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P0868 – What Does It Mean and How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.

Definition

P0868 is an OBD-II Code that refers to Transmission Fluid Pressure Low

Meaning

A P0868 code is a general diagnostic trouble code that occurs when the ECM/PCM detects that the transmission fluid pressure is too low or below the acceptable range or value. Transmission fluid is a hydraulic oil that lubricates, cleans, and cools the moving parts inside the transmission. A sensor is used to monitor the fluid pressure and sends a signal to the ECM/PCM. 

If the PCM detects that the pressure is too low or outside of the acceptable range, it will trigger the P0868 code and illuminate the Check Engine Light.

Causes

Common causes for this code include:

  • Low transmission fluid level
  • Dirty transmission fluid
  • Faulty transmission pressure sensor or circuit
  • Leaking transmission
  • Restricted transmission filter
  • Faulty transmission pump

Symptoms

The symptoms of a P0868 code are:

  • Illuminated Check Engine Light
  • May not engage some, or any gears
  • Transmission slippage may occur
  • Transmission may overheat, smoke and enter limp mode
  • Other transmission related codes might be present

Diagnosis

To diagnose a P0868 DTC code, a technician would:

  1. Scan for codes in the ECM and look at the freeze frame data for failure.
  2. Visually inspect all the wiring and connectors in the circuit.
  3. Check for transmission fluid leaks.
  4. Check the transmission fluid level and condition.
  5. Check the operation of the transmission pressure sensor and circuit.
  6. Perform a road test to check for drivability concerns, while monitoring data with a scan tool.

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a P0868 code:

  • Not thoroughly inspecting all the wiring and connectors for damage.
  • Not checking for transmission fluid leaks.
  • Not checking the transmission fluid level and condition.
  • Assuming that because there are no drivability concerns, the code must not be affecting the vehicle.

How serious is this?

A P0868 code is an extremely serious as you will not only experience drivability issues. If the internal transmission components don't have enough fluid pressure to operate, you can seriously damage them.

What repairs can fix the code?

The following are solutions that may fix this problem:

  • Broken or faulty wirings must be repaired or replaced
  • Bad or damaged connectors must be replaced
  • Transmission fluid leaks must be repaired
  • Dirty transmission fluid should be flushed and replaced
  • Faulty transmission pressure sensor or circuit should be replaced
  • Restricted transmission filter should be replaced
  • Faulty transmission pump should be replaced

Related codes

A P0868 is related to and may be accompanied by the following codes:

P0867 - Transmission Fluid Pressure High

P0869 - Transmission Fluid Pressure Sensor/Switch "B" Circuit Intermittent

P0870 - Transmission Fluid Temperature Sensor "A" Circuit Low Input

P0871 - Transmission Fluid Temperature Sensor "A" Circuit High Input

P0872 - Transmission Fluid Temperature Sensor "B" Circuit Low Input

P0873 - Transmission Fluid Temperature Sensor "B" Circuit High Input

P0874 - Upshift Delay Too Short

P0875 - Downshift Delay Too Long

Conclusion

In conclusion, the P0868 code is a diagnostic trouble code that refers to a problem with the transmission fluid pressure being too low. This code can cause serious drivability issues and damage to the transmission if not diagnosed and repaired promptly. To diagnose this code, a technician would start by checking for transmission fluid leaks, followed by inspecting the wiring and connectors in the circuit. The transmission fluid level and condition should also be checked. The operation of the transmission pressure sensor and circuit should be tested next. 

Finally, a road test should be performed to check for drivability concerns while monitoring data with a scan tool. Common mistakes when diagnosing this code include not thoroughly inspecting all the wiring and connectors for damage and not checking for transmission fluid leaks.