Vehicle Speed Sensor Failure
Indicates a problem with the vehicle speed sensor or circuit.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The vehicle uses a speed sensor to figure out how fast it's going. If this sensor sends bad signals or stops working, the computer can't tell the speed, which can cause shifting problems and affect other systems like ABS.
What the computer is actually seeing
The engine control module (ECM) expects a steady voltage signal from the speed sensor, typically around 0.5V to 5V depending on the speed. If the signal drops to below 0.2V or goes open, it sets SPN 220.
What a healthy reading looks like
Normal speed signal should vary from 0.5V at 0 MPH to nearly 5V at higher speeds, updating every few milliseconds.
Guided diagnostic — the DiagCoach way
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.
- 1Check wiring and connectors for damage or corrosion. Repair any issues found. Decision point: If repaired, clear codes and test drive. If not, proceed.
- 2Measure the voltage at the speed sensor connector while the vehicle is stationary and then while driving. Expected values: 0.5V to 5V. Decision point: If out of range, replace the speed sensor. If within range, proceed.
- 3Inspect the ECM for any updates or faults. Verify connections. Decision point: If the ECM shows a fault, consider reprogramming or replacement.
Common causes
- Failed speed sensor
- Wiring issues in the circuit
- Corroded or loose electrical connectors
- Faulty ECM
- Mechanical failure in transmission components
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's drivable but shifting may be rough, and other systems might not work properly. Fix soon.
Will this code come back after clearing?
If the issue isn't resolved, it will likely return after clearing.
Why is it paired with transmission issues?
The speed sensor is critical for transmission performance; a faulty signal affects gear changes.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →