Engine no crank no starter operation?

Tiny
DAVE REGNEY
  • MEMBER
  • 2005 TOYOTA COROLLA
  • 1.8L
  • 4 CYL
  • 2WD
  • MANUAL
  • 46,125 MILES
A friend just dropped this off at my place. Car has no crank, no start. Upon further investigation I noticed the 100 amp alt fuse blown, dome light fuse blown and AM2 blown. Replaced fuses and the same thing.

If I put new fuse in and turn IG to on, I briefly get brake, ABS, BATT, TPMS and airbag lights on dash before fuse blows.

Went back and rechecked fuses and AM2 is blown again. Hooked up light to am2 and performed the following:

Unplugged coil packs
Injectors
unhooked ALT
P/N switch
Only way I can get light to come off is to pull 30A main in engine compartment.

What components are powered by the AM2? What else should I check/pull to find this dead short?
Thursday, November 21st, 2019 AT 9:54 AM

5 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,867 POSTS
Hi,

The AM 2 fuse is for ignition and fuel and a few other things. I suspect that if you remove the AM2 fuse and replace the main fuse, the starter will engage.

Now, the first thing I want you to do is pull the FI relay under the hood and place another relay in its place and see if that fixes the issue. If it does, replace the relay.

If that isn't the issue, remove the plastic cover from the valve cover. Inspect the wiring harnesses in the rear of the engine. Are any saturated with oil? Next, there is a large wire bundle in a wire loom toward the passenger side rear of the engine. It isn't uncommon for the harness to rub through a wire mount and short. Inspect the wiring harnesses and move them around and away from anything it can short on. Replace the fuse and see if it blows. If it doesn't move the harnesses again and see if that causes it to blow.

I attached a pic below that shows what this fuse powers. There are things in the list specific to engine model.

Do this and let me know if any of it helps.

Take care,
Joe
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Friday, June 25th, 2021 AT 5:03 PM
Tiny
DAVE REGNEY
  • MEMBER
  • 4 POSTS
Replacing the 30a main does no good, still blows. Go relay good, checked out even swapped = same am2 short.

I believe am2 blowing will not let Ecu engage starter relay. As the check engine light, ABS, TPMS, brake light and airbag warning lights are in this system and with the check engine not being lit will not allow car to start. With that being said, I unhooked starter also. Am2 still shorted. Replaced ignition switch with no changes.

If ignition is in the ON position, fuse blows, this leads me to believe there is a dead short. What circuits feed off of this? I’ve searched in vain for this info along with the pin out of ignition switch to see if there’s a wire hot that shouldn’t be.
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Friday, June 25th, 2021 AT 5:03 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,867 POSTS
I attached a few pictures below. The first 4 are the test procedure for the ignition switch. They show what each pin should have as far as resistance.

The last four pictures are a schematic showing power to the switch and power out. I overlapped them so you could read them.

Let me know if this helps.

Joe
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Friday, June 25th, 2021 AT 5:03 PM
Tiny
DAVE REGNEY
  • MEMBER
  • 4 POSTS
Started trouble shooting, got over to the passenger compartment and there was a strong smell of fried electronics. Unplugged ECU, replaced AM2 fuse = no blow. Warning lights now light up on dash. Ordered a new ECU. Will update once it arrives.
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Friday, June 25th, 2021 AT 5:03 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,867 POSTS
Ugh! That isn't good news. Here are the directions for replacement. Make sure the new one is plugged in before you reconnect the battery.

______________________________________________________

2005 Toyota Corolla L4-1.8L (2ZZ-GE)
Electronic Control
Vehicle Service and Repair Procedures Electronic Control
ELECTRONIC CONTROL
ELECTRONIC CONTROL

pic 1

a. REMOVAL AND INSTALLATION OF BATTERY TERMINAL
1. Before carrying out any work on the vehicle electronics, disconnect the battery negative (-) terminal cable to prevent component and wire damage caused by accidental short circuits.
2. When disconnecting the terminal cable, turn the ignition switch and lighting switch OFF and loosen the terminal nut completely. Perform these operations without twisting or prying the terminal. Remove the battery cable from the battery post.
3. Clock settings, radio settings, DTCs and other data are erased when the battery cable is removed. Before removing the battery cable, record any necessary data.

Pic 2

b. HANDLING OF ELECTRONIC PARTS
1. Do not open the cover or case of the ECU unless absolutely necessary. If the IC terminals are touched, the IC may be rendered inoperative by static electricity.
2. To disconnect electronic connectors, pull the connector itself, not the wires.
3. Be careful not to drop electronic components, such as sensors or relays. If they are dropped on a hard surface, they should be replaced.
4. When cleaning the engine with steam, protect the electronic components, air filter and emission-related components from water.
5. Never use an impact wrench to remove or install temperature switches or temperature sensors.
6. When checking the resistance of a wire connector, insert the tester probe carefully to prevent terminals from bending.

_________________________________

I hope this helps.

Take care and let me know if you need anything. Also, if I don't hear from you, have a great Thanksgiving.

Joe
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Friday, June 25th, 2021 AT 5:03 PM

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