Documenting Intermittent Concerns Properly
Documenting Intermittent Concerns
An intermittent concern is one that does not happen every time. The check engine light comes on during highway driving but is off when the customer drops the car off. The vehicle stalls at random but starts right back up. The noise only happens on cold mornings. These are real concerns, but if you cannot duplicate them during your test, you need to document everything properly so the next tech — or you on the next visit — has something to work with.
What to document when you cannot duplicate
Write exactly what the customer described, including every condition: time of day, temperature, speed, engine temperature, road surface, how long they had been driving, what accessories were in use. Pull all stored and pending codes — document every single one, even if they seem unrelated. Record freeze frame data for every code. Check for technical service bulletins that match the symptom. Document all of this on the repair order even if you are returning the vehicle without a repair. This is not wasted time. This is building the diagnostic record.
Setting up for the next visit
If the concern is electrical and intermittent, consider whether the vehicle can be sent home with a data logger or a flight recorder mode enabled on the scan tool. Some advanced scan tools can record data continuously and flag the moment a parameter goes out of range. If that is not available, instruct the customer to note the exact time and conditions when the concern occurs so the freeze frame and event log can be cross-referenced. The more data collected over time, the closer you get to catching the fault in the act.
Why documentation matters here more than anywhere
Without documentation, every visit for an intermittent concern starts from zero. The tech has no history to reference. They run the same tests, find nothing, and return the car again. With thorough documentation from each visit, the diagnostic picture builds over time. On visit one you documented the customer's description and freeze frame showing 65 mph at operating temperature. On visit two the concern happened at 70 mph and you now have a second freeze frame. By visit three you have enough data to identify the pattern and isolate the fault. Documentation turns multiple inconclusive visits into a cumulative diagnostic process that eventually solves the problem.