Symptoms Diagnosis

Symptom checks cannot be used properly unless problem occurs while 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
• Stalls After Start
• No Start/Normal Crank
• Slow Return To Idle
• Rough Idle
• High Idle (Diesels/Runs On)
• Low Idle (Stalls On Deceleration)
• Hesitates Or Stalls
• Surge (On Acceleration Or Cruise)
• Backfires
• Loss Of Power
• Spark Knock
• Poor Fuel Economy
• Emissions Compliance
• Warning Indicator Lights
• Improper Transmission Shift
• High Oil Consumption
• Engine Runs Hot
• Engine Runs Cold
• Exhaust Smoke
• Fuel Pump Always On
• Gas Smell
• Sulfur Smell
• Engine Noise
• Vibration
• Climate Control (Lack Of Cooling)
• Climate Control (A/C Always On)
• A/C Does Not Go Off During WOT