Pre-code is a term describing boost cut by the ECU before logging a Volvo DTC - Diagnostic Trouble Code

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“Pre-code” is a term I just invented to describe a situation where my Volvo has determined that something is irregular, but before it logs a diagnostic trouble code (DTC). Also, by definition, a pre-code is something that happens before a Check Engine light, since a DTC is a requirement of a Check Engine light.

I can tell when my 850 T5 is in a pre-code condition because it cuts my 850’s boost in half. I can easily feel this when accelerating, and can measure it because I installed a boost gauge in my Volvo 850.

5 Replies to “Pre-code”

  1. My s60 2001 all wheel drive is beeping when i start it up and the numbers 067 come up on my console….what does this mean?

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