Common Symptoms
- Speedometer reads incorrectly or not at all
- ABS warning light illuminated
- Cruise control inoperative or disengages unexpectedly
- Transmission shifts erratically or remains in limp mode
- Traction control or stability control warning lights on
- Check engine light illuminated
Most Likely Root Causes
- Faulty vehicle speed sensor or tone ring
- Damaged or corroded wiring between control modules
- Failed powertrain control module or body control module
- Poor ground connection at control module
- Internal control module communication fault
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Component Location
Vehicle speed sensor is typically located on the transmission output shaft or differential housing; control modules are usually under the dashboard or in the engine bay.
Manufacturer Notes
Some vehicles use multiple control modules to process and distribute vehicle speed signals, requiring verification of signal integrity at each module in the network.
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