DIY Electrical Testing - A few things to do to help yourself while waiting for help!



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Dec 19, 2015
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This post is for your information only. Only do repairs you are comfortable doing. If you have warranty, take it to dealer(if you tamper with things it may void your warranty) Videos are not VW/Audi cars, but same principles.

First and for most.. do auto scan. INCLUDE IT IN YOUR POST.

Most faults are going to be electric or control modules issues. Control module issues can be related to bad coding, but more then likely it could be a issue down the line that is causing it...yep, electrical. So this post is to help you diagnose some electrical problems. Modules are expensive and easy to mess up if you are not familiar with them. Be cautious.

If you have a fault that involves electric issues- check all fuses, grounds. Don't go pulling all your fuses out, in some vehicles this can cause other issues.
***NOTE:if you use a test light one thing to be aware of when testing using a (+) is that many components in todays vehicles are (-) Switched and require only 5 VDC-RV to activate. It is possible (and probable) that device damage may occur. Especially to PCM/ECM and related CAN Modules. ALWAYS perform (+) testing with the ignition OFF and keys in POCKET to prevent such damage on 2008 and later vehicles.

if you see any codes that has "Intermittent" - means it was a clinch in the system, it may not be a issue any more but is stored . clear faults. recheck codes after driving 100 miles(don't go out and drive a 100 miles just to test, just do your everyday driving, check codes in a week) see if they return. you may have a loose connecting.

Power Supply Terminal 30
P1602 - 002 - Voltage too Low - Intermittent -- could be you disconnected battery or drained battery. clear codes, check scan. Remember, lots of issues with electrical can be caused by a bad or low voltage battery aswell.

Test you battery..

Test Alternator

No crank/start problems - test starter

Find a short in electrical

check relays

Hope that helps. Remember, this is FYIO. only do diagnosing or repairs you are comfortable doing.
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Benevolent Dictator
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Jan 29, 2014
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Moved to How-To's and Tips.