P178E Function limitation due to excessive temperature

Fault code P178E Function limitation due to excessive temperature is related to the problem with ride height control system. In ride height control system airmatic motor (Compressor) create air and send it to the air tank reservoir and shocks absorber with the help of valve body (valve block) . Valve body fill air with pressure to shocks absorber and air reservoir tank. When there is any leak directed aimatic motor have to create more air to complete requirement. Due to which airmatic motor (Compressor) get hot. There is a sensor fitted in motor called as temperature sensor which sens the temperature of motor when temperature exceed, ride height control module shut off airmatic motor for safety reason. Due to excessive amount of air production sensor measure more heatness of motor send this signal to ride height control module. When ride height control module receive this signal from temperature sensor it store Fault code P178E Function limitation due to excessive temperature .

Also there could be problem with temperature sensor or its wiring harness. It might be possible that temperature sensor is also faulty or its wiring harness is open.

airmatic motor (compressor)

Cause of P178E Function limitation due to excessive temperature :

  • Leak at airmatic motor (compressor).
  • Leak at valve body or valve block.
  • At the top of shocks absorber leak detected.
  • Air pipe line leaky.

Symptoms :

  • Height of vehicle will get lower.
  • Airmatic warning light will illuminate on cluster meter.
  • Fault code will store in ride height control module.
  • Height could be lower from one side which side’s shocks or pipe is leak.

How to trouble shoot:

  • mechanic need to find leak at step by step as leak can be anywhere like, airmatic motor or compressor,valve body or valve block, air reservoir tank, air pipe line, shock absorbers.
  • 1) check leak at airmatic compressor if require then open it, operate it out side the vehicle the power supply and check leak.
  • 2) check leak at its airmatic reservoir tank.
  • 3) then check leak at valve body from where all pipe goes to shocks absorber.
  • 4) Also check shocks absorber its self for leak.
  • when found leak than close leak. most probably leak is present somewhere due to which this fault code store in ride height control module.
  • if did not find any leak than check for temperature sensor for its failure or its wiring harness for any damage. if found any damage at wiring harness than repair it. if not than go to check temperature sensor and airmatic motor. some time when when airmatic motor come in contact with water. water get store at place of temperature sensor. due to which fault code may store in control module.
  • if require than change temperature sensor that can solve problem.

Solution of P178E Function limitation due to excessive temperature :

  • Repair leak.
  • Replace leak shock absorber.
  • Repair airmatic compressor.
  • Repair or replace leak valve block.
  • Replace faulty temperature sensor .

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