P0758 Shift solenoid valve B, electrical

P0758 – OBD-II Trouble Code Technical Description

Shift solenoid valve B

What does the fault code mean P0758?

This is a transmission diagnostic trouble code (DTC) that applies to OBD-II vehicles with an automatic transmission. It includes vehicles from various brands such as Chrysler, Ford, Dodge, Hyundai, Kia, Ram, Lexus, Toyota, Mazda, Honda, VW and others. The main message is that the exact repair steps may vary depending on the make, model, and year of the vehicle.

Most automatic transmissions are equipped with multiple solenoids, including solenoids A, B, and C. Solenoid “B” related trouble codes include P0755, P0756, P0757, P0758, and P0759. These are related to specific faults that alert the PCM and may illuminate the Check Engine Light. These codes are also related to the A, B, or C solenoid circuits. If your vehicle has an Overdrive light or other transmission control lights, these may also come on.

The purpose of the shift solenoid circuit is to allow the PCM to control the shift solenoids to control the movement of fluid between the various hydraulic circuits and change the transmission ratio. This process maximizes engine performance at minimum rpm. An automatic transmission uses bands and clutches to change gears, and this is achieved by controlling the fluid pressure. Transmission solenoids operate valves in the valve body, allowing transmission fluid to flow to the clutches and bands, allowing for smooth gear changes while the engine accelerates.

Code P0758 indicates a problem with solenoid B, which controls the shift from 2nd to 3rd gear. If this code appears, it means the PCM is not detecting the correct increase in speed after shifting from 2nd to 3rd gear.

The shift solenoid circuit allows the PCM to monitor changes in gear ratios. If the PCM detects a problem in this circuit, related DTCs may appear depending on the vehicle make, transmission type, and number of gears. Code P0758 is specifically related to an electrical problem in the shift solenoid B circuit.

Possible reasons

Causes of a P0758 code include:

1. Damage to solenoid B.
2. Loose or shorted wiring or connector.
3. Defective transmission valve body.
4. Low transmission fluid level.

What are the symptoms of a fault code? P0758?

Symptoms of a P0758 code include: difficulty shifting from second to third gear, poor fuel economy, transmission slipping or overheating, transmission stuck in gear, low gear, and check engine light illuminated.

How to diagnose a fault code P0758?

An OBD-II scanner is used to quickly check the codes that the PCM records. A qualified mechanic records data related to the underlying problems that caused the code. The code is then cleared before a short test drive of the vehicle to detect symptoms. During the test drive, the vehicle is accelerated from 15 to 35 mph to determine if the P0758 code recurs and to ensure that the problem is with the shift solenoid B.

The mechanic checks the transmission fluid level and cleanliness, as well as the wiring for damage and corrosion. It is important to inspect the connectors for reliable contact and condition of the contacts.

Depending on the specific configuration, a transmission link integrity check may be required. Identifying problems specific to certain car brands requires advanced equipment for more accurate diagnosis.

Before you begin troubleshooting, it is recommended that you review the vehicle-specific Technical Service Bulletins (TSBs) for your vehicle's year, model, and transmission type. This can save time and point you in the right direction. It's also a good idea to check the transmission history, including filter and fluid changes if available.

Next, the transmission fluid level and wiring condition are checked for visible damage such as scratches, abrasions or exposed wires.

To perform additional steps, you need to use advanced equipment, such as a digital multimeter, and specific technical data for your specific vehicle make and model. Voltage requirements will vary by year and model, so refer to the specifications for your vehicle. Continuity tests should always be performed with the circuit power off and recorded using a 0 ohm resistor unless otherwise specified. Resistance or an open circuit may indicate problems that require repair or replacement of the wiring.

Diagnostic errors

Errors may occur while diagnosing the P0758 code. Some of them include:

1. Skip Pre-Check: A preliminary inspection should be carried out, including inspecting the wiring and connectors, as well as checking the level and condition of the transmission fluid. Skipping this step may result in an incorrect diagnosis.
2. Insufficient check of connectors and wires: Incorrect connections, corrosion or damaged wires can cause diagnostic errors. A mechanic should carefully check the condition of the connectors and wires.
3. Insufficient diagnosis of solenoid B: The cause of the P0758 code may not only be a faulty solenoid B, but also other problems such as corroded or damaged wiring, a faulty transmission valve body, etc. The mechanic should make sure that the diagnosis includes all possible causes.
4. Incorrect interpretation of scanner data: The mechanic must correctly interpret the data received from the OBD-II scanner. Misunderstanding of data can lead to misdiagnosis.
5. Insufficient check of the level and condition of the transmission fluid: Low fluid levels, dirty or worn transmission fluid can cause problems with solenoid B. A mechanic should carefully check the condition of the transmission fluid.
6. Unaccounted for updates or TSB: It is important to note that there are technical service bulletins (TSBs) for specific makes and models of vehicles. Unannounced updates or recommendations may be missed, which may lead to misdiagnosis.
7. Missed troubleshooting steps: Troubleshooting procedures must be followed to ensure that all problems have been resolved.
8. Insufficient engine control system (PCM) check: In some cases, faults or updates to the engine management system can cause a P0758 to be misdiagnosed. The mechanic should pay attention to PCM updates.

To accurately diagnose and resolve the P0758 code, it is important to follow the correct sequence of steps and pay attention to all aspects of the diagnosis.

How serious is the fault code? P0758?

Code P0758 indicates problems with the shift solenoid B in the automatic transmission. This error can have varying degrees of severity depending on several factors:

1. Symptoms and behavior of the car: If your vehicle begins to exhibit serious symptoms such as difficult shifting, transmission slipping, transmission overheating, or going into limp mode, then code P0758 should be taken seriously.
2. Diagnostic duration: If an error is quickly detected and corrected, it can limit the serious consequences. However, if the problem is ignored or diagnosis is delayed, it can worsen the condition of the transmission and cause more serious problems.
3. Consequences for the gearbox: If P0758 is not corrected promptly, it can lead to additional damage inside the transmission, such as increased wear on parts and gear shifting at inopportune times. This, in turn, may require more expensive transmission repairs or replacement.
4. Safety: An improperly functioning transmission can increase the risk of an accident, especially if the vehicle changes gears unexpectedly or loses power at the wrong time.

Overall, the P0758 code should be taken seriously and immediate diagnosis and repair is recommended to avoid further problems and ensure the safe and reliable operation of your vehicle.

What repair will help eliminate the code? P0758?

Fixing a P0758 code usually involves several repair and diagnostic steps. Workflows may vary depending on the vehicle make and model and the cause of the error. Here are typical repairs that may help resolve the P0758 code:

1. Diagnostics using a scanner: First, the mechanic will connect an OBD-II scanner to diagnose and determine the exact source of the problem.
2. Checking the transmission fluid level: Checking the transmission fluid level and condition is important because low fluid or contaminated fluid can cause an error.
3. Checking wiring and connectors: The mechanic will check the wiring and connectors associated with the shift solenoid B for damage, corrosion, or breaks.
4. Checking the transmission valve body: The transmission valve body may need to be inspected for defects.
5. Checking Shift Solenoid B: The mechanic will check the solenoid itself for proper operation.
6. Checking hydraulic paths: Some repairs may require checking the hydraulic paths inside the transmission.
7. Replacement parts: Depending on the diagnostic results, the shift solenoid B, wiring, connectors, fluid, or other parts may need to be replaced or repaired.

What is P0758 Engine Code [Quick Guide]

P0758 – Brand-specific information

Code P0758 is related to the shift solenoid in vehicles with automatic transmission. Here are some car brands and their interpretations of the P0758 code:

1. Toyota / Lexus: P0758 means “Shift Solenoid B Electrical.”
2. Ford / Mercury: Code P0758 may refer to “Shift Solenoid B Electrical.”
3. Chevrolet / GMC / Cadillac: In this group of vehicles, P0758 may stand for “Shift Solenoid B Electrical.”
4. Honda/Acura: P0758 may be related to “Shift Solenoid B Circuit Electrical.”
5. Dodge / Chrysler / Jeep / Ram: For this group of vehicles, the P0758 code may indicate “2/4 Solenoid Circuit.”
6. Hyundai/Kia: Code P0758 stands for “Shift Solenoid 'B' Electrical.”
7. Volkswagen / Audi: P0758 may be related to “Shift Solenoid B Electrical.”

Please note that the exact meaning of the P0758 code may vary depending on the specific model and year of the vehicle. To accurately diagnose and fix the problem, it is important to conduct a detailed scan of the car, taking into account its make and model.