B1991 – OBD-II DTC

OBD-II DTC B1991 – Pedal Forward / Rearward Potentiometer Feedback Circuit Short to Battery

DTC B1991 meaning

DTC B1991 refers to a diagnostic trouble code indicating a short circuit in the pedal forward/rearward potentiometer feedback circuit to the battery. This code is associated with the vehicle’s electronic control system, which monitors the position of the accelerator pedal. The potentiometer is responsible for providing feedback to the engine control module (ECM) regarding the pedal’s position, which is crucial for proper engine performance and emissions control.

DTC B1991 symptoms

Common symptoms associated with DTC B1991 may include:

• Illumination of the check engine light
• Unresponsive or erratic throttle behavior
• Reduced engine power or performance
• Difficulty in accelerating
• Potential stalling of the engine

DTC B1991 causes

Several factors can lead to the triggering of DTC B1991, including:

• A short circuit in the potentiometer wiring
• Faulty accelerator pedal position sensor
• Corroded or damaged electrical connectors
• Issues with the engine control module (ECM)
• Faulty ground connections

DTC B1991 seriousness

DTC B1991 is considered a serious issue as it can affect the vehicle’s throttle response and overall drivability. If left unaddressed, it may lead to unsafe driving conditions, including sudden loss of power or stalling. It is advisable to diagnose and repair this code promptly to ensure safe operation of the vehicle.

How to diagnose DTC B1991

To diagnose DTC B1991, follow these steps:

1. Use an OBD-II scanner to confirm the presence of DTC B1991.
2. Inspect the accelerator pedal position sensor and its wiring for any visible damage or corrosion.
3. Check the electrical connectors for secure connections and signs of wear.
4. Test the potentiometer using a multimeter to ensure it is functioning within specifications.
5. Examine the ground connections for continuity and integrity.
6. Clear the DTC and perform a road test to see if the code returns.

How to fix DTC B1991 step-by-step instructions

To fix DTC B1991, follow these step-by-step instructions:

1. Disconnect the battery to ensure safety while working on the electrical system.
2. Inspect and repair any damaged wiring or connectors related to the accelerator pedal position sensor.
3. If the potentiometer is faulty, replace it with a new one.
4. Ensure all ground connections are clean and secure.
5. Reconnect the battery and clear the DTC using an OBD-II scanner.
6. Perform a road test to verify that the issue has been resolved and the code does not return.

How to erase DTC B1991

To erase DTC B1991, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the ignition without starting the engine.
3. Navigate to the DTC menu on the scanner and select the option to clear or erase codes.
4. Confirm the action and wait for the scanner to complete the process.
5. Disconnect the scanner and start the vehicle to ensure the code does not reappear.

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