Permanent trouble codes

[MauiSteve]

21 JLR
I sort of expected this.
When I installed the winch and fog lights this weekend I connected the grounds for the fog lights and the winch solenoid (not the actual winch of course) to the factory ground connector right behind the air intake on the right side of the engine house (circled in photo). When I loosened the nut to slip the ring terminals on there were some whirring and other noises. I hooked everything up and tested and all was good.
Then, when I started it, I got the Check Engine Light. My Blue Driver reports:
4 "permanent" codes
U110C Lost fuel level message
U0140 Lost communication with body control module
U0109 Lost communication with fuel pump control module
U110E Lost ambient air temp
Everything works
Blue driver says I can't clear these, they will clear when the computer is satisfied it's ok.

"Open the pod bay doors HAL
I can't do that Dave"

Stanley Kubrick got it right.

Sponsored

 

[The Fixer]

Since you didn't disconnect the main battery terminals first and those circuits are in constant communication with the BCM, it'll trip a code if one part of the system goes out. You'll probably have to put it through several drive cycles to get the codes to clear.

 

[MauiSteve]

Does disconnecting both batteries clear such codes?

 

[The Fixer]

Does disconnecting both batteries clear such codes?

It's possible that would clear the codes, but it will also reset the entire system; either way, it will need to go through a series of start/stop/drive cycles so that all the conditions are met and everything goes back to normal.

 

[Multihull]

You cannot clear a permanent code with a scanner or battery disconnect.
You can pass a CA SMOG check with a permanent code in place as long as you have these items in place:
No Check Engine Light (meaning no current codes)
Monitors Complete (Except for EVAP, that can be incomplete)
And this is the important part: Driven 200 miles and have 15 Warm Up cycles since the last time the DTC's codes were cleared. (So STOP trying to clear the codes as it only resets these counts)

Now doing this 200/15 task will not clear the Permanent code but rather the CA SMOG machine has been programmed to ignore the Permanent codes if 200 / 15 is complete.
Most Permanent codes relate directly to issues that related to pollution/emissions issues.

 

[MauiSteve]

No worries, it must be happy, no codes. Hawaii has no smog check so I don’t need to worry about that. We love our JLR.

 

[2019JLUS]

It seems like the codes you're seeing were triggered by loosening the ground connection, which momentarily disrupted communication between various control modules. Since you've already reconnected everything and everything works fine, here are a few things you can do:

### 1. **Drive Cycle**:
- As your Blue Driver mentioned, these permanent codes often clear on their own once the vehicle's computer is satisfied that the issues no longer exist. Driving your Jeep through several drive cycles (start, drive, stop, and turn off) might help the system verify everything is functioning correctly.

### 2. **Check Ground Connections**:
- Double-check the ground points where you connected the fog lights and winch solenoid. Make sure they are tight and clean. If the ground isn’t solid, it could continue to trigger communication issues with the modules.

### 3. **Battery Disconnect**:
- If the codes don’t clear after several drive cycles, you could try disconnecting the battery for 10-15 minutes to reset the ECU and clear any lingering communication errors. Just make sure to have any necessary radio or system codes ready for when the battery is reconnected.

### 4. **Module Reset**:
- If the codes persist, a more thorough reset might be required. The dealership can clear permanent codes through a deep reset of the affected modules, or sometimes using an advanced scan tool can help with this.

### 5. **Future Ground Points**:
- For future installs, consider using a dedicated ground bus or a chassis ground point, rather than the factory ground connector near sensitive electronics. This can help avoid interference with the factory wiring harnesses.

Since the codes relate to communication loss rather than hardware failure, it’s likely just a temporary issue caused by the ground disruption. If the Jeep runs fine, it should resolve itself soon.

Sponsored