P0858 OBD-II Trouble Code: Traction Control Input Signal Low

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0858 code

P0858 is a diagnostic trouble code (DTC) for "Traction Control Input Signal Low". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$20.00
Toyota$20.00
BMW$20.00
SCHEDULE P0858 DIAGNOSTIC Get a fair and transparent estimate upfront

P0858 code definition

When the powertrain control module (PCM) detects a problem with the traction control input signal circuit, a P0858 trouble code is stored. The traction control input signal circuit delivers data to the PCM via a signal, which the PCM then uses to calculate how much the engine revolutions per minute (RPMs) are needed, engine timing, and how much fuel is needed for current vehicle traction. The P0858 trouble code only applies to vehicles that have an electronic traction control system. Some related trouble codes include P0856, P0857, P0859, and P0860.

What the P0858 code means

When the PCM, or a related module, doesn't receive input from the traction control module, a P0858 trouble code is stored and the check engine light illuminates. In some models, the traction control light might also illuminate and the transmission will be placed in Limp-in mode.

What causes the P0858 code?

A defective traction control ON/OFF switch is the most likely culprit behind the storage of a P0858 trouble code. Other causes can include damaged wiring or electrical connectors, corrosion in the sensor connector, and liquids spilled into the traction control switch.

What are the symptoms of the P0858 code?

Symptoms of a P0858 trouble code include the traction control system failing to operate, which is most obvious in slippery driving conditions. In addition to the warning lights, drivers can encounter problems when shifting gears and an increase in overall fuel usage while driving.

How does a mechanic diagnose the P0858 code?

To properly diagnose a P0858 trouble code, a mechanic needs an advanced scanner, digital volt/ohmmeter, a specialized scanner for testing the Controller Area Network (CAN) Bus harness, and a CAN Bus system wiring diagram. In addition, the mechanic should perform the following when diagnosing:

  • Inspect the wiring, connectors, and components. In particular, look for faulty, corroded, or damaged items during inspection.
  • Download any stored trouble codes or freeze frame data.
  • Install a memory-saving device and test the pins of the CAN Bus harness for wiring for fault using a specialized CAN Bus scanner. The mechanic should keep in mind that this process is time consuming and cost prohibitive.
  • Using a digital volt/ohmmeter, check the CAN Bus circuits, control modules, connectors, and fuses for fault.
  • When checking these components, connectors, and wiring, make sure to test for reference voltage and continuity with the battery ground.
  • Using the volt/ohmmeter, check the continuity and ground at the traction control ON/OFF switch.
  • Clear and retest the system to see if the problem returns.

Common mistakes when diagnosing the P0858 code

Mechanics most commonly cite the traction control module as being at fault, when in fact the problem lies with a faulty switch, circuit, or connector. Subsequent replacement of the traction control module does not fix the problem causing the P0858 trouble code and the code returns.

How serious is the P0858 code?

While a P0858 trouble code usually doesn't affect the operation of a vehicle with the code, it can lead to issues with gaining proper traction in slippery conditions. In addition, transmission issues in the form of shifting problems are commonly experienced with this code, as well as a decrease in the overall fuel efficiency of the vehicle.

What repairs can fix the P0858 code?

Fixing a P0858 trouble code requires the mechanic to complete the following repairs:

Need help with a P0858 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

trouble codes
P0858
OBD-II

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0858 code.

SCHEDULE P0858 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.8/5

Number of Reviews

5,606

Rating Summary
5,180
205
50
34
137
5,180
205
50
34
137

James

40 years of experience
34 reviews
James
40 years of experience
Ford F-150 - Check Engine Light is on - Chagrin Falls, Ohio
Jim was great! Arrived on time, quickly diagnosed the problem and recommended further work. Very helpful, I’ll use Jim again and recommend to family and friends.

Roberto

11 years of experience
137 reviews
Roberto
11 years of experience
Nissan Titan - Check Engine Light is on - Spring, Texas
Roberto was very thorough with his explanation of repairs needed. I will contact your mechanic for future repairs.

Matthew

32 years of experience
839 reviews
Matthew
32 years of experience
Kia Optima - Check Engine Light is on - Yorktown, Virginia
Matthew Lerman was God Sent, and thank God for Your Mechanic,, you have my Vote Looking , Looking forward for more Business. Very Honest Guy

Robert

20 years of experience
38 reviews
Robert
20 years of experience
Honda Accord - Check Engine Light is on - Brentwood, California
He came earlier than on time and got the job done faster than I seen anyone else have . Solid honest hard working dude.


More related articles

P0348 OBD-II Trouble Code: Camshaft Position Sensor A Circuit High Input (Bank 2)
Trouble code P0348 means the voltage reading from the camshaft position sensor circuit for camshaft sensor A in engine bank 2 is too high.
P2324 OBD-II Trouble Code: Ignition Coil I Primary Control Circuit Low
P2324 P2324 code definition Ignition Coil I Primary Control Circuit Low What the P2324 code means P2324 is an OBD-II generic code for the Ignition Coil I Primary Control Circuit Low to the Engine Control Module (ECM). This means the...
P2765 OBD-II Trouble Code: Input/Turbine Speed Sensor B Circuit
P2765 means the system is receiving a bad or no signal from the input/turbine speed sensor B due to faulty sensors or solenoids or electrical issues.

Related questions

AT light and Check engine light on stuck in third gear.

A logical place to start is with a Check Engine Light inspection to see what codes might be set. Usually with something of this nature, codes will be present, and there will be a flow chart that should be used...

Car revs high

Air leaks into the intake system (a loose hose, or the EVAP valve as you have already experienced). If there are no codes, even transient codes which may not set the Check Engine Light, the problem could be a loose...

Tranny erratic shift if the problem is in the tcm would it throw a faulty tcm code ?or not all the times this happens.

Hello and thank you for contacting Your Mechanic. The code P0760 means that the shift solenoid "C" is operating irregularity. The code P0870 means that the transmission fluid pressure is not determined at its specified pressure. Check the harness to...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com