Volkswagen C124800
restricted function due to implausible signal, passive/sporadic Symptom 20485 Technical Service Bulletin Transaction No: 2064412/2 01-21-10 - Irrelevant Diagnostic Trouble Codes
Quick answer
For 2021–2022 Volkswagen ID.4 vehicles in the US, DTC C124800 is documented by Volkswagen as “restricted function due to implausible signal, passive/sporadic” in the brake electronics control unit (address 0003), with symptom code 20485. Volkswagen’s cited Technical Service Bulletin identifies it among irrelevant DTCs logged in various control units.
This page separates verified manufacturer/regulator evidence from supporting material. Unsupported causes, repairs or safety conclusions are not guessed.
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1. What does C124800 mean?
For 2021–2022 Volkswagen ID.4 vehicles in the US, DTC C124800 is documented by Volkswagen as “restricted function due to implausible signal, passive/sporadic” in the brake electronics control unit (address 0003), with symptom code 20485. Volkswagen’s cited Technical Service Bulletin identifies it among irrelevant DTCs logged in various control units.
2. Technical explanation
Verified evidence identifies C124800 as a passive/sporadic entry in the brake electronics control unit, diagnosis address 0003. The documented text is “restricted function due to implausible signal,” with symptom code 20485. The cited Volkswagen Technical Service Bulletin is titled “Irrelevant Diagnostic Trouble Codes (DTCs) Logged in Various Control Units,” transaction number 2064412/2, released October 17, 2022. The supplied evidence does not establish a component failure, a specific root cause, or a vehicle-operating consequence from C124800 alone.
3. What system is affected?
Brake electronics control unit, diagnosis address 0003.
4. How serious is this code?
Not yet established by verified evidence.
5. Symptoms you may notice
- C124800 may be recorded as passive/sporadic in the brake electronics control unit.
- The verified associated symptom code is 20485.
- No driver-visible symptoms are established by the supplied verified evidence.
6. Possible causes
- The verified evidence describes an implausible signal but does not establish the source of that signal or a specific root cause.
- The Volkswagen bulletin categorizes the documented entry within irrelevant DTCs logged in various control units.
7. Can I still drive the vehicle?
Not yet established by verified evidence.
8. Can I charge the vehicle?
Not yet established by verified evidence.
9. What you can safely do
- Do not assume that C124800 alone identifies a failed brake-system component.
- Have the complete diagnostic record, including DTC status and symptom codes, evaluated by a qualified Volkswagen service provider if diagnosis is needed.
- No high-voltage repair procedure is supported by the supplied evidence.
10. Step-by-step troubleshooting
- Confirm that the code is C124800 and that symptom code 20485 is present in brake electronics control unit address 0003.
- Review the complete set of stored DTCs rather than interpreting C124800 in isolation; the cited bulletin states that combinations of DTCs and symptom codes are important.
- Compare the vehicle findings with Volkswagen Technical Service Bulletin transaction 2064412/2, “Irrelevant Diagnostic Trouble Codes (DTCs) Logged in Various Control Units.”
11. When to contact service
Contact a Volkswagen dealer or qualified Volkswagen service provider for interpretation of the complete diagnostic scan. Service urgency is not established by the supplied verified evidence.
12. What the service center may check
- Check the brake electronics control unit at diagnosis address 0003 for C124800 and symptom code 20485.
- Review other stored DTCs and their symptom codes because the cited Volkswagen bulletin states that the combination of DTCs and symptom codes is important.
- Review applicability of Volkswagen Technical Service Bulletin transaction 2064412/2.
13. Possible repair or resolution
- Not yet established by verified evidence.
- The supplied evidence supports that Volkswagen published a bulletin concerning irrelevant DTCs, but it does not provide a verified repair procedure or repair outcome for C124800.
14. Affected vehicles
- Volkswagen ID.4 · 2021 · US
- Volkswagen ID.4 · 2022 · US
15. Related TSBs / service bulletins
- Volkswagen Technical Service Bulletin transaction 2064412/2, “Irrelevant Diagnostic Trouble Codes (DTCs) Logged in Various Control Units,” release date October 17, 2022. NHTSA manufacturer communication: MC-10224843-0001. URL: https://static.nhtsa.gov/odi/tsbs/2022/MC-10224843-0001.pdf
- NHTSA manufacturer communication: MC-10224845-0001. URL: https://static.nhtsa.gov/odi/tsbs/2022/MC-10224845-0001.pdf. Its supplied excerpt documents C124800 with symptom 20482, rather than symptom 20485.
16. Recall information
- Not yet established by verified evidence.
17. Official manufacturer information
Verified applicability: US-market 2021 and 2022 Volkswagen ID.4. The supplied official NHTSA-hosted Volkswagen bulletin evidence documents C124800 in brake electronics control unit address 0003 as passive/sporadic, with symptom code 20485 in transaction 2064412/2.
19. Frequently asked questions
What does Volkswagen DTC C124800 mean?
The verified Volkswagen bulletin text describes C124800 as “restricted function due to implausible signal, passive/sporadic.”
Which control unit logs C124800?
The verified evidence places C124800 in the brake electronics control unit, diagnosis address 0003.
What symptom code is associated with C124800?
The supplied excerpt for Volkswagen TSB transaction 2064412/2 associates C124800 with symptom code 20485. A separate supplied official bulletin excerpt associates the same DTC with symptom code 20482.
Does C124800 prove a brake-system part has failed?
No specific failed component is established by the supplied verified evidence.
Is C124800 safe to drive with?
Not yet established by verified evidence.