What does PO 741 and PO 894 codes mean? - 2005 GMC Sierra C/K3500

Hi, I know from my past experiances the spark plug wires at the boot ends than slide onto the sparkplugs usually over time short out due to the metal tubes that protect the sparkplugs from heat kind of ark across from the metal tube through the plug boot causing an error code. Sometimes in the dark you can actually see them arking at the tube on the engine, and also hear a crackling noise. As to the code for the O2 sensor that's a normal wear and tear item that may need replaced. As all vehicle age over time electrical connections, and things have issues develop and cause havick with sensors and computers in these vehicles too.


As with the 441 code and then the other code for the O2 sensor showing up may mean both O2 sensors are going bad if your system has 2 sensors in the exhaust, usually one before the cat converter and one behind it. A lot of this also is due to what gasoline you use in the vehicle over time. Lower octane gas may be what is causing things to act up.

what engine, what size. that is first question.
misfire, map ,maf, iat, ect,tps and cat fail and low coolant temps.
very odd mix there. did you pull connections, key on???????

it means they all fail a test.
DIY? or just curious?

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the question is , which is the most important.
all are cept 420, (last that, and bet goes way. later.)

reset the ECU, and see which come back.?
check all fuses.
then post codes that repeat, after fuse checks.

does the engine get fully hot running, 180F minimum?

Take it to a qualified repair shop an have it diagnosed properly !

These codes are making me lean towards the ignition coil pack.My stepson's 2001 Sable 3.0 v6 had one cylinder misfiring(5-code P0305),which shares a coil with cylinder 1(code P0301).I diagnosed it by trading wire 1 and 5 at the coil,and the code changed to P0301.You have codes for the two cylinders on the same coil,so this is most likely it.(these codes would also trigger P0300(Multiple Misfires Detected) and P0316(Misfire Detected First 1000 Revs)).

this obd2 trouble code table can help you understand the meaning of code.
and for your code, I think you can try to change the whole sending unit with the fuel pump in the tank. And see if the code come back.

171 and 174 mean not enough fuel po 300 multiple missfire could be not enough fuel 430 can be caused by bad ignition in the cat from not enough fuel // first thing borrow a freinds mass airflow sensor

P174 means Oxygen sensor was slow in switching Single, Right or Rear HO2S - Fuel control

P171 means Oxygen sensor not switching - system was at adaptive limits - Single, Right or Rear HO2S - Fuel control

Visit http://www.troublecodes.net/Ford/
for a comprehensive code listing for your car.

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P0154 HO2S-11 (Bank 1 Sensor 1) No Activity Detected
P0174 Fuel System Lean (Bank 2)

It sounds like the convertor in the exhaust system is partly blocked. You will need to have this checked at a shop. Frankster016

P0700 - Transmission Control System Malfunction, this is a transmission or PCM issue and needs further diagnosis with other test gear.

The P1684 code simply means that the battery has been disconneted within the last 50 engine starts.