U0073 , U0121 and U0155 on a 2008 Mazdaspeed 3

Hey guys. New to this forum, coming from MSF. My car threw these codes this morning and I’ve tried to do some research but can’t seem to find a definitive answer or solution to fix it.

Codes: U0073 , U0121 and U0155.

All I know is what the access port was saying is that it is comm issues with several things.

Is this something I need to take to the dealership? It’s a 2008 Mazdaspeed 3

 

Looks like an ABS issue communicating with the instrument cluster or something. pull the wheels off and check the ABS sensors to see if they are connected.

 

Probably a grounding issue. Make sure you don't have any funny business going on with your cables.

 

What cables would you advise me to check? Aside from the obvious answer “all of them” are there any specific cables to take a look at?

 

Thank you sir. Will do that tomorrow after work. Would that cause the cluster to bug out like that thought? The tachometer and speedo both went zero and the lights went on/off like a bad Christmas tree.

 

Check fuses and connections first. Keep it simple.

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Yeah. Start with the main grounds. Battery, alternator, block..? Block. It could be as easy as something wiggled loose. Also as @Raider said, check fuses as well.

 

Well, figured I would post an update. It’s been about a month since the post and he trouble codes. Checked most grounds (won’t say all because I am sure I missed some) that I could find. All are secure and tightened down, although one near the battery was slightly loose. Maybe that was the culprit? Checked my harnesses and connections as recommended. Fuses all looked good. Went ahead (against my gut feelings) and cleared the codes. Have yet to see the codes resurface. All logs show good data from voltage, AFR, boost and the gauges are acting normal. Been on a few trips over the holiday weekend and nothing. Wondering if it was just a fluke thing that happened. I appreciate your guys tips and advice.


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Glad to see the codes didn't come back.

 

If the problem persists, Check the connectors on the back of the Instrument cluster, those codes are for communication errors to the cluster, which could unfortunately be the cluster itself shitting the bed.