Recreating The Fault

Recreating the fault is the first step in isolating cause of intermittent symptom. If FREEZE FRAME DATA is available, it may help in recreating condition(s) at the time of a Malfunction Indicator Light (MIL) DTC. Use the following conditions to aid in recreating an intermittent fault:

• Engine Type Conditions
  
  Engine temperature, RPM, load and engine speed (idle, acceleration, deceleration).
• Non-Engine Type Conditions
  
  Ambient temperature, moisture conditions and road conditions (smooth or bumpy).

In some cases intermittent failures can be diagnosed by selecting and monitoring PID values that are related to a specific fault area (symptom). For additional information, see SYMPTOM TESTING under TEST PROCEDURES in PIN VOLTAGE/PID VALUE CHARTS - TRUCKS article.