Error Code P0857 is defined as Traction Control Input Signal Range/Performance. It is a generic trouble code, meaning it applies to all vehicles with the OBD-II system, especially those made from 1996 up to the present. This code only applies to vehicles equipped with an electronic traction control system. Specifications on the definition, troubleshooting, and repairs vary from one make, model, and powertrain configuration.
This code refers to a malfunction in the traction control input signal circuit. The powertrain control module (PCM) is often registered but can also be detected by other control modules related to the traction circuit.
The job of the traction control input signal circuit is that it relays information to system-related control modules. This promotes cooperation between engine performance and traction control. This problem occurs when one of the control modules has failed to receive a message from the traction control input signal circuit.
As with other error codes, the Check Engine Light is activated with this code. Other common symptoms include:
- Malfunctioned or inoperable traction control system (loss of grip, slippery on icy conditions)
- Increase in fuel consumption
- Difficulty shifting or may not shift at all
The most common cause of this code is a faulty On/Off traction control system switch. This could result from liquid contact damage with the module or one of the other related components. Other common causes include:
- Faulty, loose, or damaged connectors, disconnected wires, and other electrical components
- Corrosion in the traction control sensor connector
How to Check
The code must be identified via the OBD2 code reader connected to the vehicle’s computer.
Next, the traction control switches must be checked first, as this is the most common cause of the trouble code.
If you suspect the problem is in the traction-related control modules, you may need a special scanned such as Autohex. This scanner will save you time from inspecting all of the related control modules.
Next, inspect all the wirings and connectors related to the traction control circuit. Look for signs of corrosion, damages, and disconnected wires.
Also, make sure you check all other related components to the traction circuit.
How to Fix
If the problem is caused by a damaged or faulty traction control switch, it must be replaced. Other common repairs include:
- Repair or replacement of corroded, damaged, or faulty wiring and connections
- For repaired control modules, the module in question must be attached with a memory saver to save time and money from expensive reprogramming
Voltage readings must always be compared with the specifications set by the manufacturer. Also, the vehicle must be taken to a test drive following a thorough diagnosis and repairs.
The severity of this error code depends on its symptoms. In mild cases, the drivability of the vehicle will be affected. For more severe problems, the vehicle’s inability to shift gears will render it inoperable. Either way, this code must be addressed as soon as possible, as it poses safety problems.