Check engine light causes

[KyRob]

My o4 sierra's check engine light came on a couple days ago at startup. Truck has 56,000 miles on it. What would be most likely cause of this? I checked intake filter and it looks clean. Haven't changed gas brand or anything. Can autozone do a check on it and see what it is or is this a dealership deal?

 

Thanks,

[ujtruck]

1st autozone then Dealership deal, keep your credit card handy

[KyRob]

Autozone code was 0442. Any idea what this is?

 

Thanks,

[Duelin]

P0442 2004 GMC SIERRA 1500 V6 4.3

 

EVAP System Small Leak Detected

– The control module detects approximately 6 vacuum/pressure changes significantly less than a calibrated amount

 

Probable Cause

 

1. Loose or missing fuel filler cap

2. Loose or damaged EVAP hose

3. Faulty Purge Solenoid

4. Faulty vent solenoid

5. Faulty EVAP purge switch

 

P0442 2004 GMC SIERRA 1500 V8 4.8

 

EVAP System Small Leak Detected

– The control module detects approximately 6 vacuum/pressure changes significantly less than a calibrated amount

 

Probable Cause

 

1. Loose or missing fuel filler cap

2. Loose or damaged EVAP hose

3. Faulty Purge Solenoid

4. Faulty vent solenoid

5. Faulty EVAP purge switch

 

P0442 2004 GMC SIERRA 1500 V8 5.3

 

EVAP System Small Leak Detected

– The control module detects approximately 6 vacuum/pressure changes significantly less than a calibrated amount

 

Probable Cause

 

1. Loose or missing fuel filler cap

2. Loose or damaged EVAP hose

3. Faulty Purge Solenoid

4. Faulty vent solenoid

5. Faulty EVAP purge switch

 

P0442 2004 GMC SIERRA 1500 V8 5.3

 

EVAP System Small Leak Detected

– The control module detects approximately 6 vacuum/pressure changes significantly less than a calibrated amount

 

Probable Cause

 

1. Loose or missing fuel filler cap

2. Loose or damaged EVAP hose

3. Faulty Purge Solenoid

4. Faulty vent solenoid

5. Faulty EVAP purge switch

[KyRob]

Thanks for the info Duelin, I appreciate it.

 

Rob

[SILVERADOSC540]

Check number 1 on all of Duelin's list. Had a co-worker with check engine light, went to an independent who wanted $$$$ to change out a sensor, took it to the dealership and they tightened up his gas cap...