SYMPTOM DIAGNOSIS
Symptom checks cannot be used properly unless the problem occurs while the vehicle is being tested. To reduce diagnostic time, ensure steps in BASIC TESTING and TESTS W/CODES articles 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
- «BASIC TESTING - 3.0L»(ref-23346)
- «TESTS W/CODES»(ref-23293)
- 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
INTERMITTENT PROBLEM DIAGNOSIS
Intermittent fault testing requires duplicating circuit or component failure to identify the problem. These procedures may lead to the computer setting a fault code which may help in diagnosis.
If problem vehicle does not produce fault codes, monitor voltage or resistance values using a DVOM while attempting to reproduce conditions causing intermittent fault. A status change on DVOM may indicate a fault has been located.
Use a DVOM to pinpoint faults. When monitoring voltage, ensure circuit has power applied to it. Significant changes on DVOM during test procedures indicate area of fault.
TEST PROCEDURES
Note. For information on connecting test equipment, see TESTS W/CODES article.