu. They make it the is way so that you cannot simply pull a couple of fuses and try to bypass the immobilizer. Its not possible without removing power, and if you remove power the vehicle won't work period.