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2013 Sierra 1500 PO420 Code

ChevyTuff
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KirkA Enthusiast

KirkA

Posted
Posted
On 2/23/2021 at 5:01 PM, ChevyTuff said:

What's a good way to check for leaks ..... Stethoscope or maybe a hose?

Attach a shop vac to the exhaust pipe (duct tape) and put pressure into the pipes.  Spray soapy water at every joint.  If it bubbles up, have found your leak.

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tbarn
tbarn

99.9% of  the time P0420/30 is a bad cat. You're making it more expensive and harder than it needs to be.

CamGTP
CamGTP

P0420 is the drivers side cat, P0430 is the passenger side cat.   P0135 is a circuit code on the bank 1 sensor 1 o2 sensor, that being the drivers side. Could be a bad new sensor. I only run

CamGTP
CamGTP

OEM means AC Delco or Denso parts, not anything else.   I have part numbers of Denso 2344668 or possibly 2133866. Most auto parts stores carry them as well.    

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swathdiver Senior Enthusiast

swathdiver

Posted
Posted
On 2/16/2021 at 8:43 AM, ChevyTuff said:

My truck has new Oxygen Sensors on it (All 4) and is still throwing this code.

Trust your instruments, get new cats before they take out your motor.  Penny wise or pound foolish.

 

My cat temps are in the 700s+ at idle with a warmed up motor according to the Tech-2.

 

Magnaflow 51578, got a great deal from GotExhaust back in 2018 for my truck.

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ChevyTuff Enthusiast

ChevyTuff

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Posted

OK, got my new thermometer today and measured the temps on driver side Cat at Front - 421*  Rear - 437*

swathdiver Senior Enthusiast

swathdiver

Posted
Posted
On 2/28/2021 at 6:21 PM, ChevyTuff said:

You guys are right. I ordered the new Y Pipe today.

Good, keep us posted.  

bg1988 Enthusiast

bg1988

Posted
Posted (edited)
On 2/23/2021 at 3:29 PM, tbarn said:

99.9% of  the time P0420/30 is a bad cat. You're making it more expensive and harder than it needs to be.

 a fuel trim read of 34  or if it is above 550C  (1000f+)  will set a catalyst  code

Edited by bg1988
ChevyTuff Enthusiast

ChevyTuff

Posted
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Posted

I have a Cat Y pipe ordered. I don't know why it takes 2 or 3 weeks to get it. Must be coming across the pond on a rubber raft from China.

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ChevyTuff Enthusiast

ChevyTuff

Posted
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Posted

OK Guys, Here's an update. I had the new Y Pipe installed, and now I'm getting a P0030 Code. My engine is still Mis-Firing after I drive to town, shut it off, and go in a store. When I come back out of the store and start it up, it misses for about a block, then straightens back up. I have replaced all 4 O2 sensors with OEM Sensors. 

This is really starting to get to me. Could this be a probelm with the Body Control Module or possibly Engine Control Module?

IMG_1996.jpg

CamGTP Senior Enthusiast

CamGTP

Posted
Posted

I would swap front o2 sensors side to side, if the issue follows then it's the new sensor that is bad.

 

If it stays the same then it's a wiring issue.

ChevyTuff Enthusiast

ChevyTuff

Posted
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Posted (edited)

I mentioned all my other electrical problems to a friend tat is pretty sharp on GM trucks. These are other issues I am having right now:

1. Cannot set clock on radio. Other radio buttons don't work such as some favorites buttons.

2. Driver's door does not turn on courtesy light, radio plays for 20 minutes after exiting.

3. Cannot get one of my parking assist sensors to work, brand new. Service parking assist displays on dash and I have to scroll out of it every time I drive the truck.

4. Driver's window does not work part time.

5. Oil pressure gauge stopped working.

6. Truck misses and runs poorly after warmed up, then parked for 10 minutes, and re-started.

Any way, he said it sounds like a bad body control module.. Could this be causing that issue?

I will try swapping the two rear 02 Sensors.

I have a brand new OEM Body Control Module to install, but have not put it in yet.

 

Edited by ChevyTuff
swathdiver Senior Enthusiast

swathdiver

Posted
Posted
1 hour ago, ChevyTuff said:

I mentioned all my other electrical problems to a friend tat is pretty sharp on GM trucks. These are other issues I am having right now:

1. Cannot set clock on radio. Other radio buttons don't work such as some favorites buttons.

2. Driver's door does not turn on courtesy light, radio plays for 20 minutes after exiting.

3. Cannot get one of my parking assist sensors to work, brand new. Service parking assist displays on dash and I have to scroll out of it every time I drive the truck.

4., Driver's window does not work part time.

5. Truck misses and runs poorly after warmed up, then parked for 10 minutes, and re-started.

Any way, he said it sounds like a bad body control module.. Could this be causing that issue?

I will try swapping the two rear 02 Sensors.

I have a brand new OEM Body Control Module to install, but have not put it in yet.

 

Some issues may be related to a bad BCM while others, like the O2 sensor code is related solely to the ECM.  Then again, the radio itself may need some work too.  A bad cell in a good battery will do ALL of this too.  Same with bad battery cables and the various grounds throughout the truck.

 

You really need a Tech-2 and a subscription to ALLDATADIY to access the shop manual.  From the shop manual:

 

CONDITIONS FOR SETTING THE DTC
P0030 or P0036
 The ECM detects that the affected HO2S heater low control circuit is not within a specified range.
 DTCs P0030 and P0036 set within 3 seconds when the above condition is met.

 

CIRCUIT/SYSTEM VERIFICATION
 Allow the engine to reach operating temperature. With the engine running, observe the HO2S Heater
parameter with a scan tool. The value should vary from between 0.5-2A.
 Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You
may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure
Records data.

 

CIRCUIT/SYSTEM TESTING

1. Ignition OFF, disconnect the harness connector at the appropriate HO2S.
2. Ignition ON, verify that a test lamp illuminates between the appropriate HO2S heater voltage supply
circuit terminal D and ground.
 If the test lamp does not illuminate, test the HO2S heater voltage supply circuit for a short to
ground or an open/high resistance. If the circuit tests normal and the HO2S heater voltage supply
circuit fuse is open, test all components connected to the fuse and replace as necessary.
3. Ignition ON, verify that a test lamp does not illuminate between the appropriate HO2S heater voltage
supply circuit terminal D and the appropriate HO2S heater low control circuit terminal C.
 If the lamp illuminates, test the HO2S heater low control circuit for a short to ground. If the circuit
tests normal, replace the ECM.
4. Engine running, leave the test lamp connected from the previous step. The lamp should flash or be ON
steady.
 If the test lamp is not ON steady or flashing, test the HO2S heater low control circuit for a short to
voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

 

IMPORTANT:  The output driver should detect a short to voltage and turn OFF. If a
resistance fault is present the driver will remain ON and the scan
tool will display more than 0.0 amp. Less than 10 ohms of resistance
may set a DTC.
 Performing this test may set additional DTCs.


5. Ignition OFF, install a 30A fused jumper wire between the appropriate HO2S heater voltage supply
circuit terminal D and the appropriate HO2S heater low control circuit terminal C.
6. Engine running, verify the appropriate scan tool HO2S Heater parameter is less than 0.1 amp.
 If more than the specified range, test the HO2S heater voltage supply and HO2S heater low control
circuits for more than 1 ohm of resistance. If the circuits test normal, replace the ECM.
7. If the ECM and all circuits test normal, replace the appropriate HO2S.

 

ChevyTuff Enthusiast

ChevyTuff

Posted
  • Author
Posted (edited)

I installed a new battery just a couple of weeks ago at Walmart. The PO420 code was coming on before that though.

Wow, this sounds like a bit more than I am capable of doing because I don't know how to do anything with my scan tool except erase codes. Maybe I should just take my truck to a dealer and have them put it on the scope at $125.00 an hour. I forgot to mention, my oil pressure gauge quit working also. 

Since I have the BCM, maybe I should go ahead and replace it. I was told that after install, I just need to turn the key on and let it learn the key code. Is this correct?

Edited by ChevyTuff
swathdiver Senior Enthusiast

swathdiver

Posted
Posted
16 hours ago, ChevyTuff said:

I installed a new battery just a couple of weeks ago at Walmart. The PO420 code was coming on before that though.

Wow, this sounds like a bit more than I am capable of doing because I don't know how to do anything with my scan tool except erase codes. Maybe I should just take my truck to a dealer and have them put it on the scope at $125.00 an hour. I forgot to mention, my oil pressure gauge quit working also. 

Since I have the BCM, maybe I should go ahead and replace it. I was told that after install, I just need to turn the key on and let it learn the key code. Is this correct?

Like I said, a new battery can have a bad cell and wreak havoc on an electrical system.  It ought to be properly tested.

 

The BCM has to be programmed to your vehicle and VIN so all of your options work.  The most important tool for working on these trucks is a Tech-2, if you plan on keeping this I suggest you buy one and in your case it will pay for itself just in solving these mysteries you're having and in programming the BCM to your VIN.  The dealer will cost a few bucks but at least you'll get some problems solved and others you can fix yourself once they diagnose them for you.

ChevyTuff Enthusiast

ChevyTuff

Posted
  • Author
Posted (edited)

Swap the Front, not the Rear sensors? Also, on the battery, I was getting the PO420 code before I changed the battery, but I'll have this new one checked.

Edited by ChevyTuff

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