** Need Help, 4Runner won't start

[dglee]

Need help. 2004 Limited, V6, it won't start, no cranking, no dimming of lights. Here's the story,...
1. Was running fine.
2. Took it in for full detail, including engine block clean (regret now).
3. VSC, ABS lights on about 3 weeks later.
4. Took it in to AutoZone, said I needed new wheel speed sensor, Front Drvr side.
5. Waiting for unit to arrive, then got CEL
6. Checked all wires, removed connectors to check, removed battery connections.
7. Then, CEL, VSC, ABS lights on and car won't start, turn over.
8. Replaced wheel sensor, performed Zero Point Cal, lights did not correspond to procedure, VSC lights never went out.
9. Checked all fuses, bench tested STA relay, tested ignition signal (less than 12V, was around 5.8v), hard wired 12v to trigger starter solenoid, it triggerred.
10. Checked continunity from STA relay terminals to solenoid trigger (good), checked hot side of STA relay (battery voltage).
11. Re-installed all connections, attempted ZPC again, same as before, CEL, VSC lights on (ABS light went out), no start, no crank, no dimming of lights.
12. Please advise. Sorry for long story, but wanted give history of what I've done.

 

[dglee]

Oops, jumped part of the story (#9 & #10), here's the sequence of events....
9a. Turned key to start/crank and measured 0v at ignition trigger to starter solenoid.
9b. Tested continuity from ignition connector to STA relay terminal #3 >> good.
9c. Bench tested STA relay @ 12v >> good with continuity at #3 & #5.
9d. Turned key to start/crank and measured 5.8v at coil position in fuse box with STA relay removed.
9e. Bench tested STA relay @ 5.8v and it triggered and tested continuity as well, good
9f. Hardwired 12v to solenoid trigger through its electrical wires to feel it actuate, it did.

Sorry for any confusion I may have inflicted.
Any ideas? I just got home a OBD scanner (loaner from AutoZone) and will try to get any additional codes later today.

 

[dglee]

Update: Couldn't get the scan tool to even link up with my 4Runner. I tried several attempts at it, even from disconnecting the battery, wait 15 minutes and re-connecting and trying again. Still no link from the scan tool to my vehicle. The lights all come on, then I'm left with VSC TRAC and ABS. They stay solid for about 20 seconds, then they both blink rapidly for about 2 minutes, then they both go out for about 10 seconds, then continue to blink rapidly together in sync. Anybody ever come across this? The battery has been charged, and I even left the battery charger hooked to it while attempting these tests.

Ideas? Anybody?? I'm lost.

 

[dglee]

No ideas anybody?? I'm going to try to direct wire the solenoid and at least see if the engine will crank. If that happens, then I'll start to really go thru the control circuitry and the ignition switch.

 

[mrpurplepenguin]

How certain are you that you reconnected _every_ connector and grounding point you disconnected in your Step 6? It sounds like your big troubles didn't start until after that step, correct?

It's interesting that you can't communicate with the ECU via the scantool - that means something isn't getting power / ground, or your ECU is dead. Since it's pretty unlikely your ECU decided to stop working at the same exact time you were disconnecting parts of the wiring harness, my first guess would be that something just didn't get hooked back up.

As for failure to crank, there's more to the circuit than just the keyswitch powering the starter relay - there's an immobilizer in there that's either a separate module or part of the ECU (I'm not sure), plus the control circuitry to keep it cranking automatically until it catches. I'd wait on hardwiring in a solenoid bypass until you know why you can't communicate with the ECU.

 

[dglee]

Hello MrPurplePenquin! Was starting to think I wasn't going to get any responses.

Well, I suppose I could have left something off, it wouldn't be the first time I'd sabotaged my own work. However, I have since gone over the wiring a few times, as I'm sort of OCD when it comes to this sort of stuff. But it wouldn't hurt to go over it again. Since the detail work, I have been trying to go over every connection that I could find (under the hood) that I think that cleaning wand might have had contact with. I did notice a very loose Emissions tubing that I then repaired. I will have to go over it again tomorrow or day after. Day light is pretty short nowadays after I get home from work and I don't have a garage to work in.

I have used the scantool on a 2005 Honda without any issues, so I know its not the OBD scantool from AutoZone.

Yes, I been able to find more of the wiring and starting to see more of the circuitry around the Starting/Cranking systems. I am wondering if I may have done some damage to the ECU by performing the ZPC after having the battery disconnected for some time. I did not have the scantool at the time so I was using just a wire to short out the OBD pins. Could I have shorted the wrong pins?? I honestly don't know. If I did, what kind of damage might I have caused to the ECU? Could I have inadvertently erased its settings? I don't know, but the CEL does come on when I turn the key (ECU is getting power), other lights (ABS) does go out after a few seconds (ECU must be doing something). I will check the OBD port for steady power the next chance I get and hold off on the solenoid bypass.

Thanks for your thoughts. Hopefully my ramblings will have spark some other ideas. I'll comment back when I have more news.

 

[BOSMECH]

It almost sounds like your key got deprogramed.

 

[Morphyne]

Ill admit I didn't read this thread very closely but from what I did read it seems like it is acting like my wife's van when it needed a new computer.

 

[dglee]

@ BOSMECH
Hmmm, I thought about that after reading other posts in the forum, so I tested it out by disconnecting the battery for 15 minutes (totally), reconnected and waited for 15 minutes and then attempted to start with the secondary key (not valet) and yielded the same results. Nice thought though, I'm glad I wasn't the only one to think of it.

So, today's events. It was raining when I got home from work, so it was already a dark and gloomy day, but I wanted to at least get some OBD port measurements. Betweem pins 4 and 16 I was getting battery voltage, 12.17v, and then between pins 4 and 7 I was getting 4.77v This was kinda low I thought and I had charged the battery this past weekend. So I started to do a parasitic drain test. After my setup I was measuring ~35mA, well below the 50mA that was considered acceptable. But since I had the setup already I just started pulling fuses to see the impact/effect. Everything was uneventful until I pulled the "dome fuse" then the current dropped to ~25mA. That was unexpected, I replace the fuse and went around the vehicle to see if I had any idiot lights on, >> none that I could see. I left it out and continued with my pulling from the engine block fuse box. When I pulled the "ECU-B fuse" out the current dropped to ~18mA. I replaced it and watched the current spike to about 130mA and then settled back down to ~18mA. Woo Hoo!! Did I just reset the ECU and now its behaving?? Well, I contained myself and continue on with the rest of the fuses in the box. The current stayed ~18mA.

I then proceeded to the inside fuse box and since I was there, I checked the OBD2 port again between pins 4 and 7 and was getting 5.17v. Woo Hoo!! That's a better voltage. But I continued to pulled the fuses from the inside box to complete the task and there was no other current movement. I left the "dome fuse" out and re-connected my main battery. I hooked up my scantool again with my fingers crossed.....and same darn thing, unable to link with my vehicle. Such a let down, guess it was too good to be this easy. I tried cycling the key a few times, didn't matter, no link. I re-measured the OBD port between pins 4 and 7 and was back at 4.77v.

Rain started to get heavy, so I will have to try again tomorrow with more measurements. At least I have no shorts and no parasitic drain on the battery. I'll have to hook up the charger again. So, after cleaning up and closing my doors, I tried the remote lock with my key and nothing. I put back in the "dome fuse" and voila! my remote door lock worked again. Funny how the "dome fuse" also actives the remote key door locks. I will have to look through the circuitry just to satisfy my huh? look.

Ok, so that's all I got, anybody with more suggestions/ideas??
Thanks for any offered help.

 

[dglee]

Last night I took the OBD port out to closely examine it and found no loose terminals, no terminals that can be pushed back when the scantool is inserted. I hooked up the battery charger and tried the scantool again. Still no link communication. The OBD port continue to give me battery voltage (13.2v) between pins 4 & 16, and this time, 5.4v between pins 4 & 7.

It looks like I have no choice but to really take each system circuit apart and verify all measurements per the "hints" in the FSM. I won't have time to look at this until the weekend. I'll start with "Start", "Ignition" and then hit ECU systems.

I've been reading the forums and other posts and get conflicting feelings about what may be wrong and like to post it here for others to review, perhaps someone can steer me in another direction.

1. ECU bad: Still could be true, but initial observations are (a) dash lights come on when key is turned to "ON" and then some lights go out, CEL, VSC and ABS stays on. After several seconds, VSC and ABS begins flashing, sort of gives me the notion that ECU is doing something. (b) getting 5.4v between ODB port pns 4 & 7.

2. Immobilizer Activated: When key (Master- black) is out, that light blinks (observed as normal operation). When key is inserted (as soon as it get close to ignition) light goes out. Tells me the transponder ECU is working (right?) cause the security lights goes out.

3. Starter: Still needs to be examine closer, as I stated in earlier post, I can hardwire the solenoid trigger and it engages. Have not tried to see if it can crank over the engine. And I did bang on it a few times with a hammer.

Ok, so that's it so far.

Stumped in NY

 

[riceandpho]

Is there an aftermarket alarm? Usually if you hit the unlock button on remote, see if you can get it to crank. This also work for factory installed security on other cars. People had drained the battery and used a key to unlock door, but forgot the security is still armed mode. Hitting the unlock might help you.

 

[dglee]

@ riceandpho
No, factory installed alarm, and I tried that as well anyways.

I hooked up my charger, set it for starting mode and tried starting again, no go. Now the fun begins....

 

[aeb28]

I just dealt with a starting problem that ended up being the neutral safety switch. I did not get any codes, just wouldn't start.

The switch was stuck on the transmission post, so I couldn't remove completely to clean the contacts without destroying part of the mount and needing a new switch. I ended up just removing the bolt that mounts the safety swith to the transmission so that it could pivot and cycle freely without affecting the tranny. I soaked it with some KRoil and then QD contact cleaner and cycled it a bunch of times. Worked like a charm...

 

[dglee]

@ aeb28
Thanks for your input. I googled this component and read other forum posts. So, I went back out and tried to start with the A/T in the neutral position, no dice. I tried again jiggling the positions, moving back to Park, back to neutral, etc. All times had the same non-responsive results. Is there a way to bypass this, or another way to test this out without taking things apart?

@ mrpurplepenquin
I re-checked all the connectors/connections/harness that I could get my hands on. Cleaned them and checked that all were re-connected and tight as best I can, no impact.

So now, here's my question... can I turn the key to the On position (not Start), remove the STA relay and then using the screw driver blade and hard jump 12v to the solenoid trigger without doing damage to any other systems? Even if the ECU is gone (suspect) I just want to see if the engine cranks over. This will prove that the starter motor and power cables are good. I've seen this being done from other forums and YouTube. Seems like a good test. Let me know your thoughts.

Thanks.

 

[aeb28]

In my case, starting in different gears worked maybe once or twice, but then it went completely dead. Starting in neutral didn't do anything, the vehicle just would not start.

Now that I know what I know, doing it again would be quick and easy. If you turn your wheels all the way to the left, you can look through the passenger side wheel well and see the switch on the side of the transmission. All you would need to do to clean it the way I did is unbolt the 12mm bolt at the top, and disconnect the plug. I would also remove the retainer nut (7/8ths) on the transmission shaft to allow better penetration of contact cleaner. I never removed the switch or took anything apart aside from one nut, one bolt, and the plug. Would take me 10-15 minutes to do it again if need be. I did not need to remove the wheel or jack up the car. I am 6' 1 and 190, it is tight but I got in there with relative ease. If you have gone this far, it wouldn't hurt to give it a try before throwing money at parts.

I too researched bypassing it as a last resort. I found a few discussions on other vehicles regarding splicing some of the wires on the plug. I wouldn't do it without a thorough understanding of the wiring diags, there is not a lot of room to correct any mistakes. I would probably play it safe and replace the switch before I started screwing around bypassing things.

Hope this helps, good luck.

 

[dglee]

I appreciate your thoughts and indeed it wouldn't hurt and I like the idea of playing it safe. I'll have a look see this weekend.

I also did send an inquiry to my local toyota service dept and ask for suggestions and got back a response that the ignition switch or ignition lock cylinder would be places of interest.

 

[dglee]

Finally had a chance to do some more troubleshooting. Found a blown zener diode in the ECU. Now having a hard time locating information about it and where to buy one. Anybody know of this component and where to get a few?

Its in location D409 and has these markings, D.4 3G
Thanks for any info anybody can provide.

 

[BlackWorksInc]

The problem is that you probably can't repair the ECM at this point.

There's a few things to consider:

-Identifying the Diode may be extremely difficult as it will not be listed by Toyota and you'd have to find a parts list for the original company that supplies Toyota with the ECM boards (honestly, good luck with that.)

-The diode may have burned out the substrate underneath (I don't have a picture so I can't see how bad the burn is) which may have affected the printed circuits in ways you can't easily see.

-If the burn is bad, it would make re-soldering it that much more difficult (typically ECMs are sealed to help with corrosion/moisture.)

-Even if you did manage to replace and correctly solder the new diode into the ECM board and get the ECM functional, there's no guarantee that the ECM memory/BIOS is not severely damaged/corrupted. I'm not entirely sure if it would be possible to even flash it with a TIS Techstream.

I'm not saying don't try, just that I have known a few people who have tried to repair other brands of modules and it doesn't always work out the way you think it will.

Post Note-

The other thing to consider is that if it did burn a diode that means there is/was a voltage/current issue with the vehicle that back fed into the ECM; that's something to keep in mind as you diagnose the vehicle because it may fry the next ECM down the line if it isn't addressed.

 

[DanielMaat89]

If It's a blown diode, you can get them from digikey, radioshack or element14. I would use a diode tester to test some of the other diodes in the ECU. At this point, what do you have to loose. Just be careful de-soldering the old one and installing the new one. Too much heat will destroy the circuit board. They use multiple layers on these boards and too much heat will cause them to warp and cause other problems.

 

[dglee]

Yep, I understand the slim chances but at this point what do I have to lose? A new one would cost 1k, then add in reprogramming, taxes and whatever the stealership intend to top it off with, verses 2 bucks for a diode some solder and my time. Even ECU repair services state that not all ECU can be repaired, however, just to get the ECU diagnosed to determine that runs about $200 bucks. So, let's see what happens if I just replace the diode, only issue is finding the correct part to replace it with. I already know that this is just one issue, cause I still have the other issues to debug (VSC & ABS originally).