Code U0073?

TONY02

MEMBER
2012 TOYOTA COROLLA
135,000 MILES

Have the car listed above that has a U0073 code the ABS and traction control light is on and the emergency brake light flickers when driving and the speedometer goes crazy as well. Where can I start with the diagnosing?

Wednesday, June 4th, 2025 AT 3:09 PM

7 Replies

ALYSSA L

MEMBER
2 POSTS

You should start by checking the battery and ground connections-most communication issues come from low voltage or bad grounds.

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Thursday, June 5th, 2025 AT 12:23 AM

KEN L

MASTER CERTIFIED MECHANIC
52,185 POSTS

So this is probably the cluster going bad or the cluster has a bad ground, I would remove the cluster and check the wht/blk wire for ground, this guide can help you:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

U0073 - Control Module Communication Bus "A" Off

Check out the images (below). Please let us know what happens.

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Thursday, June 5th, 2025 AT 2:01 PM

TONY02

MEMBER
83 POSTS

I checked all my ground connections and cleaned them. I also checked the cluster, and I have two black and white wires and they both have ground on them with key on and with key off.

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Sunday, June 8th, 2025 AT 8:47 AM

TONY02

MEMBER
83 POSTS

I uploaded a video of what the car is doing and also the A/C stops working at the same time it happens.

Video (Click to make bigger)

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Sunday, June 8th, 2025 AT 8:48 AM

KEN L

MASTER CERTIFIED MECHANIC
52,185 POSTS

I forgot to tell you to unplug the cluster when testing did you do that? If so, I would get a rebuilt/used cluster to see if it fixes it. Also, you can send the cluster in for testing, search google for a place that can handle that kind of test.

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Sunday, June 8th, 2025 AT 11:32 AM

TONY02