Vehicle Speed Sensor Intermittent Circuit (Honda)
What does P1502 mean?
The P1502 code means the vehicle's onboard diagnostic system has detected: Vehicle Speed Sensor Intermittent Circuit (Honda). This is a moderate severity code.
Common Symptoms
- Speedometer fluctuates or drops to zero intermittently
- Check Engine Light illuminated
- Automatic transmission may shift harshly or at wrong times
- Cruise control may not work
- Odometer may not accumulate mileage properly
Probable Causes (Ranked by Likelihood)
- Worn vehicle speed sensor Very High
- Corroded or loose speed sensor connector High
- Damaged wiring between the sensor and ECU Moderate
- Faulty speed sensor drive gear in the transmission Moderate
- ECU input circuit intermittent fault Low
Step-by-Step Diagnostic Procedure
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Monitor the VSS signal with a scan tool while driving and note any signal dropouts.
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Inspect the speed sensor connector on the transmission for corrosion or looseness.
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Wiggle the wiring harness at the sensor connection while monitoring for signal changes.
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Remove the speed sensor and inspect the drive gear for worn or missing teeth.
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Test the sensor output with an oscilloscope for consistent signal quality.
Frequently Asked Questions
Where is the speed sensor on a Honda?
On most Honda models, the vehicle speed sensor is located on the transmission housing. On newer models, the VSS signal may come from the ABS wheel speed sensors via the ABS module.
Can a bad speed sensor damage my transmission?
It will not cause direct damage, but incorrect shift timing from a faulty speed signal can increase wear on the transmission over time. Harsh shifts are harder on clutch packs and bands.
Why does the code say intermittent?
The ECU detected the speed sensor signal dropping in and out during driving. This is different from a complete sensor failure and usually points to a connection issue or a sensor that is beginning to fail.