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P0068 Code – What Does It Mean & 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

P0068 shows up when there are discrepancies in Mass Air Flow (MAF), Manifold Absolute Pressure (MAP), and Throttle position sensor (TPS) voltage values.

Meaning

P0068 is a Diagnostic Trouble Code that shows when there is Throttle Position Correlation for MAP/MAF. It reflects a discrepancy in the three sensors like MAF, MAP, and TPS. If reading from any of these sensors differentiates from the other sensor, then the Powertrain Control Module (PCM) sets the OBD-II trouble code: P0068. 

The MAF and MAP sensors check the air volume that comes through the intake manifold. The throttle position sensor then evaluates the butterfly valve to regulate the air coming in from the intake manifold. 

Causes

Code P0068 can show up due to the following reasons:

  • Leakages in the intake manifold
  • Issues with the sensors (TPS, MAF, MAP)
  • Airflow Obstruction
  • Issues with electrical connectors
  • Concerns with PCM (Powertrain Control Module)

Symptoms

  • Check Engine Light will show up
  • Engine Idling is rough
  • Rough Acceleration
  • Fuel inefficiency
  • Difficulty in starting the engine

Diagnosis

 You must immediately diagnose the causes of the P0068 code. However, this code could be related to multiple complexities within three sensors of the engine. Therefore, we recommend that you should take your vehicle to a qualified technician for a thorough diagnosis. If you would still like to perform a DIY investigation, the following steps can help:

  • Gather the tools like essential hand tools, multimeter, OBD Scanner 
  • First, try to reset the code, and further to resetting, try driving for a short distance to check if the code is not showing again.
  • Check if the OBD scanner is showing any other code in addition to P0068. If there are any other codes related to TPS, MAP, or MAF, run diagnosis to evaluate issues with them first before checking P0068
  • Assess the air filter and if you find it dirty, replace it
  • Check if the sensor connectors are loose or if there is broken wiring 
  • Inspect the vacuum lines and intake connections to ensure lines are connected, and air leakage is not there
  • Check for loose pipe clamps between the MAF sensor and throttle body
  • See if there is visible corrosion on sensors 
  • Fire up the engine to assess if there is any hissing sound

Common Mistakes

  • Concluding that sensors are faulty and replacing them without a complete inspection
  • Replacing parts of ignition or fuel system considering misfire an issue

How Serious is This?

P0068 does not impact your driving immediately, and therefore, many car owners make the mistake of considering it a non-serious issue. P0068 is a serious concern that can affect your car engine’s performance in the long run. It could even result in rough interim performance, and if this continues for a long time, it could further damage the engine or lead to unavoidable, expensive repairs.

What Repairs Can Fix the Code

Due to the complexity of the issues related to this code, you must visit a professional mechanic who can investigate the issue thoroughly and take necessary repair / reset actions to fix the code. Below are some repair fixes: 

  • Vacuum leaks repairs
  • Replacing sensors connectors
  • Mass airflow sensor or manifold absolute pressure sensor repair
  • Replacement of faulty wiring
  • Check for clogging and dryness. 
  • Checking of all three sensors for voltage and resistance 
  • Inspect the three sensors for damage or corrosion. Cleaning of debris
  • Replacement of sensors 
  • Check if there is an issue with Powertrain Control

Finally, a mechanic should assess using OBD 2 scanner again if the code is not showing anymore.

Related Codes

  • P0550 - Power Steering Pressure Sensor Circuit Malfunction
  • P0335 - Crankshaft Position Sensor "A" Circuit Malfunction

Conclusion

While code P0068 does not seem to be serious at first, it could lead to severe problems in the long run. It could also impact the fuel efficiency and could eventually lead the engine to stall. Therefore, if you see this code, we recommend that you immediately take your vehicle to your mechanic to see the possible causes of this code. If you wish to try some DIY techniques, you can refer to the recommendation above and see if you can perform some actions.

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