Ford P0929
77 stored in the gear shift module (GSM)
Quick answer
For applicable 2021–2022 Ford Escape and Mustang Mach-E vehicles in the US, P0929 with subcode 77 is identified as being stored in the gear shift module (GSM).
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 P0929 mean?
For applicable 2021–2022 Ford Escape and Mustang Mach-E vehicles in the US, P0929 with subcode 77 is identified as being stored in the gear shift module (GSM).
2. Technical explanation
The verified diagnostic meaning is: “77 stored in the gear shift module (GSM).” The supplied Ford/NHTSA communications document P0929:77 in connection with a powertrain malfunction (wrench) indicator and identify GSM software as a possible cause for certain vehicle populations. The supplied evidence does not establish that GSM software is the cause on every affected vehicle.
3. What system is affected?
Gear shift module (GSM).
4. How serious is this code?
Unknown. Severity is not established by the verified diagnostic record.
5. Symptoms you may notice
- A powertrain malfunction (wrench) indicator may be present, according to supplied Ford/NHTSA communications for certain vehicle populations.
- P0929:77 may be stored in the gear shift module (GSM).
6. Possible causes
- GSM software may be involved for vehicle populations covered by the supplied Ford/NHTSA communications.
- Other causes are not yet established by verified evidence.
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 diagnosis by a Ford dealer or qualified service provider.
- Provide the technician with DTC P0929:77 and note whether the powertrain malfunction (wrench) indicator is illuminated.
- Do not attempt high-voltage or module repair procedures yourself.
10. Step-by-step troubleshooting
- Confirm P0929:77 is stored in the gear shift module (GSM) using appropriate diagnostic equipment.
- A service provider should determine whether the vehicle is covered by, or matches the conditions of, the applicable Ford service communication.
- For populations identified in the supplied communications, Ford directs GSM reprogramming or Pinpoint Test D, depending on the communication and vehicle application.
11. When to contact service
Service is recommended because the diagnostic record identifies an issue stored in the GSM, and official Ford/NHTSA communications describe dealer-level diagnostic or programming actions for specified populations.
12. What the service center may check
- Retrieve and confirm P0929:77 in the GSM.
- Check vehicle model, model year, build details, and applicable Ford service information.
- Evaluate GSM software applicability where the service communication applies.
- Where directed by the applicable Ford communication, perform Pinpoint Test D.
13. Possible repair or resolution
- For a covered condition described in NHTSA Manufacturer Communication 10219068, Ford states that reprogramming the GSM corrects the condition.
- For the condition described in NHTSA Manufacturer Communication 10226757, Ford directs technicians to perform Pinpoint Test D.
- The correct resolution for a specific 2021–2022 Escape or Mustang Mach-E is not yet established by the supplied evidence.
14. Affected vehicles
- Ford Escape · 2021–2022 · US
- Ford Mustang Mach-E · 2021–2022 · US
15. Related TSBs / service bulletins
- NHTSA Manufacturer Communication 10219068, SSM 51057, published August 31, 2022: describes P0929:77 in the GSM with a powertrain malfunction (wrench) indicator for certain 2022 Escape/Bronco Sport/Maverick/Transit vehicles; the summary states GSM software may be involved and directs GSM reprogramming.
- NHTSA Manufacturer Communication 10226757, SSM 51191, published November 10, 2022: describes P0929:77 in the GSM with a powertrain malfunction (wrench) indicator for certain vehicle populations, including specified Transit vehicles; the summary directs Pinpoint Test D.
- NHTSA Manufacturer Communication 11009434, SSM 53065, published October 22, 2024: describes P0929:77 in the GSM with a powertrain malfunction (wrench) indicator for specified Transit vehicles built on or before May 17, 2022.
- The supplied summaries do not establish that these communications apply to every 2021–2022 Ford Escape or Mustang Mach-E.
16. Recall information
- No recall is established by the supplied verified evidence.
17. Official manufacturer information
Verified sources: NHTSA Manufacturer Communications 10219068 (SSM 51057), 10226757 (SSM 51191), and 11009434 (SSM 53065). Source URLs are supplied in the diagnostic record. These are manufacturer communications, not recall evidence.
- NHTSA: NHTSA Manufacturer Communication 10219068: SSM 51057 · official_tsb
- NHTSA: NHTSA Manufacturer Communication 10226757: SSM 51191 · official_tsb
- NHTSA: NHTSA Manufacturer Communication 11009434: SSM 53065 · official_tsb
19. Frequently asked questions
What does Ford code P0929:77 mean?
The verified record defines it as “77 stored in the gear shift module (GSM).”
Can P0929:77 turn on the wrench light?
Yes, supplied Ford/NHTSA communication summaries state that certain covered vehicle populations may exhibit a powertrain malfunction (wrench) indicator with P0929:77 stored in the GSM.
Is GSM software a possible cause?
For certain vehicle populations covered by supplied Ford/NHTSA communications, GSM software may be involved. Whether it is the cause on a particular vehicle is not yet established by verified evidence.
Is it safe to drive or charge with P0929:77?
Not yet established by verified evidence.