DRL failure after PCS replacement

[smoknyreyz]

Anyone have a daytime running light failure after PCS replacement? Picked the truck up last Thursday after replacement and didn’t notice the DRL was out. Drove at night for the first time since repair today and realized the DRL was off. Checked service screen and see the attached errors.

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[UberNoob]

Mine was fixed with zero issues / alerts present. You should message service in the app likely they give you a fast pass or tell you to bring it back or they do a remote diag / reset something.

When I installed my lightbar per the instructions, I connected the 48v bat in the wrong order and it threw a bunch of errors like those, just did a 2 thumb reset and it went back to normal.

 

[mongo]

Anyone have a daytime running light failure after PCS replacement? Picked the truck up last Thursday after replacement and didn’t notice the DRL was out. Drove at night for the first time since repair today and realized the DRL was off. Checked service screen and see the attached errors.

None of those alerts are DRL related, what are the more recent ones?
Have tried doing a dual scroll wheel reset and Power Off?

 

[smoknyreyz]

Mine was fixed with zero issues / alerts present. You should message service in the app likely they give you a fast pass or tell you to bring it back or they do a remote diag / reset something.

When I installed my lightbar per the instructions, I connected the 48v bat in the wrong order and it threw a bunch of errors like those, just did a 2 thumb reset and it went back to normal.

Thanks. I did a two thumb reset last night and also a full power down. No luck unfortunately. I requested service last night too with a request for mobile service as I live about an hour from the service center. It’s still early but right now the app is showing for me to schedule an on site appointment at the service center with first availability July 9. I plan to call when they open today.

 

[smoknyreyz]

None of those alerts are DRL related, what are the more recent ones?
Have tried doing a dual scroll wheel reset and Power Off?

Yup. No luck with reset. Tried last night

 

[mongo]

Yup. No luck with reset. Tried last night

What alerts are at the top of the list?

 

[tinGLARE]

OP, I have a skill in grok that's dedicated to cybertruck. i gave grok info about this thread and the screenshot and they drafted a response. maybe this helps, and i hope its ok I did this....

---

Hey smoknyreyz,

I spent some time looking at the service mode screenshot you posted and cross-referenced it with similar cases. Here’s a clear breakdown of what’s showing up:



### The Important Alerts
The real issues are these two:

- **Recurring red alerts: VCLEFT_a096_HVBATTCON_MIA** (multiple times, including several on June 22 and more recent ones)
This is the main one.
- **VCLEFT** = Left Vehicle Controller (the main body/controller module on the driver’s side).
- **HVBATTCON** = High Voltage Battery Controller (the module that handles communication and control for the high voltage battery interface/contactors).
- **MIA** = Missing In Action.

It means the left vehicle controller is not receiving the expected messages from the HV battery controller. This is a communication fault that has happened repeatedly. These types of persistent MIA faults are commonly tied to power distribution or connection problems in the HV/48V system.

- **Active alert: EGGLEFTVC_a240_seatUncalTrack**
This is a seat track/position calibration fault. It’s almost certainly a side effect of the PCS replacement (modules lose their calibration data when power is interrupted). Not a driving concern, but service can recalibrate it easily.

The other logged events (TAS geofence notify, GTW already in reverse, DI accel pressed in park) are minor and not concerning.

### Why This Is Happening After the PCS Replacement
The **Power Conversion System (PCS)** is the unit that converts high voltage from the battery down to the 48V system that powers most of the truck’s electronics and manages charging. Early Cybertrucks had a number of PCS failures that produced exactly these kinds of widespread controller communication problems.

Even after the PCS was replaced, you’re still seeing the **HVBATTCON_MIA** faults. This usually points to one of the following:
- A connector not fully seated or slightly damaged during the repair
- Wiring harness issue (pinched, loose, or damaged) around the PCS or battery area
- The new PCS needing specific post-installation calibration or software procedures that weren’t completed
- A broader connection problem that existed alongside the original PCS failure

### Connection to Your DRL Issue
Your daytime running lights not working is very likely related to the same problem. The front light bar/DRLs run on the 48V system. When there’s ongoing communication instability between the vehicle controller and the HV battery controller, it can prevent proper power delivery or initialization of lighting modules. The alerts you’re seeing aren’t specific “DRL codes,” but the overall electrical condition explains why the DRLs aren’t coming on.

### Recommendations for Your Service Appointment
Since the two-thumb reset and full power down didn’t clear the recurring **HVBATTCON_MIA** faults, this isn’t going to resolve itself with another reset.

At your appointment on July 9, I’d suggest:
- Showing them the exact screenshot with the timestamps so they can see how often the VCLEFT_a096_HVBATTCON_MIA fault has occurred.
- Asking them to thoroughly inspect and reseat all connectors around the new PCS and the HV battery interface.
- Requesting they check the wiring harness in that area for any damage that may have occurred during the original repair.
- Confirming they run the proper post-replacement calibration routines for both the PCS and the left vehicle controller.

If mobile service is still showing as an option or you can call the service center to ask about getting seen sooner, it might be worth pushing for — especially since you’re an hour away.

Hope this helps give you a clearer picture going into the appointment.

---

 

[smoknyreyz]

OP, I have a skill in grok that's dedicated to cybertruck. i gave grok info about this thread and the screenshot and they drafted a response. maybe this helps, and i hope its ok I did this....

Thanks. Yea I ran it through Grok last night and got the same response. Now just trying to get mobile service out vs waiting on a July 9 appointment on site. Was just curious if anyone here had experienced the same.

 

[smoknyreyz]

What alerts are at the top of the list?

 

[smoknyreyz]

Here you go

 

[TyPope]

Looks like a list of things that popped up when they had the HVATT disconnected. Shouldn't affect anything currently. But, that's just my take.

 

[mongo]

Looks like a list of things that popped up when they had the HVATT disconnected. Shouldn't affect anything currently. But, that's just my take.

OP picked up the truck Thursday (June 18) so that's all post repair .

 

[mongo]

Weird, nothing about the DRL. It's on CAN, so I would expect some status if it failed. Maybe vehicle software or configuration is corrupted.

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