Cadillac U1862
up devices causing no power in 4WD low range. • Erratic electric power steering boost potentially associated with codes U21
Quick answer
U1862 is listed in Cadillac-related official manufacturer communications among numerous communication DTCs. Those communications describe possible SES/MIL/CEL illumination, and also reference no power in 4WD low range for diesel power-up devices and erratic electric power-steering boost potentially associated with U21 codes. A vehicle-specific diagnosis is not established by the supplied evidence.
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 U1862 mean?
U1862 is listed in Cadillac-related official manufacturer communications among numerous communication DTCs. Those communications describe possible SES/MIL/CEL illumination, and also reference no power in 4WD low range for diesel power-up devices and erratic electric power-steering boost potentially associated with U21 codes. A vehicle-specific diagnosis is not established by the supplied evidence.
2. Technical explanation
Verified evidence from two NHTSA-hosted manufacturer communications (Bulletins 13-08-116-001J and 13-08-116-001K) lists U1862 with communication codes including U0100, U0101, and U186B. The supplied bulletin summaries do not provide a U1862 circuit definition, diagnostic procedure, root cause, or repair procedure. Therefore, the exact meaning and fault path of U1862 for an individual vehicle are not yet established by verified evidence.
3. What system is affected?
Communication systems are implicated by the verified bulletin summaries. The summaries also reference 4WD low-range power and electric power-steering boost, but do not establish that either condition is caused by U1862 alone.
4. How serious is this code?
Not yet established by verified evidence.
5. Symptoms you may notice
- SES, MIL, or CEL illumination may occur with numerous communication DTCs including U1862, according to the verified bulletin summaries.
- No power in 4WD low range is referenced for diesel power-up devices in the verified bulletin summaries.
- Erratic electric power-steering boost is referenced as potentially associated with U21 codes in the verified bulletin summaries.
6. Possible causes
- Not yet established by verified evidence. The supplied sources identify U1862 among numerous communication codes but do not state a specific root cause for U1862.
7. Can I still drive the vehicle?
Not yet established by verified evidence. If steering assistance is erratic or reduced, arrange professional assessment rather than relying on this page to determine drivability.
8. Can I charge the vehicle?
Not yet established by verified evidence.
9. What you can safely do
- Record all warning messages and all stored diagnostic trouble codes before codes are cleared.
- Seek qualified Cadillac/GM service diagnosis, particularly if a steering-assist concern, warning lamp, or multiple communication codes are present.
- Do not attempt high-voltage component repair based on the supplied evidence.
10. Step-by-step troubleshooting
- Have a qualified technician retrieve and evaluate all stored communication DTCs. The verified bulletins describe U1862 as occurring among numerous communication codes.
- Not yet established by verified evidence: a vehicle-owner diagnostic sequence, connector test, module test, or component-level test for U1862.
11. When to contact service
Contact a qualified Cadillac/GM service provider for diagnosis. Prompt assessment is appropriate if steering boost is erratic, reduced, or accompanied by warning messages.
12. What the service center may check
- Retrieve all stored DTCs, including accompanying communication codes; U0100, U0101, and U186B are examples named alongside U1862 in the verified bulletin summaries.
- Review applicable manufacturer information using the vehicle VIN and complete vehicle configuration.
- Not yet established by verified evidence: the specific inspection, calibration, wiring check, module test, or repair required for U1862.
13. Possible repair or resolution
- Not yet established by verified evidence. The supplied bulletin summaries do not provide a verified repair resolution for U1862.
14. Affected vehicles
- Cadillac CELESTIQ · 2014–2026 · US
- Cadillac CT6 · 2014–2024 · US
- Cadillac CT6 · 2014–2026 · US
- Cadillac ELR · 2014–2026 · US
- Cadillac ELR · 2014–2024 · US
- Cadillac LYRIQ · 2014–2024 · US
- Cadillac LYRIQ · 2014–2026 · US
- Cadillac OPTIQ · 2014–2026 · US
- Cadillac VISTIQ · 2014–2026 · US
15. Related TSBs / service bulletins
- NHTSA Manufacturer Communication 11017244, Bulletin 13-08-116-001K, published March 31, 2025: lists U1862 among numerous communication DTCs and references the described warning-lamp, 4WD low-range, and steering-boost concerns. https://static.nhtsa.gov/odi/tsbs/2025/MC-11017244-0001.pdf
- NHTSA Manufacturer Communication 11000162, Bulletin 13-08-116-001J, published April 30, 2024: lists U1862 among numerous communication DTCs and references the described concerns. https://static.nhtsa.gov/odi/tsbs/2024/MC-11000162-0001.pdf
16. Recall information
- Not yet established by verified evidence.
17. Official manufacturer information
Verified official sources: NHTSA-hosted manufacturer communications 13-08-116-001J and 13-08-116-001K. Applicability supplied for Cadillac in the US includes CELESTIQ (2014–2026), CT6 (2014–2026), ELR (2014–2026), LYRIQ (2014–2026), OPTIQ (2014–2026), and VISTIQ (2014–2026). These broad supplied ranges are applicability records, not confirmation that every listed vehicle is covered by either bulletin; VIN-specific applicability is not established by the supplied evidence.
19. Frequently asked questions
What does U1862 mean?
The supplied verified evidence lists U1862 among numerous communication DTCs. A precise circuit-level definition is not provided in the supplied bulletin summaries.
Can U1862 affect steering?
The verified bulletin summaries reference erratic electric power-steering boost as potentially associated with U21 codes. They do not establish that U1862 alone causes a steering concern.
Is there a verified fix for U1862?
Not yet established by verified evidence. The supplied sources do not include a specific repair procedure or repair outcome for U1862.
Is U1862 covered by a recall?
Not yet established by verified evidence.