Chevrolet U1538
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Quick answer
For applicable US Chevrolet Bolt EV model years 2017–2018, verified GM bulletin 16-NA-407 identifies U1538 as an associated BCM fault to consider when a CCM or HPCM U0422 code is current/active. The supplied evidence does not establish the definition of U1538 itself, its symptoms, driving or charging safety, or a specific repair.
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 U1538 mean?
For applicable US Chevrolet Bolt EV model years 2017–2018, verified GM bulletin 16-NA-407 identifies U1538 as an associated BCM fault to consider when a CCM or HPCM U0422 code is current/active. The supplied evidence does not establish the definition of U1538 itself, its symptoms, driving or charging safety, or a specific repair.
2. Technical explanation
The supplied official GM bulletin evidence explains that CCM/ICCM and, in a later revision, HPCM U0422 may set after one second when door-ajar VDA or door-open VDA is unavailable. The bulletin says to ignore the relevant U0422 code with no service necessary unless it is current/active or accompanied by associated BCM faults U1534 or U1538. This establishes U1538 as a BCM fault relevant to that U0422 evaluation path; it does not establish U1538’s exact fault definition or root cause.
3. What system is affected?
Body Control Module (BCM) is identified in the bulletin as the module associated with U1538. The bulletin also references CCM/ICCM, HPCM, door-ajar VDA, and door-open VDA in connection with U0422 evaluation.
4. How serious is this code?
Not yet established by verified evidence.
5. Symptoms you may notice
- Not yet established by verified evidence.
6. Possible causes
- The verified bulletin does not state a specific cause for U1538.
- In the related U0422 context, the bulletin states that door-ajar VDA or door-open VDA being unavailable can cause U0422 after one second. It does not establish that this is the cause of U1538.
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
- Record whether U1538 is current/active and capture all accompanying diagnostic codes.
- Have a qualified Chevrolet/GM service technician evaluate the vehicle using applicable service information.
- Do not treat the bulletin’s no-service instruction for U0422 as a no-service instruction for U1538; the bulletin specifically identifies U1538 as an associated BCM fault that changes the U0422 evaluation.
10. Step-by-step troubleshooting
- For a related CCM/ICCM or HPCM U0422 code, GM bulletin 16-NA-407 says it may be ignored with no service necessary only when it is not current/active and is not accompanied by associated BCM faults U1534 or U1538.
- If U1538 accompanies U0422, the supplied evidence supports further professional diagnostic evaluation. Detailed U1538 diagnostic steps are not established by the supplied verified evidence.
11. When to contact service
Contact a Chevrolet/GM dealer or qualified service technician, particularly if U1538 is current/active or is present with U0422.
12. What the service center may check
- Confirm whether U1538 is present and whether it is current/active.
- Check whether U0422 is also present in CCM/ICCM or HPCM, as applicable.
- Check for associated BCM fault U1534, which is also named in GM bulletin 16-NA-407.
- Use GM service information for any diagnostic steps beyond the bulletin’s U0422 guidance; those steps are not included in the supplied evidence.
13. Possible repair or resolution
- No specific repair or resolution for U1538 is established by the supplied verified evidence.
- For the related U0422 condition only, GM bulletin 16-NA-407 states no service is necessary when U0422 is not current/active and is not accompanied by U1534 or U1538.
14. Affected vehicles
- Chevrolet Bolt EV · 2017–2018 · US
- Chevrolet Bolt EV · 2017 · US
15. Related TSBs / service bulletins
- GM bulletin 16-NA-407, published through NHTSA manufacturer communications including MC-10111775 (December 15, 2016), MC-10134574 (October 4, 2017), and MC-10134573 (October 19, 2017). It applies in the supplied applicability data to US Chevrolet Bolt EV model years 2017–2018. The October 19, 2017 version adds HPCM information.
16. Recall information
- No recall information was supplied or established by verified evidence.
17. Official manufacturer information
Official source: NHTSA-hosted GM manufacturer communication 16-NA-407: https://static.nhtsa.gov/odi/tsbs/2017/MC-10134573-9999.pdf
19. Frequently asked questions
What does U1538 mean on a Chevrolet Bolt EV?
The supplied verified evidence does not provide an exact definition for U1538. It identifies U1538 as an associated BCM fault in GM bulletin 16-NA-407.
Does GM say to ignore U1538?
No. The bulletin says to ignore the related CCM/ICCM or HPCM U0422 code only when it is not current/active and is not accompanied by U1534 or U1538.
Is U1538 applicable to the 2017–2018 Chevrolet Bolt EV?
The supplied applicability data identifies US Chevrolet Bolt EV model years 2017–2018.
Can I drive or charge with U1538?
Not yet established by verified evidence.