You won’t be surprised to hear that most businesses in any sector like to make money as quickly and as easily as possible.
You can hardly blame them. The ‘low hanging fruit’ has the sweetest taste as they say, but of course everyone wants the first pick.
This attitude means that they either turn away from more complex work that requires know-how and diagnostic skills, or they take the job on and then subcontract the job to someone else.
However, the work that other garages don’t want need not be any more difficult than routine jobs for technicians that are appropriately trained and know how to work smarter, not harder.
One of the most common reasons for cars to be passed through the trade is intermittent faults. By definition, they don’t show up all of the time and it is no wonder that some garages either don’t want to spend time on tracing where the problem lies, or (unfortunately all too often) try to fix it by replacing random parts without success.
Gather Information
The first step in diagnosing an intermittent fault is to gather as much information as possible about the problem. If the car has been sent to you from another garage, you might get a ‘broken telephone’ explanation that has been passed across two or more people. If possible, talk to the car owner or driver to get a detailed description of the symptoms, when they occur, and any other relevant details. Ask questions that can help you narrow down the issue, such as whether the problem occurs only when the car is hot or cold.
Of course, it may not be possible to speak to the end user of the vehicle directly, in which case, work through your diagnostic checks in the usual way, starting with a visual inspection, making sure connections are tight, that there is nothing obviously broken or missing, and that rodents haven’t made a nest in the air box, etc. All of this sounds elementary, but you might be surprised how many inexperienced technicians go down the fault code rabbit hole, without first checking the obvious.
Test Components, Replicate the problem
If you suspect that a particular component is causing the intermittent fault, don’t just assume it to be bad, but test it using a voltmeter or ohmmeter. Check for continuity and voltage drops across the component to ensure that it is functioning correctly.
The most challenging aspect of diagnosing an intermittent fault is replicating the problem. Try to recreate the problem by driving the car under similar conditions to when the fault occurred. This can help you identify any patterns or triggers that may be causing the issue.
Using a tool like an OBD logger might help you chase down those problems. Checking that readings produced by sensors are within spec can easily be checked against information provided by Autodata. You can also use the colour wiring diagrams to assist with chasing down loose connections and poor earthing points.
All of this will take time, but there is no problem on any car that cannot be resolved by an experienced technician working through a thorough diagnostic process. Indeed, there are number of garages all across Europe that make this kind of ‘out of the ordinary’ kind of work almost routine, and these people are always the ‘go-to’ specialist in their area, meaning that a majority of their work comes in through the trade, which has the added advantage that payment is generally swift and straight to account.
Once the intermittent fault has been identified and rectified, one should always allow a decent amount of time to test drive the car to ensure that the problem has been resolved and that there are no new warning lights that have been triggered during the repair process!
