P0857: Traction Control Input Signal Range/Performance

What does P0857 mean?

P0857 is a diagnostic trouble code indicating "Traction Control Input Signal Range/Performance". The sensor or component is providing readings, but they fall outside the expected operating range. The part may be degraded, contaminated, or experiencing intermittent issues affecting transmission performance.

Symptoms you may notice

• Check engine light (MIL) illuminated on dashboard
• Intermittent warning lights
• Erratic gauge readings

Common causes

• Worn or contaminated transmission component
• Vacuum leak or intake air leak
• Clogged filter or restricted flow
• Intermittent electrical connection issue

What should you do?

This code sits in the stability and traction control system. Electronic stability control, traction control and the sensors feeding them may be offline, so the car will not correct a slide for you. It will feel completely normal right up until you need it, typically in the wet or in a sudden swerve. Get it diagnosed before driving in poor conditions.