Vehicle Speed Sensor Intermittent (Ford)
What does P1500 mean?
The P1500 code means the vehicle's onboard diagnostic system has detected: Vehicle Speed Sensor Intermittent (Ford). This is a moderate severity code.
Common Symptoms
- Speedometer works intermittently or drops to zero
- Check Engine Light illuminated
- Transmission may not shift properly
- Cruise control does not engage
- ABS or traction control warning lights may appear
Probable Causes (Ranked by Likelihood)
- Faulty vehicle speed sensor Very High
- Damaged or corroded speed sensor connector High
- Worn or damaged speed sensor drive gear Moderate
- Intermittent wiring fault in the speed sensor circuit Moderate
- Faulty PCM input circuit Low
Step-by-Step Diagnostic Procedure
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Monitor the vehicle speed sensor signal on a scan tool while driving. Look for dropouts or erratic readings.
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Inspect the speed sensor connector for corrosion, loose fit, or damaged pins.
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Check the speed sensor mounting for a secure fit and inspect the drive gear for broken teeth.
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Wiggle the wiring harness near the sensor while monitoring the scan tool signal.
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Test the sensor output with an oscilloscope for clean, consistent square wave signals.
Frequently Asked Questions
Can a bad speed sensor cause transmission problems?
Yes. The PCM and transmission control module use the vehicle speed sensor signal to determine shift points. An intermittent signal can cause harsh shifts, delayed shifts, or failure to shift.
Where is the vehicle speed sensor?
On most Ford vehicles, the VSS is located on the transmission or transfer case. On some models, wheel speed sensors from the ABS system provide the vehicle speed signal.
Why does P1500 say intermittent?
P1500 is set when the PCM detects the speed sensor signal dropping out momentarily rather than being completely absent. This points to a loose connection, damaged wire, or failing sensor.