P0858
Traction Control Input Signal Low
Transmission / traction control input
Generic OBD-II
Low
What it means
P0858 means the traction control input signal seen by the powertrain computer is too low — usually a short to ground or wiring fault in that circuit. The engine and transmission keep working normally, but the traction control system may switch off or behave erratically, so grip management in slippery conditions can't be relied on until the circuit is repaired.
Low
Can I keep driving? The car starts and drives normally; the traction control link may not work as intended, so drive with extra care in low-grip conditions until it's fixed.
Common symptoms
What you'll notice
- Check-engine light on
- Traction control warning light on or system disabled
- Traction control may not activate on slippery surfaces
- Erratic traction control operation
Common causes
Most likely first
- Wiring or connector fault pulling the traction control input signal low (short to ground)Likely
- Loose or corroded connectors in the circuitCommon
- Faulty traction control / ABS moduleCommon
- Faulty traction control switch or sensor feeding the signalLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and scan the ABS/traction control module for related codes.
- Inspect the input-signal wiring and connectors for shorts to ground or corrosion.
- Measure the input signal voltage and compare it to specification.
- Repair the wiring or connectors; replace the ABS/traction control module if it is the source.
- Clear the code and re-test, confirming traction control operation.
FAQ
Quick answers
Is it safe to drive with P0858?+
Yes — the engine and transmission work normally. The concern is that traction control may be disabled, so take extra care in rain, snow, or on loose surfaces.
Can I just clear P0858?+
You can, but it returns until the low-signal wiring or module fault is repaired.
Related codes
Often seen with P0858
Read & clear P0858 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX