Servo Motor Potentiometer Foot Circuit Short To Ground
The accelerator pedal position sensor has a short circuit to ground, like a broken wire touching metal. The ECU can't properly read your pedal input and won't know how much throttle you're requesting.
The ECU monitors the potentiometer voltage output from the accelerator pedal servo motor, expecting a signal that rises as you press the pedal. When the circuit shorts to ground, voltage drops to 0V, and the ECU detects this abnormal condition as a fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Potentiometer Voltage | 0.5V to 4.5V (varies with pedal position) | Below 0.2V or stuck at 0V |
| Circuit Resistance | 5kΩ to 100kΩ (variable) | Less than 1kΩ (short to ground detected) |
Code B1279 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.
Once the fault is repaired, B1279 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.