02 Yukon Denali PO420 Code

[Rocket Man]

Well, I took a chance and cleaned the MAF and new air filter... and so far (80 miles) no codes... I was getting them every 30 miles or so, maybe that did it? I'll update in a few more miles.... A friend suggested it might be that and/or loose conncections at the MAF, so I tighened and cleaned everything.... so far so good, I'll see... $350 to replace CAT.

Ummmmm....no. Lol.

 

[malmed]

Been driving her to and from work all week... 28 miles a day, 5 days, no CEL.
I will update if it changes, but so far, that appears to have "fixed" it.

 

[Vetkllr]

Been driving her to and from work all week... 28 miles a day, 5 days, no CEL.
I will update if it changes, but so far, that appears to have "fixed" it.

Any updates? I am having the same issue as well. I started off with a bunch of codes they were as follows;

P0137 HO2S Circuit low voltage Bank 1 Sensor 2 DTC Severity 2 of 3 Repair immediately if drivability issues.
P0101 Mass Air Flow (MAF) Sensor Performance.
P0332 Knock Sensor 2 Circuit Low Voltage Bank 2
P1516 Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance

First I decided to replace the whole throttle body. While I replaced it I unhooked the battery so that would clear the codes. After the repair. The check engine came back on and threw a code of
P0140 HO2S Circuit Insufficient Activity Bank 1 Sensor 2

so at this point I am thinking about replacing the driver side sensor after the cat. But I might try switching the sensors to see what happens. Any suggestions out there? I’m all ears.

 

[malmed]

I am another week and 300+ more miles with no Check Engine light. It appears cleaning the MAF and new air filter made MY P0420 code go away...

 

[afpj]

Get a Lotto ticket

 

[malmed]

Went on vacation, after couple hundred miles, came back and acting the same as before, can hardly make 30 miles before CEL again.... so, no joy....