Common Problems on the 2002-2006 Chevy Avalanche

Common first-generation Chevy Avalanche problems include a tailgate that won’t latch, a tailgate with a broken handle that won’t open, or faded plastic panels that need restoration. All vehicles have their common problems, so our experts went over the top problems owners experience with the Chevy Avalanche, some of their causes, and how to fix them.

Common Issues with the 1st Gen Chevy Avalanche (2002-2006)

1. Faded Trim

Symptoms of Faded Plastic/Trim

• Plastic trim on the sides, the bumpers, and the bed are faded, which can happen over time

How to Fix Faded Plastic/Trim

• Heating the plastic trim with a heat gun will warm up the plastic and eliminate fading, but this option is time-consuming
• For a faster process, apply trim restoration to the plastic for about 5 minutes. Wipe the restoration off with a microfiber towel.

2. Fuel Trim Codes

Signs the Avalanche Has a Fuel Trim Code

• Check engine light comes on for a fuel trim code like P0101, but it usually appears for a lean code like P0171 or P0174
• Possible engine misfire or engine vibration

Causes of Fuel Trim Codes

The engine needs an air/fuel mixture of 14.7:1 for the best engine performance and fuel mileage. The mass air flow (MAF) sensor and oxygen (O2) sensors measure this ratio. If air manages to get into the intake and pass the MAF sensor without a reading, it will throw the ratio off and trigger a check engine light.

Parts that Can Cause a Fuel Trim Code

• Loose or broken air intake tube
• Broken intake gaskets underneath the air intake manifold
• Faulty or dirty MAF sensor
• Faulty O2 sensor

How to Fix Fuel Trim Codes

• Secure the air intake tube or replace it if it is broken
• Replace broken intake gaskets
• Clean a dirty MAF sensor or replace a faulty MAF sensor
• Replace a faulty O2 sensor

3. Defective Front Impact Sensors

Symptoms of Bad Front Impact Sensors

• Air bag light is on and codes in air bag module are for front impact sensors—B0102 and B0103

Causes of Bad Front Impact Sensors

The impact sensors are attached to the front of the frame/lower radiator support. Sometimes the wires can tear or an electrical connector can corrode, but usually the impact sensors corrode.

How to Fix Bad Front Impact Sensors

Replace the impact sensor if it is defective. We recommend replacing the impact sensors in pairs. Steps include disconnecting the battery, removing the 10mm bolt from the bottom of the sensor, and sliding it out of the truck.

4. Encoder Motor Problems

Symptoms of a Bad Encoder Motor

• Check engine light is on for code C0327, meaning the computer cannot locate the encoder motor
• Four-wheel drive (4WD) module will read for a code and 4WD won’t engage

How to Fix a Encoder Motor Problems on the 02-06 Chevy Avalanche

• You can replace the sensor or the entire motor. It is cheaper to replace the sensor and it is not a difficult repair.
• Remove the motor, pull it apart, and if the motor is not corroded the sensor can be replaced

5. Defective EVAP Vent Valve, aka Vapor Canister Vent Valve

Symptoms of a Bad EVAP Vent Valve

• Check engine light is on for codes P0449, P0455, P0446

Causes of a Bad EVAP Vent Valve

• The vapor canister vent valve or EVAP vent valve is located next to the fuel tank. It is part of the evaporative emissions control (EVAP) system and vents fresh air into it. If there’s too much pressure, it opens the vent. Normally it is open until it is activated to close, which puts a vacuum on the system to keep vapors out of the atmosphere. A defective EVAP vent valve likely won’t affect driveability, but it will keep the truck from passing an emissions test at inspection.
• A faulty gas cap or gas cap seal can cause a non-circuit EVAP system check engine light

How to Fix a Bad EVAP Vent Valve

• For circuit codes, inspect the electrical connectors for discoloring or corrosion. Test the connector for power and ground with a test light. Chances are it’s the electrical connector.
• If the electrical connection is fine, replace the EVAP vent valves. Newer replaceable vent valves for the 02-08 Chevy Avalanche may look different but work just the same.
• If the check engine light is on for an EVAP code but not a circuit code, make sure the gas cap is secured tightly and does not have a broken seal. If it has trouble tightening or has a broken gas cap seal, replace it.

6. Broken Tailgate Handle

Symptoms of a Broken Tailgate Handle

• Tailgate won’t latch or unlatch easily

Causes of a Broken Tailgate Handle on the 02-08 Chevy Avalanche

The tailgate handle tends to rust, keeping the tailgate handle rods from releasing and closing the tailgate

How to Fix a Broken Tailgate Handle

1. Remove the five bolts from the bed trim panel behind the tailgate
2. Remove the trim surrounding the tailgate handle
3. Disconnect the rods from the tailgate handle
4. Reverse the procedure to reinstall

Replace 02-06 Chevy Avalanche Parts Yourself

To replace parts yourself, check out 1A Auto’s how-to videos, which cover many years, makes, and models, including the 2002-2006 Chevy Avalanche.

Shop 02-06 Chevy Avalanche Parts Mentioned in This Article

• Intake Manifold Gaskets
• MAF sensor
• O2 sensor
• EVAP Vent Valve

Related Content

• Gas Cap Throwing a Check Engine Light? [Diagnose & Fix]
• Can a Bad O2 Sensor Cause a Misfire?
• MAP vs. MAF vs. IAT Sensors

1st Generation Chevrolet Avalanche Model Years

• 2002 Chevy Avalanche 1500, 2500
• 2003 Chevy Avalanche 1500, 2500
• 2004 Chevy Avalanche 1500, 2500
• 2005 Chevy Avalanche 1500, 2500
• 2006 Chevy Avalanche 1500, 2500