P0990 2018 GMC Sierra Code - Transmission Fluid Pressure Switch 5 Circuit High Voltage
Quick Answer
The P0990 diagnostic trouble code (DTC) for a 2018 GMC Sierra indicates a problem with the Transmission Fluid Pressure Switch 5 Circuit High Voltage. Common causes include Faulty transmission fluid pressure switch, Wiring issues or shorts in the circuit, Malfunctioning transmission control module (TCM). 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
- P0990 2018 GMC Sierra indicates Transmission Fluid Pressure Switch 5 Circuit High Voltage.
- Common causes
- Common causes include Faulty transmission fluid pressure switch, Wiring issues or shorts in the circuit, Malfunctioning transmission control module (TCM).
- 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.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
Code P0990 2018 GMC Sierra Description
The P0990 diagnostic trouble code (DTC) for a 2018 GMC Sierra indicates a problem with the Transmission Fluid Pressure Switch 5 Circuit High Voltage. This code is specifically related to the transmission system of the vehicle. The transmission fluid pressure switch is responsible for monitoring the hydraulic pressure within the transmission. When the switch detects a high voltage signal, it means that there is an issue with the pressure levels in the transmission fluid.
Common Causes of P0990 2018 GMC Sierra
- Faulty transmission fluid pressure switch
- Wiring issues or shorts in the circuit
- Malfunctioning transmission control module (TCM)
- Low transmission fluid levels
- Internal transmission damage or wear
Symptoms of P0990 2018 GMC Sierra
- Harsh shifting between gears
- Delayed engagement when shifting
- Transmission slipping
- Illumination of the check engine light
- Reduced fuel efficiency
How to Fix P0990 2018 GMC Sierra
- Begin by connecting a diagnostic scanner to the vehicle's OBD-II port to retrieve the specific trouble code and further diagnose the issue.
- Inspect the wiring harness and connectors associated with the transmission fluid pressure switch for any damage or corrosion. Repair or replace as necessary.
- Test the transmission fluid pressure switch using a multimeter to determine if it is functioning correctly. Replace the switch if it is found to be faulty.
- Check the transmission fluid level and condition. Top up or replace the fluid if needed.
- Clear the DTC from the vehicle's computer memory and test drive the vehicle to ensure the issue has been resolved.
Cost to Fix P0990 2018 GMC Sierra
The typical repair costs for addressing a P0990 code on a 2018 GMC Sierra can range from $200 to $500, including parts and labor. However, it is important to note that actual costs may vary depending on the specific diagnosis time and labor rates at auto repair shops. Rates can be influenced by factors such as location, vehicle make and model, and engine type. It is advisable to inquire with local auto repair shops for a more accurate estimate.
Need more information about the P0990 2018 GMC Sierra code?
Need more information on how to fix the P0990 2018 GMC Sierra code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P0990 2018 GMC Sierra code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P0990 2018 GMC Sierra Code
1. What does the OBDII code P0990 mean on a 2018 GMC Sierra?
P0990 indicates a high voltage issue in the Transmission Fluid Pressure (TFP) Switch 5 Circuit, which monitors transmission fluid pressure to help manage shifting.
2. What are the common symptoms of the P0990 code in a 2018 GMC Sierra?
Symptoms may include harsh or erratic shifting, failure to shift gears, transmission stuck in one gear, or the check engine light illuminating.
3. What are the potential causes of a P0990 code in a GMC Sierra?
Possible causes include a faulty TFP switch, damaged or corroded wiring in the circuit, a malfunctioning transmission control module (TCM), or low transmission fluid.
4. Can low transmission fluid cause a P0990 code?
Yes, low or contaminated transmission fluid can cause inaccurate pressure readings, leading to the P0990 code.
5. How is the P0990 code diagnosed?
A mechanic will typically use a scan tool to verify the code, inspect the wiring and connectors for damage or corrosion, check the TFP switch, and test the transmission fluid level and condition.
6. Is it safe to drive with a P0990 code on a GMC Sierra?
Driving with a P0990 code is not recommended, as it can cause further damage to the transmission and lead to unsafe driving conditions.
7. How much does it cost to fix a P0990 code on a 2018 GMC Sierra?
Repair costs vary depending on the cause, but replacing the TFP switch typically costs between $150 and $400, including parts and labor.
8. Can I fix the P0990 code on my GMC Sierra myself?
If you have experience with automotive repairs, you can inspect and replace damaged wiring or the TFP switch. However, diagnosing the issue accurately may require professional tools and expertise.
9. What happens if the P0990 code is ignored?
Ignoring the P0990 code can lead to worsening transmission problems, increased repair costs, and potential transmission failure.
10. Does clearing the P0990 code solve the issue?
Clearing the code with a scan tool may turn off the check engine light temporarily, but the underlying issue must be repaired to prevent the code from returning.
Discuss the causes and fixes for P0990 2018 GMC Sierra OBDII Code
Code P0990 2018 GMC Sierra comments
No comments found for this page.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.