Help, mechanic doesn't recognize these codes
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Joined: Jun 2021
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From: Arizona
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Respectfully, the PCM does not send main power voltage to any of the Modules.
They have their own dedicated >fused< sources. One in the engine bay and one behind the passenger side kick panel.
The PCM only addresses them with control signals both directions on the Buses.
All the power comes from the Battery and Alternator system to the fuse panels.
The U 3013-16 is the important code. It has >detected the low voltage condition< and is not the fault. It is only reporting it.
The other two codes will clear when the low voltage condition is cleared.
Find out why the system voltage is low.
Good luck.
Respectfully, the PCM does not send main power voltage to any of the Modules.
They have their own dedicated >fused< sources. One in the engine bay and one behind the passenger side kick panel.
The PCM only addresses them with control signals both directions on the Buses.
All the power comes from the Battery and Alternator system to the fuse panels.
The U 3013-16 is the important code. It has >detected the low voltage condition< and is not the fault. It is only reporting it.
The other two codes will clear when the low voltage condition is cleared.
Find out why the system voltage is low.
Good luck.
I said the PCM send power to the BCM, which then sends power to the modules.
If the PCM goes bad, as mine has done in the past, the BCM can't properly power the modules and you'll get a crap ton of unrelated DTC messages.
Thread Starter
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From: Newfoundland
everything except the rear pads and oil is original, my grandfather bought it new and never replaced anything, I got it at 18,000 and it’s sitting at 120,000 I replaced the oil and pads lol
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There is a huge difference.
Just so we understand what I was trying to say. The Buses do not handle power of any sort, only digital signaling that does not result in any appreciable actual power.. They at terminated with resistors on each Bus end that would burn out if that were done.
Not arguing the point but clearing a difference of intended operational description.
Please give it some thought. Accuracy is key.
Good luck.
Thread Starter
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From: Newfoundland
BTW if the mechanic had no idea what those codes meant, hire a new mechanic.
Low voltage on the BCM can be bad battery, charging system fault, or the PCM is going bad.
I always check batt voltage first and look for the voltage jump (alternator working) when you start the truck. If those are within normal range, it's the PCM.
My previous comment, I was assuming battery and alternator were already checked. Thats mechanic 101 stuff for low voltage error.
Low voltage on the BCM can be bad battery, charging system fault, or the PCM is going bad.
I always check batt voltage first and look for the voltage jump (alternator working) when you start the truck. If those are within normal range, it's the PCM.
My previous comment, I was assuming battery and alternator were already checked. Thats mechanic 101 stuff for low voltage error.
had him check the battery and alternator and both are working fine so I’m assuming it’s the PCM
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Thread Starter
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From: Newfoundland