Engine-CodesJeep – P0840 Jeep

P0840 Jeep Code - Transmission Fluid Pressure Sensor/Switch 'A' Circuit

Quick Answer

The P0840 code for Jeep vehicles indicates a problem with the Transmission Fluid Pressure Sensor/Switch 'A' Circuit. Common causes include Faulty transmission fluid pressure sensor/switch, Wiring issues in the sensor circuit, Transmission control module failure. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0840 Jeep indicates Transmission Fluid Pressure Sensor/Switch 'A' Circuit.
Common causes
Common causes include Faulty transmission fluid pressure sensor/switch, Wiring issues in the sensor circuit, Transmission control module failure.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Table of contents Created and updated by William Orellana on Aug 25, 2024
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Code P0840 Jeep Description

The P0840 code for Jeep vehicles indicates a problem with the Transmission Fluid Pressure Sensor/Switch 'A' Circuit. This sensor is responsible for monitoring the hydraulic pressure within the transmission system. When this sensor detects an issue with the pressure, it sends a signal to the vehicle's engine control module (ECM), which triggers the illumination of the check engine light. This code can affect the vehicle's performance by causing erratic shifting, transmission slipping, or even the transmission going into limp mode, where it only operates in one or two gears.

OBDII Code P0840 Jeep - Transmission Fluid Pressure Sensor/Switch 'A' Circuit
P0840 Jeep Code - Transmission Fluid Pressure Sensor/Switch 'A' Circuit

Common Causes of P0840 Jeep

  1. Faulty transmission fluid pressure sensor/switch
  2. Wiring issues in the sensor circuit
  3. Transmission control module failure
  4. Low transmission fluid levels
  5. Contaminated or degraded transmission fluid

Symptoms of P0840 Jeep

  1. Check engine light illuminated
  2. Erratic shifting
  3. Transmission slipping
  4. Transmission going into limp mode
  5. Harsh or delayed shifting

How to Fix P0840 Jeep

  1. Begin by using a diagnostic scanner to confirm the P0840 code and identify the specific issue.
  2. Inspect the transmission fluid level and condition. Top up the fluid if necessary and replace it if it is contaminated.
  3. Check the wiring and connections in the transmission fluid pressure sensor/switch circuit for any damage or corrosion. Repair or replace as needed.
  4. Test the transmission fluid pressure sensor/switch using a multimeter to determine if it is functioning properly. Replace the sensor if it is faulty.
  5. Clear the diagnostic trouble codes, reset the ECM, and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P0840 Jeep

The typical repair costs for addressing the P0840 code on a Jeep vehicle can range from $150 to $500, depending on the specific cause of the issue and the cost of parts and labor in your area. It's important to note that diagnosis time and labor rates at auto repair shops can vary, so it's advisable to get a few quotes before proceeding with the repairs.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

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