OBD-II code · manufacturer-specific
P1778
AG4 Transmission Torque Modulation Fault
- System
- P1 — Powertrain (manufacturer-specific)
- Severity
- Moderate (3/5)
- Can I keep driving?
- Drive with caution
What does P1778 mean?
P1778 is defined as “AG4 Transmission Torque Modulation Fault”.
Drive gently and only as far as you need to; have it checked as soon as possible.
Manufacturer-specific meanings
The same code can mean something different on some makes.
- Volkswagen: Solenoid EV7 Electrical Malfunction
- Citroen, Diğer, Peugeot: Transmission Reverse I/P Circuit Malfunction
- Jaguar: Transmission Reverse IP Circuit
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This page is general information; an exact diagnosis needs measurements and a technician’s check.