Dreaded check engine light

[wanderer]

In this continuing saga, my Jeep is now been at the dealership for 15 days out of the month and I talk to the service manager today. This is what he told me.

AP058A code should not trigger a check engine light. It should be something simple like a loose ground wire or bad battery monitoring unit. He says it’s basically downstream. Whatever that means.

He thinks the check engine light has an underlying cause he didn’t say that that threw any codes just that he thought the P058 a code should not be triggering a check engine light he’s going to continue to research it
I don’t know if this is bullshit or legit. I know a fair amount about cars and I understand some technical stuff, but this electronic stuff is beyond my comprehension.
Have any of you ever heard of anything like this? Do you have any ideas? Thanks.

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[Terrymo]

Just wanted to say thanks to you and the handful of others that seriously know what the fuck they're talking about that are willing to share their knowledge.

Yes @mwilk012 and @alphawolff in particular who despite the fact that they do this all day for a living, are still gracious enough to offer help on the forums.

 

[Jeep Wick]

In this continuing saga, my Jeep is now been at the dealership for 15 days out of the month and I talk to the service manager today. This is what he told me.

AP058A code should not trigger a check engine light. It should be something simple like a loose ground wire or bad battery monitoring unit. He says it’s basically downstream. Whatever that means.

He thinks the check engine light has an underlying cause he didn’t say that that threw any codes just that he thought the P058 a code should not be triggering a check engine light he’s going to continue to research it
I don’t know if this is bullshit or legit. I know a fair amount about cars and I understand some technical stuff, but this electronic stuff is beyond my comprehension.
Have any of you ever heard of anything like this? Do you have any ideas? Thanks.

If I were you, I would buy myself an obd scanner like obdlink MX which works with AlfaOBD and JScan. Read your own codes. Then go buy a new AGM battery and stop wasting your time at the dealer.

 

[Terrymo]

If I were you, I would buy myself an obd scanner like obdlink MX which works with AlfaOBD and JScan. Read your own codes. Then go buy a new AGM battery and stop wasting your time at the dealer.

This is great advice. JSCAN is so simple even I figured it out.

 

[wanderer]

I have a scanner And read the code cleared it came back a couple days later Jeep is still under warranty I don’t want to modify it
In any way that would give the dealer an out

 

[Heimkehr]

AP058A code should not trigger a check engine light. It should be something simple like a loose ground wire or bad battery monitoring unit.

He says it’s basically downstream. Whatever that means.

By way of example, an upstream O2 sensor is connected between the engine and the catalytic converter ("before" the converter). A downstream O2 sensor is connected to the exhaust after the converter.

As P058A means Battery Monitor Module Performance, it'd be interesting to know how the word downstream applies in that circumstance.

 

[wanderer]

If I understood you correctly, I think that’s exactly right. I think that’s why the dealer is saying that there’s an underlying issue. It’s throwing the check engine light, which may or may not be related to the P058A code.

 

[mwilk012]

Just another problem with dealerships. The person you talk to doesn’t work on cars, probably never has. Half the time, they’re just making stuff up. You’re getting information second or third hand and you’re just hoping that the tech who actually has his hands on it is in the right ballpark when it comes to an answer.

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