Automotive troubleshooting often involves deciphering a series of error codes your vehicle generates when it detects an issue. One such error code that can appear is the P0868, which points to a problem with the transmission fluid pressure. Here is a comprehensive guide on “How do I fix code P0868?”
What Does Engine Code P0868 Mean?
Before we delve into the solutions, it’s important to understand what this code signifies. The DTC code P0868 indicates a transmission fluid pressure issue that is lower than the manufacturer’s specification. This condition can lead to severe transmission damage if not addressed promptly.
What Causes the P0868 Code?
The P0868 error code, which indicates low transmission fluid pressure, can be triggered various issues. The breakdown of the most common causes are below:
1. Low Transmission Fluid Level
The simplest and most common cause is a low transmission fluid level, which might be due to a leak or insufficient fluid added during the last top-up.
2. Leaky Transmission Lines or Seals
Leaky transmission lines, seals, or gaskets can cause a drop in fluid pressure as they allow the fluid to escape from the system. It can be due to wear and tear or damage from road debris.
3. Blocked or Dirty Transmission Filter
A blocked or dirty transmission filter restricts the fluid flow, causing a decrease in pressure. This generally happens due to a buildup of debris or due to the disintegration of the transmission components over time.
4. Faulty Transmission Fluid Pressure Sensor
The transmission fluid pressure sensor can malfunction, sending incorrect signals to the vehicle’s computer and triggering the P0868 code. This could be due to sensor wear, faulty wiring, or electrical problems in the circuit.
5. Malfunctioning Transmission Pump
The pump is responsible for maintaining the right pressure level in the transmission system. If it fails or starts to wear out, it won’t be able to generate enough pressure, leading to the triggering of the P0868 code.
6. Internal Transmission Damage
This includes damage to the transmission’s internal components like valves, clutches, or bearings, which might lead to a drop in pressure. This issue generally occurs due to prolonged use, lack of maintenance, or use of the wrong type of transmission fluid.
7. Use of Incorrect Transmission Fluid
Using the wrong type of transmission fluid can cause damage to the internal components or lead to improper fluid flow, which might result in low pressure.
8. Faulty Transmission Control Module (TCM)
A malfunctioning TCM can incorrectly interpret signals or fail to control the transmission properly, leading to issues such as low fluid pressure.
9. Transmission Overheating
If the transmission overheats, it can cause damage to the internal components, which might lead to low fluid pressure.
Symptoms of Low Transmission Fluid Pressure
Low transmission oil pressure in a vehicle can manifest through several noticeable symptoms. Identifying these signs early on can save you from costly repairs in the future. Here are some of the common symptoms of low transmission oil pressure:
1. Delayed or Erratic Gear Shifting
When the transmission fluid pressure is low, the transmission might take longer to engage the gear. You may notice:
- Delayed Engagement: When there’s a significant pause before the vehicle starts moving.
- Erratic Shifting: The transmission might shift unpredictably or at the wrong times.
2. Transmission Slipping
This symptom is characterized by the transmission seeming to ‘slip’ into other gears during driving, usually accompanied by a notable change in the engine’s tone. This occurs because the low pressure doesn’t provide enough force to keep the gears engaged.
3. Overheating
Transmissions rely on fluid to cool their internal components. Low fluid pressure can lead to inadequate cooling and consequently, overheating. Overheating might manifest as:
- Smell of Burning Transmission Fluid: A distinct, unpleasant smell.
- Warning Lights: Transmission temperature warning lights on the dashboard.
4. Transmission Fluid Leaks
A leak in the transmission system can cause low fluid pressure. Signs of a leak include:
- Puddles of Fluid under the Vehicle: Red or brownish transmission fluid on the ground where the vehicle was parked.
- Low Fluid Levels: Checked through the transmission fluid dipstick.
5. Transmission Noise
Low fluid pressure can lead to inadequate lubrication of the transmission components, resulting in unusual noises like:
- Whining or Humming: Usually emanating from the transmission area.
- Clunking: Heard, especially during gear changes.
6. Transmission Warning Lights
Modern vehicles have sensors that monitor the transmission fluid pressure. Low pressure will trigger warning lights or messages on the dashboard, indicating a problem with the transmission system.
7. Poor Fuel Efficiency
Low transmission fluid pressure can cause the transmission to work inefficiently, resulting in decreased fuel efficiency as the engine has to work harder to transmit power.
8. Complete Transmission Failure
In the worst case, prolonged driving with low transmission fluid pressure can lead to total transmission failure, where the vehicle will not move at all, necessitating a complete transmission rebuild or replacement.
How Do I Fix Code P0868?
Now, let’s go through the steps you can take to diagnose and fix the code P0868.
Step 1: Check the Transmission Fluid Level
- Park your Car on a Level Surface: Ensure the car is parked on a level surface.
- Check the Fluid Level: Check the fluid level using the transmission fluid dipstick. Refer to the vehicle’s manual for guidance.
- Top-Up Fluid Level if Necessary: If the fluid level is low, top it up to the correct level using the recommended transmission fluid.
Step 2: Inspect for Fluid Leaks
- Inspect the Ground: Check for signs of fluid leaks underneath the vehicle.
- Check the Transmission Lines: Examine the transmission lines for any signs of leakage.
- Inspect Gaskets and Seals: Check gaskets and seals for signs of wear and replace them if necessary.
Step 3: Examine the Transmission Fluid Pump
- Listen for Noises: Unusual noises from the transmission could indicate a faulty pump.
- Inspect the Pump: If necessary, remove the pump to check for damage or wear.
Step 4: Replace the Transmission Filter
- Locate the Filter: Refer to the vehicle’s manual to locate the transmission filter.
- Replace the Filter: If the filter is blocked or dirty, replace it with a new one to restore fluid pressure.
Step 5: Check the Electrical Components
- Inspect the Wiring: Check the wiring connected to the transmission for signs of damage.
- Test the Sensors: Use a diagnostic tool to check the functioning of the pressure sensors.
- Replace Faulty Components: Replace any damaged wiring or faulty sensors as necessary.
Step 6: Reset the Error Code
- Use a Diagnostic Tool: Once the issue is fixed, use a diagnostic tool to reset the error code.
- Test Drive the Vehicle: Take a short test drive to verify if the error code has been resolved.
Remember, working on a transmission can be complex, and if you are not comfortable doing it yourself, it’s always best to seek professional help.
Conclusion
Resolving the error code P0868 involves a series of inspection and replacement procedures around the transmission fluid pressure system. It is always recommended to address this error promptly to prevent potential damage to the transmission system. If in doubt, seeking professional help is advisable to ensure the longevity and functionality of your vehicle’s transmission system.