ECU codes preventing 4wheel drive?

[Hambone]

I own a 2011 SR5, 105,000 miles and I've had 4x4 issues intermittently lately and the system has just quit working all together. My 4x4 indicator light blinks continuously regardless of transfer case lever position. 4 wheel high doesn't engage thus 4 low doesn't either.

Toyota dealer told me a wheel speed code was showing, wanted $140 to just diagnose further. I replaced two front wheel speed sensors and harnesses for much less. Same issue remains.

I've taken the truck to a local mechanic who specializes in imports. He's telling me that the power steering ecu is throwing a code that is preventing troubleshooting from progressing. However he is working with Toyota to update his scanners to get past this hurdle but says the power steering ecu code could be preventing 4wheel drive activation.
Has anyone experienced anything remotely similar?




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[Jeremy556]

Is it blinking fast, like 2x speed it flashed between selecting 4wd and it engaging, when 4wd worked? If so, check the plug to the ADD on the front axle, that it is fully engaged.

Mine looked like it was plugged in, but it wasn't quite fully plugged in and would randomly refuse to engage or disengage the ADD, with a resulting fast 4x4 blink until I cycled the ignition. I pulled the connector and got that same fast 4x4 blink at all times. Fully plugged it back in, and haven't had an issue since.

It never stored any codes of any kind and didn't throw any errors in Techstream, even when it was happening. I would recommend getting a cable and techstream off of eBay if you want to diagnose and fix things yourself.

 

[Hambone]

Thanks, I'll look into those systems. First I've heard of those(I do have a ScangaugeII). I had recently checked the plug at the ADD to verify current but will double check. To answer your question it is the fast blink.


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[1engineer]

Paging [MENTION=66389]BlackWorksInc[/MENTION]

 

[Jeremy556]

Thanks, I'll look into those systems. First I've heard of those(I do have a ScangaugeII). I had recently checked the plug at the ADD to verify current but will double check. To answer your question it is the fast blink.


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Scangauge really just does OBD2 stuff. Techstream is what the Toyota dealer uses and does far, far, more.

If you're sure it is plugged in fully, I would start checking continuity of the ADD actuator itself and wiring between it and the 4x4 module.
https://dl.dropboxusercontent.com/u/7660835/4wd_add_inspection.docx

 

[BlackWorksInc]

Not sure... I'd have to look into that.

Do you have the DTCs written down somewhere?

 

[Hambone]

Not sure... I'd have to look into that.

Do you have the DTCs written down somewhere?

They're telling me C1547 is the code.


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