Vehicle Speed Sensor # 1 Output Circuit Short to Gnd
The vehicle speed sensor is sending a constant ground signal instead of the varying electrical pulses it should produce, like a light switch stuck in the 'off' position instead of flickering on and off. This short circuit prevents the engine computer from accurately knowing how fast the car is traveling.
The ECM monitors the VSS #1 output voltage, expecting alternating pulses that correlate to wheel speed. When the sensor shorts to ground, the voltage remains at 0V instead of oscillating between normal ranges. The ECM detects this continuous low voltage as an abnormal condition and sets the fault code.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| VSS #1 Output Voltage | 0.5–4.5V (pulsing signal) | 0V continuously (shorted to ground) |
| Signal Frequency | Varies with vehicle speed | No signal variation detected |
Code C1752 is classified as a serious fault. If your check engine light is flashing — not just steady — pull over safely and do not continue driving. A flashing CEL indicates an active misfire or critical failure that can cause catalytic converter damage within minutes or permanent engine harm within miles. Contact a certified mechanic immediately. Do not attempt roadside repairs on high-severity codes unless you are trained to do so.
Once the fault is repaired, C1752 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.