Vehicle Speed Sensor Circuit Failure

The vehicle speed sensor is telling the computer how fast the vehicle is going, but it's either not working or the signal isn't getting through. This happens when there's a bad connection, wiring issues, or a faulty sensor.

The computer expects a variable voltage signal from the speed sensor that changes with vehicle speed. For instance, at 30 mph, it might send a signal of around 2.5 volts. If it sees a constant voltage or no voltage at all (like 0 volts), it sets this code.

Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.

1. 1Check the vehicle speed sensor wiring for damage or visible wear at both the sensor and the ECU connections. Repair as necessary. Decision Point: Are there visible issues? If yes, fix them, retest; if no, go to the next step.
2. 2Test the voltage at the sensor connector with the ignition on (engine off). Expect a voltage change as the wheel turns. Decision Point: Is there a changing voltage signal? If yes, the sensor is likely good; if no, sensor may be faulty, replace it.
3. 3Use a multimeter to check resistance in the sensor (check specs for your specific vehicle). Typical resistance is usually around 400-1200 ohms. Decision Point: Is the resistance within expected values? If yes, check wiring continuity to the ECU; if no, replace the sensor.
4. 4Inspect the ECU for any fault codes that might indicate a larger issue such as a wiring harness problem or control module fault. Decision Point: Are there additional fault codes? If yes, address those; if no, replace ECU only as a last resort after all other diagnostics.

• Faulty vehicle speed sensor
• Damaged wiring to the sensor
• Bad connector or corroded pins
• Issues with the ECU
• Faulty wheel speed sensors if applicable

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