AC Charging Current Limited by Station Signal
What does TESLA-CHARGE_a191 mean?
The TESLA-CHARGE_a191 (Tesla) EV fault code means: AC Charging Current Limited by Station Signal. This is a minor severity code.
Common Symptoms
- Charging screen shows a lower max amperage than you expected, such as 16A instead of 32A
- Estimated charge completion time is much longer than usual at this location
- Touchscreen displays a message like 'Charging speed reduced' or shows a yellow charging icon
- CHARGE_a191 appears in the service menu or via Scan My Tesla app
- Car is charging but the power delivery (kW) is noticeably lower than the station is rated for
- Charge rate fluctuates up and down while plugged in at the same station
- No fault appears at home or at a different public charger with the same cable
Probable Causes (Ranked by Likelihood)
- Station is advertising reduced available current via the J1772 pilot signal, often because it is sharing capacity across multiple stalls or circuits Very Likely
- Older 30A or 40A J1772 EVSE station is simply at its rated limit and cannot deliver more Very Likely
- Destination charger at a hotel, restaurant, or parking garage is load-managed and has throttled available amps dynamically Likely
- Station is experiencing a partial fault or its internal power management firmware is misconfigured, causing it to advertise lower current than its hardware supports Possible
- Wiring from the panel to the EVSE is undersized or has high resistance, causing the station to self-limit as a protective measure Possible
- Loose or corroded J1772 connector on the station side is causing pilot signal degradation, which the car interprets as a reduced-current advertisement Less Likely
- Onboard charger (OBC) in the car is derated due to thermal conditions or a separate OBC fault, and CHARGE_a191 is logged alongside the real limiting fault Less Likely
Step-by-Step Diagnostic Procedure
Open the Tesla touchscreen charging screen while plugged in and note the displayed max amperage. If it shows less than you expect, this confirms the car is seeing a reduced pilot signal from the station, not a car-side fault.
Check the EVSE nameplate or app (if the station has one) for its rated amperage. A 30A J1772 station legally delivers only 24A continuous (80% of rated). A 40A station delivers 32A. Compare this to what the car is showing.
Unplug and move to a different stall at the same location if available. Many destination charger installations share a single circuit breaker across multiple stalls. A different stall with no other cars on it may give you the full rate.
Try the same charge cable at a known-good Level 2 station such as a ChargePoint or Blink unit rated at 32A or higher. If the car charges at full speed there, the fault is entirely the station, not your car.
Use the Scan My Tesla app with an OBDLink MX+ or Veepeak adapter to pull active codes. If CHARGE_a191 is the only code present and no BMS or OBC codes accompany it, the car hardware is fine.
Inspect the J1772 connector on the station end. Look for burned or corroded pins, physical damage to the latch, or a loose fit in your car's charge port. A degraded connector can cause pilot signal noise that the car reads as a reduced-current command.
If you manage or own the charging equipment, contact the EVSE installer or manufacturer to verify the load-management settings. Some commercial units are deliberately set to 16A or 20A by the installer regardless of the circuit capacity.
If the issue follows your car to multiple stations that other EVs use without complaint, schedule a Tesla service appointment to inspect the onboard charger and J1772 pilot signal receiver. This is a rare scenario but indicates a car-side fault rather than a station issue.
Frequently Asked Questions
What does Tesla code CHARGE_a191 mean?
It means the charging station is telling your car to draw less current than you might expect. Tesla reads the J1772 pilot signal that every AC charging station broadcasts, and CHARGE_a191 logs when that signal indicates a reduced current limit. This is almost always a station limitation, not a car problem. Shared destination chargers, older 30A stations, and load-managed commercial chargers are the most common triggers.
Can I still drive and use the car with this code active?
Yes. The car is charging, just more slowly than ideal. You can drive normally at any time. The code does not affect driving range, performance, or safety. It is a charging status note, not a vehicle fault.
How much does it cost to fix CHARGE_a191?
Usually nothing. If the station is at fault, which is the case the vast majority of the time, the fix is to use a different charger. If the station owner needs to upgrade wiring or reprogram their EVSE, that is their expense. On the rare occasion the car's onboard charger is actually at fault, OBC repair or replacement runs $800 to $2,500 at an independent EV shop.
Will my car still charge overnight with this code?
Yes, it will charge, just at a reduced rate. Calculate whether the slower amperage is enough to reach your target charge level before you need the car. For example, at 16A on a 240V circuit you get roughly 3.5 kW, which adds about 11-12 miles of range per hour. If you have eight hours and need 80 miles of range added, that is enough. If you need more, find a higher-capacity station.