Procedures for malfunction phenomenon simulation

NOTE:

The most difficult thing in troubleshooting is when there is no appearance of a malfunction phenomenon. In such cases, it is necessary to thoroughly analyze the malfunction information provided by the customer, and recreate the same conditions/environment of the customer's vehicle that existed when the malfunction occurred. Performing troubleshooting without confirming the malfunction phenomenon results in overlooking important points of repair procedures and making mistakes such that, ultimately, troubleshooting reaches a dead end.
For example, checking a malfunction that occurs when starting a cold engine with the engine already warmed-up, or checking for a vibration that occurs while driving on the road with the vehicle stopped limit the amount of checking and makes it impossible to identify the malfunction location.
Although there are malfunction with causes that cannot be reproduced, such as vibration, heat or entrance of water (moisture), the procedures indicated here for malfunction phenomenon reproduction are effective means in terms of providing for external causes when a vehicle is stopped.

Important points of malfunction simulation test

Although it is necessary to check the malfunction phenomenon using malfunction phenomenon reproduction procedures, it is necessary to also find the malfunction scope/location. Doing this requires you to narrow down the circuits containing the malfunction based on the malfunction phenomenon before performing tests and connect the tester beforehand. Afterwards, perform the malfunction reproduction procedures, and determine the circuits that are faulty and those that are normal during the testing while also checking the malfunction phenomenon. Refer to the malfunction phenomenon list for each system to narrow down the cause of the malfunction phenomenon. It is also necessary to use reproduction procedures that are according to the corresponding detection conditions/time of the corresponding diagnostic code in order to reproduce diagnostic code output.

Vibration method: For malfunctions thought to be caused by vibration
1. Parts and sensors
  1. Lightly tap by hand on the probable malfunctioning parts or use a similar method to vibrate them, and check if any malfunction occurs.
  NOTE: Subjecting relays to a strong impact can cause their points to IN open.
  
  Fig 1: Checking Sensors, Connectors And Wire Harnesses
  Courtesy of SUBARU OF AMERICA, INC.
2. Connectors
  1. Lightly shake the connectors up/down and right/left.
3. Wire harnesses
  1. Lightly shake the wire harnesses up/down and left/right, and check if any malfunction occurs.
  NOTE: It is especially important to check the connector bases, vibration fulcrums and areas passing through the body.
  
  Fig 2: Heating Up Or Cooling Down Using Hair Drier Or Coolant
  Courtesy of SUBARU OF AMERICA, INC.
Cooling/Heating method: For malfunctions thought to occur when cooled or heated
1. Heat up or cool down (using a hair drier or coolant) the probable malfunctioning parts, and check if any malfunction occurs.
  CAUTION:
  - If heating: Do not heat by +60°C (can be touched by hand) or more.
  - Do not heat or cool with the cover of the ECM or similar parts open so as to not directly heat or cool any electrical parts.
  NOTE: Coolant can be purchased at electrical parts stores.
Water sprinkling method: For malfunctions thought to occur during rain or high temperature
1. Sprinkle water on the vehicle and check if any malfunction occurs.
  CAUTION:
  - Do not sprinkle water directly on the engine room. Spray a fine mist of water to the front surface of the radiator to indirectly change the temperature and humidity.
  - Do not sprinkle water directly on electrical parts.
    
    Fig 3: Sprinkling Water On Vehicle
    Courtesy of SUBARU OF AMERICA, INC.
Other: For malfunctions thought to be caused during excessive electrical load
1. Create an excessive electrical load by operating various electrical parts such as the heater blower, headlights and rear defogger, and check if any malfunction occurs.