02 Chevy blazer p0155,p0446 codes. What to do?

Evap. emission vent valve problem , maybe !
Chevy Truck Hard To Fill Gas Tank GM EVAP Codes P0442 P0446 P0455 or P0449...
Fixing Car Where The Gas Pump Keeps Shutting Off As You Try To Refuel

Here's a link for codes P0446,P0443. https://www.obd-codes.com/p0446 Here's the link for P0403. P0403 Exhaust gas recirculation EGR circuit malfunction Here's code P0135 P0135 OBD II Trouble Code O2 Sensor Heater Circuit Malfunction Bank 1... Here's code P0141 P0141 OBD II Trouble Code O2 Sensor Heater Circuit Malfunction Bank 1... Here's code P0155. P0155 OBD II Trouble Code 02 Sensor Heater Circuit Malfunction Bank 2... Here's the last code.yay P0161. P0161 OBD II Trouble Code HO2S Heater Circuit Malfunction Bank 2 Sensor 2... The last 3 codes might just be one sensor.

P0155 O2 Sensor Heater Circuit Malfunction (B2S1)
bank 2 ...side one

either the 02 sensor has failed or getting too much voltage

go with replace 02 sensor first

YOU REPLACED PARTS FOR NOTHING ! P0446 Chevrolet Evaporative Emission Vent System Performance Chevy Impala Check Engine Light Codes P0446 P0451 EVAP Trouble HERE WATCH A REAL TECH.

TYPE: OBD & your codes

OBD PO440

OBD PO302

etc & do some studying (learning)

P0446 Evaporative Emmission Control System Vent Control Circuit

Evap vent valve has only one purpose. It closes in order to seal the vent so the EVAP system can pressurize and ensure there are no leaks.

This code could mean one or more of these issues have happened:

Faulty vent valve
Open, short or excessive resistance on Vent valve control circuit

Blockage of vent valve

Bad PCM

Here are some things you can try:

Replace Vent valve

Repair open, short, or resistance problem in control circuit

Repair open, or short, or resistance problem in power circuit

Replace PCM

p0155 is an oxygen sensor code. ( 02 sensor bank 2 sensor 1 ). I believe bank two is the one for cylinders 2, 4, and 6. Sensor 1 would be the first one that is closest to the beginning of the exhaust manifold. hope this helps and have a good day ! on passengers side of engine. go to any auto parts store to purchase the sensor.

P0446 = Evaporative Emission Control / System Vent Control Circuit Malfunction.

Check it, and before you replace the Evap Canister read this:

Subject: DTC P0446 (Restricted/Blocked EVAP Vent Path) Set, Service Engine Soon (SES) Lamp Illuminated (Replace Hose/Evaporative Emission (EVAP) Canister Vent Asm) #02-06-04-037A - (02/02/2005)
Models: 1999-2003 Chevrolet Silverado Models
1999-2003 GMC Sierra Models
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This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 02-06-04-037 (Section 06 -- Engine/Propulsion System).
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Condition
Some customers whose vehicles are operated in dusty type environments, such as farming or mining off-road type applications, may comment about the illumination of the instrument panel SES light, with a DTC of P0446 (Restricted/Blocked EVAP Vent Path) being set.

Cause
Dirt and dust intrusion into the EVAP canister vent hose assembly, resulting in restricted air flow, may cause this condition.

Correction
After following the Service Manual diagnostic P0446 and determining that the EVAP canister vent valve is the cause of the SES light, replace the existing EVAP canister vent hose assembly with a new assembly, P/N 15086429. This new assembly has an enhanced filtering capability and a filter element that can be easily removed and cleaned. To ensure correct installation, follow the procedure below.

Raise the vehicle. Suitably support the vehicle.
Disconnect the EVAP canister vent valve electrical connector.
Disconnect the vent valve pipe at the EVAP canister.
Remove and retain the EVAP canister vent valve bracket mounting bolt.
Disengage, from the underbody, the two vent valve pipe clips securing the pipe to the underbody.
Remove and discard the complete EVAP canister vent hose assembly.
Position and secure the new assembly to the underbody using the existing hole and mounting bolt.
Tighten
Tighten the bracket mounting bolt to 12 N·m (106 lb in).

Install the two vent valve pipe clips into the existing underbody holes.
Connect the vent valve pipe to the EVAP canister.
Connect the EVAP canister vent valve electrical connector.
Lower the vehicle.
When properly installed, the new EVAP canister vent hose assembly will be positioned outboard of the original installation location. This new location provides clearance for accessing the filter element for cleaning purposes. To access the filter element, disengage the filter cover to valve locking finger by gently lifting the finger upward while simultaneously rotating the filter body clockwise. After approximately 45 degrees of rotation, the filter can be disengaged from the valve by gently pulling outward. The filter cover can then be removed and the filter element and body can be washed with soap and water. Prior to reinstalling, ensure that the body and filter element are dry.

Parts Information
Part Number 15086429 Hose Asm-Evap Emis Cnstr Vent

Hope help with this.

P0155 is o2 sensor heater circuit malfunction bank 2 sensor 1 it is the o2 sensor circuit in front of the cat converter the o2 sensors are located mounted to the exhaust pipe in front and behind the catylic converter the problem is in the circuit [wiring or sensor itself] check wiring and repair if necessary if the short or open circuit is the sensor need to replace sensor +++ P0161 is 02 sensor heater circuit malfunction BANK 2 SENSOR 2 ++++++ this is the sensor behind the cat converter

P0155 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)
THIS IS THE SENSOR BEFORE THE CAT CONVERTER
P0154 02 Sensor Circuit No Activity Detected (Bank 2 Sensor 1)
SAME SENSOR, WHEN THEY SAY BANK 2 IT IS THE BANK OF CYLINDERS OPPOSITE THE BANK THAT HAS #1 CYLINDER IN IT,
MAKE SURE THE SENSOR IS CONNECTED AND THAT THE CONNECTOR IS NOT DAMAGED.