Possibly fried the computer after putting my Multi-meter to the plug and ground to the engine block

Tiny
GLEVI1127
  • MEMBER
  • 2013 CHEVROLET EQUINOX
  • 2.4L
  • 4 CYL
  • 4WD
  • AUTOMATIC
  • 135,000 MILES
I had a slight misfire sometimes while idling so I decided to check the plugs and the PCV valve since I read on some forums that the PCV hose was known for getting plugged. Once I was done with the plugs and put the coils back on I could hear a clicking noise coming from one of the coils randomly every couple minutes. Me being the genius that I am decided to put my multi-meter to the plug and ground to the engine block and I believe I may have shorted out the computer. I have an obd2 3100i scanner and it now shows most of the car's components are in the red when they were all green before and the car runs way worse. I didn’t even take it out of the garage. Do I need a new PCM? I messed up and now I need help please!
Monday, February 17th, 2020 AT 2:10 PM

11 Replies

Tiny
JOETECHPRO
  • MECHANIC
  • 705 POSTS
Hey GLEVI1127,

The first step will be to check all of the fuses in the under hood and interior fuse box.

There is a guide in the link below to check and replace fuses:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Start with this and let us know what you find.

It is amazing how many electrical faults can be traced back to a blown fuse.

Best of luck.

Regards, Joe
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Monday, February 17th, 2020 AT 2:17 PM
Tiny
GLEVI1127
  • MEMBER
  • 7 POSTS
Okay, I’ll see what I can find and get back to you. Thank you
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Monday, February 17th, 2020 AT 2:19 PM
Tiny
GLEVI1127
  • MEMBER
  • 7 POSTS
I seem to be getting all kinds of odd readings. Dash lights on but no keys in the ignition I got.09 on the ECM 02 sensors and ignition fuses. I also heard what I think were the ignition coils clicking randomly. Then with the keys in I got point 06 or 07 volts coming through those five fuses. I’ve double and triple checked my ground and the battery on my multi-meter. I think I have a short some where don’t I?
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Monday, February 17th, 2020 AT 3:04 PM
Tiny
GLEVI1127
  • MEMBER
  • 7 POSTS
Also my battery shows 11.6 volts and the car hardly started like the battery was nearly dead. And the emission light that went red when this all happened are. Fue, egr, cat, 02s, htr and Eva. They were all green before I did whatever I did.
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Monday, February 17th, 2020 AT 3:06 PM
Tiny
GLEVI1127
  • MEMBER
  • 7 POSTS
So I think I’ve found the problem I’m just not sure I’m going to do from here. It seems that the slot for the engine control relay has a full twelve volts on two of the pins and five volts on the third and.06 on the four. I am fairly certain there should only be one pin with twelve volts going to it. Correct me if I’m wrong and any advice moving forward would be much appreciated.
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Monday, February 17th, 2020 AT 4:47 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 51,136 POSTS
The battery voltage is low. lets confirm the battery failure using this guide. Here are the fuse locations as well so you can double check them:

https://www.2carpros.com/articles/car-battery-load-test

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.
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Monday, February 17th, 2020 AT 7:04 PM
Tiny
GLEVI1127
  • MEMBER
  • 7 POSTS
I used my scanner to test the alternator and battery just before all these problems started happening. I found that the relay for the engine control is getting power across three of the four pins so I’m looking into removing the fuse box to see what I find. I’m just a little Leary about doing this since I read that disconnecting the battery could leave me with even more problems then I already have. Any advice or tips would be greatly appreciated.
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Monday, February 17th, 2020 AT 7:24 PM
Tiny
JOETECHPRO
  • MECHANIC
  • 705 POSTS
Hey GLEVI1127,

Can you please confirm you have checked the fuses first.

There is a lot of time wasted in electrical diagnosis by people not beginning with confirming that the fuses are good.

Please let us know.

You should have 12V at either side of the ECM fuse in the under hood fuse box with the ignition on.

This will confirm that the ignition relay you are testing is operating correctly.

It is fuse 42, 20amp.

Regards, Joe
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Monday, February 17th, 2020 AT 9:30 PM
Tiny
GLEVI1127
  • MEMBER
  • 7 POSTS
There is.09 volts on the fuse with the key off and I need to go purchase a battery charger or cables but there’s 11.74 with the key on. Should it not read 0 volts with the key off though? I’m going to check for a short in one of the injectors this morning once I track down some cables or a charger. Any further advice is always helpful thank you.
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Tuesday, February 18th, 2020 AT 9:16 AM
Tiny
JOETECHPRO
  • MECHANIC
  • 705 POSTS
Hey GLEVI1127,

I wouldn't worry about the 0.09V that is completely normal.

If you have 12V at both sides of that fuse with the ignition on then the relay is functioning correctly.

Can you please charge the battery and delete the fault codes?

Run the engine and recheck that codes that you have stored.

Please give us a list of the codes you have present.

Regards, Joe
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Tuesday, February 18th, 2020 AT 8:21 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 51,136 POSTS
This guide will help:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back.
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Saturday, February 22nd, 2020 AT 10:42 AM

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