Guide To P0991 OBD Error Code Solutions

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Is the car’s transmission continuously slipping along with sluggish acceleration? Is there a problem of decreased fuel economy along with vehicle not shifting into gears? Is the car’s check engine light illuminated on the dashboard? All these are an indication towards a problematic transmission system and faulty pressure sensor, thus resulting in OBD code P0991 error getting stored in the powertrain control module (PCM).

The TFPS converts the mechanical transmission pressures into an electrical signal for the Powertrain Control Module (PCM) or Transmission Control Module (TCM). Typically, the PCM/TCM will then inform other controllers utilizing the vehicle's data communication bus. Diagnostic trouble code P0991 typically applies to all OBD-II equipped vehicles including but not limited to Nissan, Dodge, Chrysler, Honda, Chevrolet, GMC, Toyota, etc. but seems to be most commonly seen on Nissan vehicles. P0991 is set due to TFPS sensor circuit issue which includes any of the mechanical problem of the sensor circuit and related components as well. This cannot be overlooked in the troubleshooting stage, especially when dealing with an intermittent problem. Thus, the code getting flashed and stored in the PCM.

What causes this problem with the Transmission Fluid Pressure Sensor/Switch "E" Circuit Intermittent?

• Wrong level or dirty transmission fluid
• Failure inside transmission
• TFPS sensor circuit failure
• Blockage in transmission main control
• Faulty solenoid, torque converter clutch or internal blockage
• Faulty shift wirings or solenoids
• Faulty transmission control module (TCM)
• Torque converter clutch faulty

1. Engine Control Module - Faulty ECM can flash and store wrong OBD error. It’s better to get the faulty electricals replaced as soon as possible.
2. Powertrain Control Module - Damaged PCM hampers the engine timing. Find all the Powertrain related parts with us.
3. Diagnostic Tool - Find high grade diagnostic tools to detect the OBD error code from us. Visit us today to grab amazing deals.
4. Automatic Transmission Control Module - TCM can be at fault and can cause misinterpretation of data or not receiving it at all. Buy new modules and components from us.
5. Automatic Transmission Sensor - Check for faulty sensor and replace it immediately, if found guilty. Buy new transmission sensor now.

We at Parts Avatar Canada care for our customers, and that’s why we will help you to diagnose P0991 code by listing out some major symptoms. They are mentioned below as follows:

Common Symptoms

• Harsh shifting
• Transmission slippage
• Transmission overheating
• Decreased fuel efficiency
• An OBD stored code in the PCM
• Illuminated malfunction indicator lamp

Learn the ways with which you can correct this P0991 trouble code:

• Checking for transmission fluid or changing the transmission fluid
• Defective shift solenoid replacement
• Replacing or reprogramming Transmission Control Module
• TFPS circuit repair and replacement
• Faulty wiring and/or connectors for a damaged transmission control circuit replacement

However, if you face any issue then we have stocked a wide range of best priced Transmission, Pressure Sensor, ECM, Transmission Fluid Pressure Sensor/switch, Transmission Fluid, Pressure Switch, Mechanical Transmission, PCM, Malfunction Indicator Light Gear, Transmission Connector, Transmission Wiring, Electrical Grease, TFPS Sensor Wiring Harness Connector, Digital Voltmeter, Turn Key, TCM, Transmission Fluid, Transmission Pan, Transmission Clutch and more to help you out in fixing your car.

It is essential to diagnose this fault code. Here are some steps which a mechanic should follow for diagnosing the problem that triggered a P0991 code to be stored:

• Make use of a digital volt ohm meter (DVOM) for the complete test. Continue through the tests until the problem is confirmed. You will also need a basic OBD code scanner to reset the computer and erase the code.
• First check the level and quality of the transmission fluid. If the fluid is low, add more and retest the system.
• If the transmission fluid appears dirty or contaminated, and/or it smells burnt, the mechanic will flush the system, change the transmission fluid, clear the code, and retest once more. Inspect and test the transmission for internal mechanical problems, circuit problems, and issues with the shift solenoid. After each repair, they will clear all codes and retest the vehicle to see if the code appears again.
• Visually inspect the connector and wiring to the TFPS for scraping, rubbing, bare wires, burn spots or melted plastic and carefully inspect the terminals inside the connector. Check for burns and corrosion, and use electrical contact cleaner and a plastic bristle brush if cleaning of the terminals is needed. Let dry and apply electrical grease where the terminals contact.
• Check for the reference voltage to the sensor and the module in on and off condition, if accordance to the appropriate range as per the car’s specification, so as to check the faulty component and replace it immediately.
• Always retest the vehicle to see if the error code reappears or not. Also check for PMC faults and repair, replace or reprogram as required.

Common Mistakes When Diagnosing the P0991 Code

The most common mistake while diagnosing P0991 code is misdiagnosis of an engine misfiring issue or a problem with the vehicle’s driveline. If the system is not thoroughly inspected and diagnosed, it can also look like an internal transmission problem when it’s actually a much simpler and less expensive issue.