Silverado 2008

5.3L V8 VIN M Auto 16

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Trouble Code: P0420



Catalyst System Low Efficiency (Bank 1)

Possible Causes:



Air leaks at the exhaust manifold or in the exhaust pipes
 
Base engine problems (i.e., high engine oil or coolant usage)
 
Catalytic converter is damaged, contaminated or has failed
 
Continuous engine misfire conditions, or weak or low coil output
 
Front HO2S or rear HO2S is contaminated with fuel or moisture
 
Rear HO2S is loose in the mounting hole (check it for a leak)
 
TSB 81-65-37 contains a repair procedure for this code
 

Trouble Code: P0430



Catalyst System Low Efficiency (Bank 2)

Possible Causes:



Air leaks at the exhaust manifold or in the exhaust pipes
 
Base engine problems (i.e., high engine oil or coolant usage)
 
Catalytic converter is damaged, contaminated or has failed
 
Continuous engine misfire conditions, or weak or low coil output
 
Front HO2S or rear HO2S is contaminated with fuel or moisture
 
Rear HO2S is loose in the mounting hole (check it for a leak)
 

Trouble Code: P0442



EVAP System Small Leak (0.040") Detected

Possible Causes:



Charcoal canister is loaded with fuel or moisture
 
Fuel filler cap is loose, cross-threaded, damaged or wrong part
 
Fuel tank, fuel filler neck or fuel sending unit 'O' ring is leaking
 
Fuel tank pressure sensor is damaged, disconnected or it failed
 
Fuel tank vapor line(s) is clogged, damaged or disconnected
 
Purge valve vapor line is clogged, damaged, or disconnected
 
Purge solenoid or Vent solenoid has a small leaking (sticking)
 
ECM has failed
 

Trouble Code: P0442



Evaporative Emission (EVAP) System Small Leak Detected

Possible Causes:



Damaged EVAP purge solenoid
 
Damaged EVAP vent valve or EVAP canister
 
Incorrectly routed, kinked, or damaged EVAP pipes and hoses
 

Trouble Code: P0442



Evaporative Emission (EVAP) Purge Solenoid Control Circuit

Possible Causes:



EVAP canister purge or vent solenoid valve voltage supply circuit for a short to ground or an open/high resistance
 
EVAP canister purge or vent solenoid valve control circuit for a short to ground
 
EVAP canister purge or vent solenoid valve control circuit for a short to voltage or an open/high resistance
 
EVAP canister purge or vent solenoid valve
 
ECM has failed
 

Trouble Code: P0443



EVAP Purge Solenoid Control Circuit Malfunction

Possible Causes:



Purge solenoid control circuit is open or shorted to ground
 
Purge solenoid control circuit is shorted to system power (B+)
 
Purge solenoid power circuit is open (test the ENG1 fuse)
 
Purge solenoid is damaged or has failed
 
ECM has failed
 

Trouble Code: P0446



EVAP Vent System Performance

Possible Causes:



EVAP vent fresh air hose is clogged, kinked or restricted
 
EVAP Vent solenoid is contaminated, damaged or has failed
 
EVAP Canister plugged or severely restricted
 
Fuel Cap or EVAP Service Port leaking
 
Fuel vapor lines or purge lines damaged or leaking
 
FTP sensor is out-of-calibration, damaged or "skewed"
 
ECM has failed
 
TSB 02-06-04-037 contains a repair procedure for this code
 

Trouble Code: P0446



Evaporative Emission (EVAP) Vent Solenoid Control Circuit

Possible Causes:



EVAP canister purge or vent solenoid valve voltage supply circuit for a short to ground or an open/high resistance
 
EVAP canister purge or vent solenoid valve control circuit for a short to ground
 
EVAP canister purge or vent solenoid valve control circuit for a short to voltage or an open/high resistance
 
EVAP canister purge or vent solenoid valve
 
ECM has failed
 

Trouble Code: P0449



EVAP Vent Solenoid Control Circuit Malfunction

Possible Causes:



Vent solenoid control circuit is open or shorted to ground
 
Vent solenoid control circuit is shorted to system power (B+)
 
Vent solenoid power circuit is open (test the ENG1 fuse)
 
Vent solenoid is damaged or has failed
 
ECM has failed
 

Trouble Code: P0449



Fuel Tank Pressure (FTP) Sensor Circuit

Possible Causes:



EVAP purge solenoid valve
 
FTP sensor
 
EVAP canister vent solenoid valve and vent pipe for a blockage or restriction
 

Trouble Code: P0450



Fuel Tank Pressure (FTP) Sensor Performance

Possible Causes:



FTP sensor low reference circuit for an open/high resistance
 
FTP sensor 5-volt reference circuit for a short to ground or an open/high resistance.
 
FTP sensor 5-volt reference circuit for a short to voltage
 
FTP sensor signal circuit for short to ground or an open/high resistance
 
FTP sensor has failed
 
ECM has failed
 

Trouble Code: P0451



Fuel Tank Pressure (FTP) Sensor Performance

Possible Causes:



EVAP purge solenoid valve
 
FTP sensor
 
EVAP canister vent solenoid valve and vent pipe for a blockage or restriction
 

Trouble Code: P0451



Fuel Tank Pressure (FTP) Sensor Circuit High Voltage

Possible Causes:



FTP sensor signal circuit is shorted to VREF or system power
 
FTP sensor ground circuit is open between sensor and ECM
 
FTP sensor is damaged or has failed
 
ECM has failed
 

Trouble Code: P0451



Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage

Possible Causes:



FTP sensor low reference circuit for an open/high resistance
 
FTP sensor 5-volt reference circuit for a short to ground or an open/high resistance.
 
FTP sensor 5-volt reference circuit for a short to voltage
 
FTP sensor signal circuit for short to ground or an open/high resistance
 
FTP sensor has failed
 
ECM has failed
 

Trouble Code: P0452



Fuel Tank Pressure Sensor Circuit Low Input

Possible Causes:



FTP sensor connector is damaged or shorted
 
FTP sensor signal circuit is open or shorted to ground
 
FTP sensor VREF circuit is open or shorted to ground
 
FTP sensor is damaged or has failed
 
ECM has failed
 

Trouble Code: P0452



Fuel Tank Pressure (FTP) Sensor Circuit High Voltage

Possible Causes:



FTP sensor low reference circuit for an open/high resistance
 
FTP sensor 5-volt reference circuit for a short to ground or an open/high resistance.
 
FTP sensor 5-volt reference circuit for a short to voltage
 
FTP sensor signal circuit for short to ground or an open/high resistance
 
FTP sensor has failed
 
ECM has failed
 

Trouble Code: P0453



Fuel Tank Pressure Sensor Circuit High Input

Possible Causes:



FTP sensor connector is damaged, loose or open
 
FTP sensor signal circuit is shorted to VREF (5v)
 
FTP sensor ground circuit is open between sensor and ECM
 
FTP sensor is damaged or has failed
 
ECM has failed
 

Trouble Code: P0454



Fuel Tank Pressure (FTP) Sensor Intermittent

Possible Causes:



FTP sensor
 
FTP sensor 5-volt reference circuit shorted to ground or an open/high resistance
 
FTP sensor signal circuit terminal 1 for a short to voltage
 
FTP sensor signal circuit for short to ground or an open/high resistance
 
FTP sensor has failed
 
ECM has failed
 

Trouble Code: P0455



EVAP System Large Leak (0.080") Detected

Possible Causes:



Fuel filler cap is very loose, missing or the wrong part
 
Fuel tank, fuel filler neck or fuel sending unit 'O' ring is leaking
 
Fuel tank pressure sensor is damaged, disconnected or it failed
 
Fuel tank vapor line(s) is clogged, damaged or disconnected
 
Purge valve vapor line is clogged, damaged, or disconnected
 
Purge solenoid is not opening (it may be damaged or sticking)
 
Vent solenoid is not closing (it may be damaged or sticking)
 
ECM has failed
 

Trouble Code: P0455



Evaporative Emission (EVAP) System Large Leak Detected

Possible Causes:



Fuel filler cap is very loose, missing or the wrong part
 
Fuel tank, fuel filler neck or fuel sending unit 'O' ring is leaking
 
Fuel tank pressure sensor is damaged, disconnected or it failed
 
Fuel tank vapor line(s) is clogged, damaged or disconnected
 
Purge valve vapor line is clogged, damaged, or disconnected
 
Purge solenoid is not opening (it may be damaged or sticking)
 
Vent solenoid is not closing (it may be damaged or sticking)
 
ECM has failed
 

Trouble Code: P0458



Evaporative Emission (EVAP) Purge Solenoid Control Circuit Low Voltage

Possible Causes:



EVAP purge solenoid control circuit for a shorted to ground.
 
EVAP purge solenoid shorted to voltage or an open/high resistance
 
Faulty EVAP purge solenoid.
 
ECM has failed
 

Trouble Code: P0459



Evaporative Emission (EVAP) Purge Solenoid Control Circuit High Voltage

Possible Causes:



EVAP purge solenoid control circuit for a shorted to ground.
 
EVAP purge solenoid shorted to voltage or an open/high resistance
 
Faulty EVAP purge solenoid.
 
ECM has failed
 

Trouble Code: P046C



Exhaust Gas Recirculation (EGR) Position Sensor Performance

Possible Causes:



P046C
 
The difference between the actual EGR position and the desired EGR position is more than 3 percent.
 
The above condition is present for more than 10 seconds.
 

Trouble Code: P0496



EVAP Canister Purge System High Purge Flow

Possible Causes:



EVAP charcoal canister is damaged or restricted
 
EVAP purge pipe is damaged or restricted
 
FTP sensor is damaged or it has failed
 
Purge solenoid is damaged (it may be sticking)
 
Purge solenoid valve has failed
 

Trouble Code: P0497



Evaporative Emission (EVAP) Vent Solenoid Valve Control Circuit Low Voltage

Possible Causes:



Vent solenoid control circuit is open or shorted to ground
 
Vent solenoid control circuit is shorted to system power (B+)
 
Vent solenoid power circuit is open
 
Vent solenoid is damaged or has failed
 
ECM has failed
 

Trouble Code: P0502



Vehicle Speed Sensor (VSS) Absence of Signal

Possible Causes:



The difference between the two output speed signals is greater than 8 km/h (5 mph) for more than 1 second.
 

Trouble Code: P0502



Vehicle Speed Sensor (VSS) Circuit Low Voltage

Possible Causes:



P0502
 
The transmission output speed is 58 RPM or less for 5 seconds.
 

Trouble Code: P0503



Vehicle Speed Sensor (VSS) Circuit Intermittent

Possible Causes:



P0503
 
The transmission output speed drops 351 RPMs in less than 3 seconds.
 

Trouble Code: P0506



Idle Speed Too Low

Possible Causes:



Air inlet duct is collapsed, loose or air filter element is clogged
 
Base engine problem (i.e., compression or misfire condition)
 
Idle air inlet passage or throttle bore is dirty or full of deposits
 
IAC solenoid control circuit has a high resistance condition
 
IAC valve is damaged or has failed
 
MAF sensor is dirty, out-of-calibration or it is "skewed"
 
Throttle plate, throttle shaft or linkage is damaged or sticking
 
ECM has failed
 

Trouble Code: P0507



Idle Speed Too High

Possible Causes:



Engine vacuum leaks, ECM valve is leaking or the wrong valve
 
Idle air inlet passage or throttle bore is dirty or full of deposits
 
IAC valve is damaged or has failed
 
MAF sensor is dirty, "skewed" or installed improperly
 
Throttle plate, throttle shaft or linkage is damaged or sticking
 
TP sensor is out-of-range or "skewed" high
 
ECM has failed
 

Trouble Code: P050A



Engine Oil Pressure Sensor Circuit Low Input

Possible Causes:



Engine oil level it too low
 
EOP sensor signal circuit is open or shorted to ground
 
EOP sensor VREF circuit is open
 
EOP sensor is damaged or has failed
 
Instrument Cluster or ECM has failed
 

Trouble Code: P0545



Exhaust Temperature Sensor 1 (EGT-1) Circuit Low Voltage

Possible Causes:



P0545
 
The ECM detects that the EGT sensor is less than 0.32V for greater than 1 second.
 

Trouble Code: P0546



Exhaust Temperature Sensor 1 (EGT-1) Circuit High Voltage

Possible Causes:



P0546
 
The ECM detects that the EGT sensor is greater than 3.37V for greater than 1 second.
 

Trouble Code: P0562



System Voltage Low - FPCM

Possible Causes:



The FPCM detects that the battery voltage is less than 9 V.
 

Trouble Code: P0562



System Voltage Low

Possible Causes:



P0562
 
The TCM detects system voltage is 11 volts or less for 10 seconds.
 

Trouble Code: P0562



System Voltage Low

Possible Causes:



DTC P0562
 
The TCM detects system voltage is 11 volts or less for 4 seconds.
 

Trouble Code: P0563



System Voltage High - FPCM

Possible Causes:



The FPCM detects that the system voltage is greater than 17.5 V.
 

Trouble Code: P0563



System Voltage High

Possible Causes:



P0563
 
The TCM detects system voltage is 18 volts or greater for 10 seconds.
 

Trouble Code: P0563



System Voltage High

Possible Causes:



DTC P0563
 
The TCM detects system voltage is 18 volts or greater for 10 seconds.
 

Trouble Code: P0571



Cruise Control Brake Switch Circuit

Possible Causes:



The ECM detects a low voltage signal on the brake switch signal circuit when the serial data message from the BCM indicates the brakes are applied.
 

 
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