P0840 Code - Transmission Fluid Pressure Sensor/Switch 'A' Circuit
Quick Answer
The Transmission Control Module (TCM) monitors the Transmission Fluid Pressure Sensor/Switch signal. Common causes include Faulty Transmission Fluid Pressure Sensor/Switch 'A', Transmission Fluid Pressure Sensor/Switch 'A' harness is open or shorted, Transmission Fluid Pressure Sensor/Switch 'A' poor electrical connection. 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 indicates Transmission Fluid Pressure Sensor/Switch 'A' Circuit.
- Common causes
- Common causes include Faulty Transmission Fluid Pressure Sensor/Switch 'A', Transmission Fluid Pressure Sensor/Switch 'A' harness is open or shorted, Transmission Fluid Pressure Sensor/Switch 'A' poor electrical connection.
- 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.
Code P0840 Description
What are the Possible Causes of the DTC P0840?
- Faulty Transmission Fluid Pressure Sensor/Switch 'A'
- Transmission Fluid Pressure Sensor/Switch 'A' harness is open or shorted
- Transmission Fluid Pressure Sensor/Switch 'A' poor electrical connection
- Transmission Valve Body
How to Fix the DTC P0840?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0840 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Information for Specific Makes
- P0840 Chrysler — Transmission Fluid Pressure Sensor/Switch 'A' Circuit
- P0840 Dodge — Transmission Fluid Pressure Sensor/Switch 'A' Circuit
- P0840 Infiniti — Transmission Fluid Pressure Sensor 'A'
- P0840 Jeep — Transmission Fluid Pressure Sensor/Switch 'A' Circuit
- P0840 Mercedes-Benz — Transmission Fluid Pressure Sensor/Switch 'A' Circuit
- P0840 Nissan — Transmission Fluid Pressure Sensor 'A'
Frequently Asked Questions about P0840 Code
1. What are the common symptoms of OBDII code P0840?
- Common symptoms include harsh shifting, transmission slipping, transmission not shifting into gear, and illuminated transmission warning light.
2. What can cause the OBDII code P0840 to trigger?
- The code P0840 is typically triggered by a faulty transmission fluid pressure sensor/switch 'A', wiring issues, low transmission fluid levels, or a malfunctioning transmission control module.
3. How serious is OBDII code P0840?
- OBDII code P0840 can lead to transmission issues and potentially cause further damage if not addressed promptly. It is recommended to have the issue diagnosed and repaired as soon as possible.
4. Can I continue driving with OBDII code P0840 present?
- It is not recommended to continue driving with OBDII code P0840 present, as it can lead to transmission problems and potential safety hazards. It is best to have the issue resolved before driving the vehicle again.
5. How can I diagnose the cause of OBDII code P0840?
- Diagnosis typically involves using a scan tool to check for the code, inspecting the transmission fluid level and condition, testing the transmission fluid pressure sensor/switch 'A', and checking the wiring for any faults.
6. Can I repair OBDII code P0840 myself?
- While some DIY enthusiasts may attempt to repair OBDII code P0840 themselves, it is recommended to have a qualified mechanic diagnose and repair the issue to ensure proper resolution and prevent further damage.
7. What is the typical repair for OBDII code P0840?
- The typical repair for OBDII code P0840 involves replacing the faulty transmission fluid pressure sensor/switch 'A', repairing any wiring issues, topping up or replacing transmission fluid, or addressing any underlying transmission control module problems.
8. How much does it cost to fix OBDII code P0840?
- The cost to fix OBDII code P0840 can vary depending on the cause of the issue, the extent of repairs needed, and labor rates in your area. It is advisable to obtain quotes from different mechanics to compare prices.
9. How long does it take to repair OBDII code P0840?
- The repair time for OBDII code P0840 can vary depending on the complexity of the issue and the availability of parts. In general, it may take a few hours to a day for the repair to be completed.
10. Can OBDII code P0840 be prevented?
- Regular transmission maintenance, such as fluid checks and changes as recommended by the manufacturer, can help prevent issues like OBDII code P0840. Additionally, addressing any transmission problems promptly can help prevent more serious issues from occurring.
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