New Kon owner. Lots of codes | problems...

[nimrod.sixty9]

Just bought a 1999 Yukon 5.7 with with a few issues. Runs fairly well, when cruising on the highway it runs great. At idle cold or hot, I can feel a bit of a miss.

Before getting the truck home I stopped at Advance to check the codes:
B0225
B0227
B0235
B0226
All the B codes had to do with LF Speed Sensor and Rear Speed Sensor (did not specify pass or driver)

P0141 - HO2S Heater Performance Bank 1 Sensor 2
P0155 - HO2S Heater Performance Bank 2 Sensor 1
P0161 - HO2S Heater Performance Bank 2 Sensor 2
P0304 - Cyl #4 Missfire

Im thinking whats causing cyl 4 missfire is causing the O2 codes. Would I be right? Where would you start in all this mess?

 

[_Dylan_]

Just bought a 1999 Yukon 5.7 with with a few issues. Runs fairly well, when cruising on the highway it runs great. At idle cold or hot, I can feel a bit of a miss.

Before getting the truck home I stopped at Advance to check the codes:
B0225
B0227
B0235
B0226
All the B codes had to do with LF Speed Sensor and Rear Speed Sensor (did not specify pass or driver)

P0141 - HO2S Heater Performance Bank 1 Sensor 2
P0155 - HO2S Heater Performance Bank 2 Sensor 1
P0161 - HO2S Heater Performance Bank 2 Sensor 2
P0304 - Cyl #4 Missfire

Im thinking whats causing cyl 4 missfire is causing the O2 codes. Would I be right? Where would you start in all this mess?

C0225-LF wheel speed sensor circuit open
C0227-LF wheel speed sensor circuit erratic
C0235-rear speed signal circuit open or grounded
C0226-LF wheel speed sensor signal missing

I'd start with the wheel speed sensors they might just be unplugged. The rear sensor is on the transmission(2wd) or the transfercase (4wd).

 

[electro]

The one on the transfer case is called Vehicle Speed Sensor? Among other things output signal runs your speedo.

I know nothing of the heater bank stuff.

Good luck!

 

[SunlitComet]

bank 1 left cylinder head. 2 right cylinder head. sensor 1 before cats. sensor 2 after cats. and yes on the VSS but does not run it directly.

 

[nimrod.sixty9]

Which is left and which is right? Is it from driver seat or facing from front?

Need to also know this for the ABS speed sensor.

EDIT:

Err Google... Looks like from driver seat so the pre CAT O2 would match up with Cyl 4 side.

Just bought Cap and rotor; hope this helps cause this damned thing was expensive!

 

[nimrod.sixty9]

Inspected the plug in cyl #4 and noticed a very small crack on what I believe to be called the electrode (had another laying around). Also decided to check the gap and sure enough, no more than .035. Checked the rest of the plugs and low and behold all were incorrectly gapped. Regapped and no more rough idle or missing!

ABS light is also now off. Replaced the left front speed sensor with one I pulled from a JYard today. Never messed with anything on the rear.

Just drove the hell out of it; NO CODES AT ALL!

Still have an issue with the peddle pressure though. Goes to the floor but still seems to stop fairly well. Have to let into it fairly slow otherwise harder to push and less effective. Im thinking brake booster. Not really sure where to start troubleshooting. Thoughts, input, advice?

 

[_Dylan_]

The cracked plug can cause the spark to ground to the block resulting in a misfire.

Good job finding the fix.

 

[nimrod.sixty9]

Thanks! Im going to try cleaning out the drums today and then try the reverse auto adjusting trick. Hopefully that will help.

 

[fire730]

Inspected the plug in cyl #4 and noticed a very small crack on what I believe to be called the electrode (had another laying around). Also decided to check the gap and sure enough, no more than .035. Checked the rest of the plugs and low and behold all were incorrectly gapped. Regapped and no more rough idle or missing!

ABS light is also now off. Replaced the left front speed sensor with one I pulled from a JYard today. Never messed with anything on the rear.

Just drove the hell out of it; NO CODES AT ALL!

Still have an issue with the peddle pressure though. Goes to the floor but still seems to stop fairly well. Have to let into it fairly slow otherwise harder to push and less effective. Im thinking brake booster. Not really sure where to start troubleshooting. Thoughts, input, advice?

Congrats on fixing the misfire.

Plus the lesson you may or may not have learned with buying the cap and rotor. You will spend a fortune just throwing parts at your truck to fix it.

And the brake issue isnt going to be the booster. A failed booster will cause a hard pedal. A soft or spongy pedal will be a pressure issue or a misadjusted rear drum, stuck front caliper slide, bad master cylinder, leaking rear wheel cylinders, or could be other things.

Not trying to preach - Just trying to help.

 

[crxx]

some steel braided brake lines are a great upgrade for the brake system once you get new brakes on it and make sure the wheel cylinders arent leaking and everything else checks out as well. good luck with her!