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Discussion Starter · #1 ·
Hi Everyone,
Issue started happening after I replace my intake manifold gasket. I was careful to put every back into its place.
I thought it was a bad IAC and replace it. It started and idle but throw a P0100 and P0110. After idling and running for
5miles, car was very sluggish and won't shift on gear due due to Mass Air Flow Circuit goes into a safe mode. The next day, I attempted to start the car but it wouldn't start and noticed the EFI fuse keep blowing.
Schematic Font Rectangle Parallel Pattern


I've looked thru the forum and check a few things but nothing glaring out.
1. Isolate ECM -
2. Check Bank1 Sensor 2
3. Replace IDLE AIR control Valve
4. Throughout check the cables in the engine for short from 12V to ground.

I definitely have a short somewhere but I never had this issue before replacing the the intake manifold gasket
for an overheat problem.

Any ideas where I can check?
 

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Just for giggles, when you have the chance and it's light enough for you to see, find the diagnostic port under the hood (pass. side) and follow that right down to where it goes into the wiring harness. I had the same exact issue on a customer's car about 10 years ago and the wiring had rubbed through the loom and kept grounding on the car. Same thing happened to my 1st gen 2 years ago and it was a lot easier (quicker) for me to find this time. Let me know how and if this helps! Good luck!
 

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Discussion Starter · #3 · (Edited)
Thank you Ed. I measured the B+ and it's a short node there. Was the short you find inside the engine or on the passenger compartment near the ECM ? I checked the wiring harness around and on the top of the timing belt cover, nothing glaring. I've tried the wiggle test around the intake manifold and other places to see if I can get the voltmeter to read from 0 to 12V but nothing.
 

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I know this this is a completely different veh, but the premise is exactly the same and how I found the short(s) in both vans I described above. It would have been handy a decade ago for sure! Oh yeah, key off, black lead to ground on tester. When it beeps, then you know there's a short to ground. I'm sure you knew this already though! Hopefully I copied it to this page correctly!
 

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Seems to be somewhat common on 'Yotas for some reason, but not that prevalent...So keep me informed, if you will. Thank you
 

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Discussion Starter · #6 ·
Seems to be somewhat common on 'Yotas for some reason, but not that prevalent...So keep me informed, if you will. Thank you
Thanks Ed. I've got a meter on the B+ diagnostic port and another meter on the other end of the EFI fuse. They register and fluctuate between 1.9v-2.1v with the ignition key in the ON position. I did the wiggle tests around the cable harness from the ECM, on top of timing belt, connections isolated from the IAC, MAF sensor, IACV, Crankshaft position sensor, & around the alternator, .
Strange.

HoanM.
 

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I concur with circus. Double check ALL your wiring connections and grounds that you unplugged. Seems you missed something on re-assembly .
 

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Discussion Starter · #10 ·
I had to call a mechanic out. He found that the alarm system was bad and pulling the EFI fuse to blow. He removed the alarm and no more blown fuse. I looked thru the schematic but nothing was referred to the alarm using the EFI leg circuit.
 

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Jeez! That's friggin' CRAZY! I'm glad you/he figured it out though. I know it's all academic now (maybe disconnecting the battery caused this?), but I wonder if there was a way to reset the alarm instead of pulling it out? Anyway, thanks for letting us know the outcome!
 
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