Wife's TB went into reduced power mode , and threw codes P0300 , C0244 .
Found TSB that says the P0300 is number 4 cylinder miss fire , caused by water in boot area , does the C0244 come from the reduced power as well ?

 

P0304 is cy #4. P0300 is not cylinder specific. P0300 is random misfires which can't be pinpointed to any specific cylinder thus they're called random.

 

Correct , P0300 is generic and covers more than one fault , but the TSB states the exact cause if
thrown , just passing on a TSB info .
You mean like this ?

Readers of the On Board Diagnostics will know that the DTC consists of a single letter and four numbers. What they might not realize is that the code is not simply a sequential number from a list, but a code with its own meaning that relates to the concern to which it refers.

We will take the first OBDII code as an example, P0100 MAF circuit malfunction.

The DTC can be disassembled as follows:
Prefix 1st 2nd 3 & 4th
P

0
1 0 0



PREFIX:

B - Body
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C - Chassis
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P - Powertrain
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U - Network

1st

The first number is not a zero value or a 1000 number - it is a code of 0 or 1.
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0 - If the code has the first numerical digit of 0 then the code is a generic - that is, standard, OBD code which will refer to every vehicle.
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1 - if the first digit is 1 then the code is described by the manufacturer and care must be taken to use the correct set of manufacturer PCM-specific OBD codes, or the results may be misleading. Our codes must be specific to the EECV powertrain control module (PCM)

2nd

The second number contains even more useful information - it shows what area of PCM operation the code refers to. These are
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1 - Fuel & Air Metering
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2 - Fuel & Air Metering - Injectors only
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3 - Ignition System or Misfire Monitor
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4 - Auxillary Emission Control System (Meaning EGR, Catalyst & EVAP systems)
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5 - Vehicle Speed Control and Engine Idle Control
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6 - Computer Output Circuits
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7 - Transmission
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9 - Transmission

3 & 4th

The last two numbers identifies the actual fault.

So by looking at the very first code P0100, before we even reach for a list we know that it is a Powertrain code which is OBD generic and that the code is related to the Fuel & Air Metering - which is exactly what the MAF does.


TSB #: 060604048 NHTSA#: 10020879
Does this help ?

 

That's a new one on me. Never seen P0300 point to a specific cylinder. It's always been P0301 to 308 if it could be narrowed down to a specific cylinder. I'll look up that TSB. If it is cy. #4 why doesn't it just set DTC P0304 as you would expect?

 

Who knows , I agree it should be 304 (maybe just generic TSB number any P0xxx code) , I have heard of this TSB before just was hoping it did not happen to ours .
Seems water gets down around the number 4 and causes corrosion .