What is the P0703 fault code number? What is Torque Converter/Brake Switch A Circuit Malfunction? How can you fix P0703 fault code What are the causes and symptoms of the P0703 error code?
What is the P0703 fault code? What does it mean?
The code P0703 is set when the powertrain control module, PCM/ECM, detects a problem with the brake sender circuit B or if the voltage signal coming from the brake switch does not match specifications. This code disables brake lights, cruise control system, and transmission torque converter locking system. This code will only be displayed on automatic transmission vehicles.
Since the 1980s, automatic transmissions can be electronically controlled. The PCM integrates a transmission controller to manage OBD-II-equipped vehicles. Some vehicles use a standalone TCM (transmission control module) that communicates via the CAN bus with the PCM and other modules. The fluid coupling device that connects the engine and the transmission is the torque converter. While the vehicle is moving, it transfers engine torque to its input shaft. It absorbs the engine torque when the vehicle is stopped while the engine is idle using the fluid coupled clutch system. This operation allows the engine’s idle to continue without stalling.
OBD-II-equipped vehicles have a lock-up torque converter that allows the engine to lock onto its input shaft in certain conditions. This occurs when the transmission shifts into high, or when the vehicle has reached a desired speed. Lock-up mode allows the engine and gearbox to work in a 1:1 ratio. This system ensures optimal engine performance and fuel efficiency.
The engine speed should drop to a minimum level before torque converter lockup is disengaged. The engine will shut down if it is not. Brake pedal application is one special signal that the PCM uses for overriding torque converter lockup. The brake pedal is depressed and the brake lever applies pressure on the brake switch to close one or more circuits. These circuits close when the brake pedal is depressed. The stop lamps turn on, and a second signal goes to the PCM. This signal alerts the PCM that the brake pedal is depressed and that it must be deactivated.
The brake switch circuits can be referred to as the P0703 Code. This code will be saved when the transmission control unit (TCM)/PCM detects an abnormal reading in the brake lamp voltage and resistance.
There are many vehicles that can be affected by the P0703 fault code, including models from Honda, Mazda, Mercedes-Benz, Volkswagen and Jeep, Hyundai, Toyota, Ford and Mercedes.
What causes the P0703 Fault code?
Here are some reasons why P0703 should be set.
- – Incorrectly or defectively adjusted brake switches (brake switches)
- – Stop lamp circuit problems (bad wiring, loose connectors or open circuits).
- – Blown Stop Lamp Circuit Fuse
- – Blown brake lamp sockets
- Blown taillight bulb
What are the symptoms of the P0703 Fault Code?
The following symptoms may be experienced by anyone who has a vehicle coded P0703.
- – Illumination for the check engine light
- – Inoperative brake light
- – Permanent brake lights
- Torque converter does not lock
- Vehicle stalling while decelerating/idling
- – Increased fuel consumption
- – Low engine performance
- – Irregular gear changes
- – Other related fault codes
How do I fix the P0703 fault code?
- – Replacing the broken brake switch
- – Repair of the wiring and connectors for the stop lamp circuit
- Repair of short or open circuits in the stop lamp circuit
- – Replacing a blown fuse
- – Replacing a blown taillight bulb
How Serious Is the P0703 Fault Code
The smooth operation of many systems is dependent on the brake switch. Bad brake switches can cause brake lights to not work or remain on, which can be dangerous. A faulty brake switch can also cause the torque convertor to not lock up, disengage, or fail to engage. This could lead to stalling issues and other driving issues. This can also cause the cruise control to not work properly and stop it from activating. It is important to address P0703 immediately and have it repaired as soon as possible.
