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Practical Diesel Tuning: Reflashing Precautions

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Reflashing Precautions


00:00 - When tuning an engine, there's always the risk of damage to the actual engine.
00:03 And most tuners can understand this risk.
00:05 With reflashing however a new risk is introduced and that is the risk that under certain conditions, it's possible to irreversably damage the ECU, requiring replacement.
00:15 Obviously if you're dealing with a sophisticated late model vehicle, this could come at a high price so some caution is required.
00:21 Typically the situations where you might get into trouble is if the battery voltage in the vehicle drops too low during the flash process, if the interface is disconnected part way through the reflash, or if your laptop runs flat or suffers a battery failure.
00:35 In any of these situations it's possible for the ECU to become unresponsive.
00:39 Even if this happens, all is not necessarily lost.
00:42 Often just attempting to reflash the ECU again will recover it.
00:46 Of course if we can avoid the situation entirely then it's going to involve a lot less stress and potential expense.
00:52 The first piece of advice here is to make yourself familiar with the specific reflashing instructions for the particular product that you're using.
00:59 The required procedures differ slightly from one manufacturer to the other and if there's anything specific that you need to be aware of, it's likely to be listed in the instructions.
01:08 Secondly, always make sure your laptop is fully charged if you're going to be tuning without main power connected.
01:15 And it pays to get in the habit of checking your battery level prior to beginning the flash procedure.
01:20 If you're tuning on a dyno then it makes sense to have your laptop connected to the main power.
01:23 However the likes of HPTuners specifically advise against this as it can cause a voltage offset between the laptop and the tuning module and can potentially damage the ECU.
01:32 Again, this is why it's so important to follow any specific instructions from the manufacturer of the product.
01:38 Most reflash procedures are completed in less than two minutes.
01:41 However in some vehicles this may take 15 minutes or more.
01:44 In addition to this, in some vehicles while the reflash is in progress, the cooling fans and other ancillary devices may run.
01:51 And this puts a reasonable current draw on the vehicle's battery.
01:55 If the battery voltage drops too low this can interrupt the reflash procedure and that's no good.
02:01 To reduce the risk of battery voltage dropping too low, it can be advisable to connect your car battery to a high current charger while the reflash is in progress.
02:09 if this is advisable for your particular vehicle, the manufacturer of the reflash software would suggest it in their instructions.
02:15 While damaging an ECU is a very real possibility, in my own career I've reflashed literally hundreds of ECUs from a wide range of manufacturers and only suffered a handful of unrecoverable failures.