Symptom Diagnosis

Symptom checks cannot be used properly unless the problem occurs while the vehicle is being tested. To reduce diagnostic time, ensure basic diagnostic procedures in the BASIC TESTING article and self-diagnostic steps in the TESTS W/CODES article were performed before diagnosing a symptom. Symptom checks are listed in order of probability, ease of accomplishment, and accessibility. Symptoms available for diagnosis are as follows:

• No Crank
• Hard Start/Long Crank
• Stall After Start
• No-Start/Normal Crank
• Slow Return To Idle
• Idle Surge, Runs Rough Or Misses
• Fast Idle, Diesels/Runs On
• Low/Slow Idle, Stalls/Quits
• Stalls/Quits, Hesitation/Stumble
• Runs Rough/Misses
• Surges
• Backfires
• Loss Of Power
• Spark Knock
• Poor Fuel Economy
• Emissions Compliance
• Warning Indicator Lights
• High Oil Consumption
• Cooling System Runs Hot
• Cooling System Runs Cold
• Exhaust Smoke Or Smell
• Fuel Odor
• Engine Noise
• Vibration