The P0758 diagnostic trouble code appears in automatic transmission vehicles.
It means that there is a disparity between the actual gear set by the transmission from the gear that the powertrain control module (PCM) expects it to be.
What Does Code P0758 Mean?
Diagnostic trouble code (DTC) P0758 stands for “Shift Solenoid B Electrical”.
The purpose of the automatic transmission is to match the engine’s optimum power and torque characteristics to the driver’s desired rate of acceleration and speed by auto-selecting different gear ratios or ‘speeds’ to power the wheels.
Shift solenoid B enables the transmission to shift from 2nd gear to 3rd gear. It does this by re-directing the flow of the transmission fluid which changes the position of the shift valves in the valve body.
When the code P0758 is set in the Powertrain Computer, it means that the Powertrain Computer or PCM is not seeing the specified rpm change that occurs during a shift from 2nd gear to 3rd gear.
It’s also not seeing the correct increase in road speed from the vehicle speed sensor.
Potential Causes of a P0758 Code
Causes for this P0758 transmission code may include:
- Insufficient fluid level
- Dirty or contaminated fluid
- Dirty or clogged transmission filter
- Defective transmission valve body
- Restricted hydraulic passages
- Transmission has internal failure
- Faulty shift solenoid
- Corroded or damaged connector
- Faulty or damaged wiring
- Faulty PCM
What are the Common Symptoms of the P0758 Code?
To identify any trouble code, one should be aware of the symptoms of that particular error code.
Below are the common symptoms of error code P0758, which may help you to identify this error code:
- Check Engine Light will illuminate
- Vehicle will not shift from 2nd gear to 3rd gear properly
- Decrease in fuel economy
- In unusual cases, there are no adverse conditions noticed by the driver
- In some cases, there may be performance problems and possibly misfire-like symptoms
How to Fix P0758 Code?
- Shift Solenoid – A shift solenoid is a required part of a functioning transmission, shift solenoids job is as it sounds, shifts the gears for you. A faulty shift solenoid can prevent fluid pressure from activating the appropriate gear. As a result, the transmission may not shift gears or it may get stuck in neutral. As this code is related to shift solenoid so make sure it should work efficiently else replace it immediately.
- Shift Valves – Shift valves supply hydraulic pressure to the clutches and bands to engage each gear. The valve body of the transmission contains several shift valves. The shift valve determines when to shift from one gear to the next.
- Transmission Filter – Clogged transmission filter restricts the flow of transmission fluid to go through from it. It should be replaced immediately if found clogged so that your vehicle can continue to drive at its optimal potential.
- Transmission Valve Body – The transmission valve body is the top control area of the transmission. This valve body is responsible for directing hydraulic fluid (or transmission fluid) to various valves so the appropriate clutch can be activated. After this happens, you are able to shift the gear to whatever one you need for your particular driving situation. Repair or replace the faulty one in no time.
- Powertrain Control Module – A powertrain control module, abbreviated PCM, is an automotive component, a control unit, used on motor vehicles. It is generally a combined control unit, consisting of the engine control unit (ECU) and the transmission control unit (TCU). Though it fails rarely but if in case it happens then do the necessary replacements immediately.
How Much Does it cost to Fix a P0758 Code
To fix a P0758 code, which typically indicates a faulty shift solenoid B, you can expect to pay anywhere between $200 and $500.
Depending on your vehicle make and model, with the majority of costs falling around the $300 mark; this includes the cost of the replacement solenoid, labor to access and replace it, and potentially a transmission fluid change if required.