Chevrolet P1A50
• There are no additional DTCs stored in the HPCM
Quick answer
For a 2016–2017 Chevrolet Volt (US), P1A50 is documented in GM bulletin 16-NA-400 in connection with a loss-of-propulsion diagnostic process. The supplied evidence does not establish a standalone plain-language fault definition beyond the listed condition: “There are no additional DTCs stored in the HPCM.”
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1. What does P1A50 mean?
For a 2016–2017 Chevrolet Volt (US), P1A50 is documented in GM bulletin 16-NA-400 in connection with a loss-of-propulsion diagnostic process. The supplied evidence does not establish a standalone plain-language fault definition beyond the listed condition: “There are no additional DTCs stored in the HPCM.”
2. Technical explanation
The verified source is NHTSA-posted GM manufacturer communication 16-NA-400, published December 8, 2016. It instructs technicians to review Hybrid Powertrain Control Module (HPCM) freeze-frame information when P1A50 or P1A53 is involved. One specified freeze-frame condition is that no additional DTCs are stored in the HPCM. The bulletin directs reprogramming the Drive Motor Power Inverter Module to the latest available calibrations. If the customer has experienced more than one occurrence, or if the Power Inverter Module already has the latest calibration, the bulletin directs normal SI diagnostics for P1A50 or P1A53; it states that Power Inverter Module replacement may be needed.
3. What system is affected?
Hybrid Powertrain Control Module (HPCM) freeze-frame diagnostic information and the Drive Motor Power Inverter Module are identified by the verified bulletin.
4. How serious is this code?
Unknown. The verified bulletin states that affected vehicles may have loss of propulsion in the related diagnostic scenario, but the supplied evidence does not establish severity for every instance of P1A50.
5. Symptoms you may notice
- Loss of propulsion may occur in the bulletin’s related diagnostic scenario.
6. Possible causes
- Not yet established by verified evidence. The bulletin identifies a calibration update path and states that Power Inverter Module replacement may be needed after normal SI diagnostics in certain repeat or already-updated cases.
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
- Arrange diagnostic evaluation by a qualified Chevrolet/GM service facility.
- Do not attempt high-voltage system or Power Inverter Module repair yourself.
10. Step-by-step troubleshooting
- A technician should review HPCM freeze-frame information as described in GM bulletin 16-NA-400.
- The bulletin specifies checking whether there are no additional DTCs stored in the HPCM as part of its listed freeze-frame criteria.
- The bulletin directs reprogramming the Drive Motor Power Inverter Module to the latest available calibrations.
- For more than one occurrence, or when the Power Inverter Module is already at the latest calibration, the bulletin directs normal SI diagnostics for P1A50 or P1A53.
11. When to contact service
Service evaluation is appropriate because the verified GM bulletin involves Drive Motor Power Inverter Module programming and may lead to further SI diagnostics or possible module replacement.
12. What the service center may check
- Review HPCM freeze-frame information.
- Confirm whether no additional DTCs are stored in the HPCM, as specified in the bulletin’s listed criteria.
- Check and apply the latest available Drive Motor Power Inverter Module calibrations.
- If repeat occurrence is reported or the module is already updated, perform normal SI diagnostics for P1A50 or P1A53.
13. Possible repair or resolution
- Reprogram the Drive Motor Power Inverter Module to the latest calibrations available.
- Following normal SI diagnostics in repeat or already-updated cases, Power Inverter Module replacement may be needed.
14. Affected vehicles
- Chevrolet Volt · 2016–2017 · US
15. Related TSBs / service bulletins
- GM bulletin 16-NA-400, published via NHTSA as Manufacturer Communication PDF 10111768 on December 8, 2016. It applies in the supplied data to 2016–2017 Chevrolet Volt vehicles in the US.
16. Recall information
- Not yet established by verified evidence.
17. Official manufacturer information
NHTSA-hosted GM manufacturer communication 16-NA-400: https://static.nhtsa.gov/odi/tsbs/2016/MC-10111768-9999.pdf
19. Frequently asked questions
What does P1A50 mean on a 2016–2017 Chevrolet Volt?
The supplied verified record lists: “There are no additional DTCs stored in the HPCM.” GM bulletin 16-NA-400 uses that statement as a specified HPCM freeze-frame condition in its diagnostic process.
Can P1A50 be associated with loss of propulsion?
GM bulletin 16-NA-400 states that vehicles may have loss of propulsion in the related diagnostic scenario. The supplied evidence does not establish that every P1A50 event causes loss of propulsion.
What repair does GM bulletin 16-NA-400 direct?
The bulletin directs reprogramming the Drive Motor Power Inverter Module to the latest available calibrations. For repeat occurrences or an already-updated module, it directs normal SI diagnostics and notes that Power Inverter Module replacement may be needed.