Engine

P1501 — Vehicle Speed Sensor Signal Intermittent

Severity: medium Drive with care, to a shop

What P1501 means

The engine control module compares the vehicle speed sensor (VSS) signal with engine speed and other inputs, and it detected that the signal drops out or becomes implausible from time to time. Vehicle speed is used for idle control, fuel strategy and transmission operation. Because the fault is intermittent, the code may come and go.

Symptoms

  • Speedometer drops out or jumps
  • Surging or unstable idle
  • Harsh or delayed shifts
  • Check Engine light on
  • Cruise control not working or cutting out
  • Stalling or stumbling when braking to a stop

Possible causes

  1. Failing vehicle speed sensor on the transmission
  2. Worn or loose sensor drive gear
  3. Intermittent open or short in the wiring
  4. Corroded or loose connector terminals
  5. Metal debris contaminating the sensor
  6. Faulty PCM or instrument cluster (uncommon)

How to diagnose

  1. Read all codes and freeze frame data and note when the fault sets
  2. Watch the speed reading in live data to see if it drops out while driving
  3. Inspect the sensor connector and harness for security, corrosion and damage
  4. Wiggle the harness with the engine running and watch the signal
  5. Test sensor power, ground and signal circuits with a multimeter or scope
  6. Remove the sensor and check it for debris and the condition of its drive gear
  7. Compare vehicle speed with the ABS wheel speed data
  8. Clear the code and road test to see whether it returns

Common fixes

  • Replace the vehicle speed sensor
  • Replace a worn sensor drive gear
  • Repair the wiring harness or connector
  • Clean the sensor and terminals
  • Reflash or replace the PCM if it is proven faulty

P1501 on different brands

Mazda · manuals
The vehicle speed sensor (VSS) is out of its self-test range.
Mitsubishi
The two vehicle speed sensors on the drive wheels do not correlate.
Dodge · manuals
Over-speed condition detected: rear axle speed is greater than front axle speed.
Jeep · manuals
Over-speed condition detected: rear axle speed is greater than front axle speed.
Hyundai · manuals
The manufacturer-specific definition refers to battery temperature being too high.
Kia · manuals
The manufacturer-specific definition refers to battery temperature being too high.
MINI
The manufacturer-specific definition refers to the idle speed control valve being stuck closed.
Opel · manuals
The manufacturer-specific definition refers to a program error in the immobilizer control module.

Questions and answers

What does code P1501 mean?

It means the vehicle speed sensor signal is intermittent. The control module sees the speed reading drop out or disagree with other data.

Can I drive with P1501?

Usually yes, briefly and carefully. Idle surge and harsh shifts are possible, so have it diagnosed soon.

Why does the code come and go?

The usual causes are a poor connector contact, a damaged wire or a sensor that is starting to fail. These faults tend to show up with vibration and heat.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.