Avalanche, Sierra, Silverado, C&K Series, 1999-2005

6.6L V8 VIN 1 Std 2

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Trouble Code: P0236



Turbocharger Boost Circuit High Input

Possible Causes:



Air cleaner or intake tube is severely restricted
 
Boost sensor vacuum hose is disconnected, loose or clogged
 
Boost sensor is damaged or has failed
 
Charge air pipes or intake manifold leaking
 
EGR throttle valve is stuck closed
 
Turbocharger is damaged or has failed
 

Trouble Code: P0237



Boost Sensor Circuit Low Input

Possible Causes:



Boost sensor signal circuit shorted to sensor or chassis ground
 
Boost sensor VREF circuit open between the sensor and PCM
 
Boost sensor is damaged or has failed
 
PCM has failed
 

Trouble Code: P0238



Boost Sensor Circuit High Input

Possible Causes:



Boost sensor signal circuit is open or it is shorted to VREF
 
Boost sensor ground circuit open between sensor and the PCM
 
Boost sensor is damaged or has failed
 
PCM has failed
 

Trouble Code: P0300



Multiple Cylinder Misfire Detected

Possible Causes:



Base engine mechanical fault that affects one or more cylinders
 
Fuel injection (high pressure) nozzles or fuel lines leaking
 
Fuel injection nozzles stuck closed, dirty or restricted
 

Trouble Code: P0301



Cylinder 1 Misfire Detected

Possible Causes:



Base engine mechanical fault that affects only Cylinder 1
 
Fuel injection (high pressure) nozzle leaking only on Cylinder 1
 
Fuel injection nozzle stuck closed or dirty affecting Cylinder 1
 

Trouble Code: P0302



Cylinder 2 Misfire Detected

Possible Causes:



Base engine mechanical fault that affects only Cylinder 2
 
Fuel injection (high pressure) nozzle leaking only on Cylinder 2
 
Fuel injection nozzle stuck closed or dirty affecting Cylinder 2
 

Trouble Code: P0303



Cylinder 3 Misfire Detected

Possible Causes:



Base engine mechanical fault that affects only Cylinder 3
 
Fuel injection (high pressure) nozzle leaking only on Cylinder 3
 
Fuel injection nozzle stuck closed or dirty affecting Cylinder 3
 

Trouble Code: P0304



Cylinder 4 Misfire Detected

Possible Causes:



Base engine mechanical fault that affects only Cylinder 4
 
Fuel injection (high pressure) nozzle leaking only on Cylinder 4
 
Fuel injection nozzle stuck closed or dirty affecting Cylinder 4
 

Trouble Code: P0305



Cylinder 5 Misfire Detected

Possible Causes:



Base engine mechanical fault that affects only Cylinder 5
 
Fuel injection (high pressure) nozzle leaking only on Cylinder 5
 
Fuel injection nozzle stuck closed or dirty affecting Cylinder 5
 

Trouble Code: P0306



Cylinder 6 Misfire Detected

Possible Causes:



Base engine mechanical fault that affects only Cylinder 6
 
Fuel injection (high pressure) nozzle leaking only on Cylinder 6
 
Fuel injection nozzle stuck closed or dirty affecting Cylinder 6
 

Trouble Code: P0307



Cylinder 7 Misfire Detected

Possible Causes:



Base engine mechanical fault that affects only Cylinder 7
 
Fuel injection (high pressure) nozzle leaking only on Cylinder 7
 
Fuel injection nozzle stuck closed or dirty affecting Cylinder 7
 

Trouble Code: P0308



Cylinder 8 Misfire Detected

Possible Causes:



Base engine mechanical fault that affects only Cylinder 8
 
Fuel injection (high pressure) nozzle leaking only on Cylinder 8
 
Fuel injection nozzle stuck closed or dirty affecting Cylinder 8
 

Trouble Code: P0335



CKP Sensor Signal Range/Performance

Possible Causes:



CKP sensor signal circuit is open or shorted to ground
 
CKP sensor VREF circuit is open between the sensor and PCM
 
CKP sensor ground circuit is open
 
CKP sensor is damaged or it failed (check crankshaft sprocket)
 
PCM has failed
 

Trouble Code: P0336



Crankshaft Reference Sensor Signal Range/Performance

Possible Causes:



CKP sensor connector is damaged, loose or shorted
 
CKP sensor signal circuit is open or shorted (intermittent fault)
 
CKP sensor contacting the reluctor wheel or it has failed
 
CKP sensor is damaged or it has failed
 
PCM has failed
 

Trouble Code: P0340



CMP Sensor Circuit Malfunction

Possible Causes:



CMP sensor signal circuit is open, shorted to ground or VREF
 
CMP sensor VREF circuit is open between sensor and PCM
 
CMP sensor low reference circuit is open from sensor to PCM
 
CMP sensor is damaged or it failed
 
PCM has failed
 

Trouble Code: P0341



CMP Sensor Signal Range/Performance

Possible Causes:



CMP sensor signal circuit is open, shorted to ground or VREF
 
CMP sensor VREF circuit is open between sensor and PCM
 
CMP sensor low reference circuit is open from sensor to PCM
 
CMP sensor is damaged or it failed
 
PCM has failed
 

Trouble Code: P0370



Engine Speed Signal Circuit Malfunction

Possible Causes:



Engine speed signal circuit is open, shorted to ground or VREF
 
FICM has failed
 
PCM has failed
 

Trouble Code: P0374



Engine Speed Signal Circuit Malfunction

Possible Causes:



Engine speed signal circuit is open, shorted to ground or VREF
 
FICM has failed
 
PCM has failed
 

Trouble Code: P0380



Glow Plug Range/Performance

Possible Causes:



Glow plug relay control circuit is open, shorted to power, or the ground circuit is open
 
Glow plug relay is stuck in "on" position causing constant power
 
Glow plug relay is damaged or has failed
 
ECM has failed
 

Trouble Code: P0401



Insufficient EGR Flow Detected

Possible Causes:



EGR ports are clogged or restricted
 
EGR throttle valve vacuum control solenoid is leaking/restricted
 
EGR throttle valve is binding or sticking, or it is damaged
 
EGR throttle valve vacuum diaphragm is damaged or has failed
 
Vacuum hose from vacuum pump to EGR throttle valve diaphragm leaking or restricted
 
Exhaust system is restricted, or exhaust system was modified
 

Trouble Code: P0404



Exhaust Gas Recirculation System Malfunction

Possible Causes:



Air intake pipe is clogged or damaged
 
EGR system vacuum lines are clogged or leaking
 
EGR throttle valve throttle solenoid is damaged or it had failed
 
EGR valve vacuum sensor is damaged or it has failed
 
EGR valve vent solenoid is damaged or it has failed
 

Trouble Code: P0405



EGR Vacuum Sensor Circuit Low Input

Possible Causes:



EGR vacuum sensor connector is damaged or shorted
 
EGR vacuum sensor VREF circuit is open or shorted to ground
 
EGR vacuum sensor signal circuit is shorted to ground
 
EGR vacuum sensor is damaged or it has failed
 
ECM has failed
 

Trouble Code: P0406



EGR Vacuum Sensor Circuit High Input

Possible Causes:



EGR vacuum sensor connector is damaged or open
 
EGR vacuum sensor ground circuit is open
 
EGR vacuum sensor signal circuit is open
 
EGR vacuum sensor signal circuit is shorted to VREF
 
EGR vacuum sensor is damaged or it has failed
 
ECM has failed
 

Trouble Code: P0489



EGR Valve Vacuum Solenoid Circuit Low Input

Possible Causes:



EGR valve solenoid connector is damaged or shorted
 
EGR valve solenoid control circuit is open or shorted to ground
 
EGR valve solenoid is damaged or it has failed
 
ECM has failed
 

Trouble Code: P0490



EGR Valve Vacuum Solenoid Circuit High Input

Possible Causes:



EGR valve solenoid connector is damaged or open
 
EGR valve solenoid control circuit is open or shorted to power
 
EGR valve solenoid is damaged or it has failed
 
ECM has failed
 

Trouble Code: P0500



Vehicle Speed Sensor Circuit Malfunction

Possible Causes:



Output shaft rotor is chipped or damaged
 
Output shaft rotor is not aligned properly with the VSS unit
 
VSS tip contains debris or metal shavings (an intermittent fault)
 
VSS positive (+) signal circuit is open or shorted to ground
 
VSS negative (-) signal circuit is open or shorted to ground
 
VSS is damaged or has failed
 

Trouble Code: P0540



Intake Air Heater Circuit Malfunction

Possible Causes:



IAT relay connector is damaged, loose or shorted
 
IAT heater connector is damaged, loose or shorted
 
IAT assembly is damaged, or it has failed
 
IAH relay control circuit is open, shorted to ground or power
 
ECM has failed
 

Trouble Code: P0601



Control Module ROM Malfunction

Possible Causes:



The PCM must be replaced to correct this problem. A new PCM must be programmed with the correct software/calibration.
 
TSB 67-65-23 contains a repair procedure for this code
 

Trouble Code: P0602



Control Module Not Programmed

Possible Causes:



Reprogram the PCM with the correct software and calibration. If this step does not correct the problem, the PCM must be replaced and programmed with the correct software/calibration.
 

Trouble Code: P0603



Control Module Long Term Memory Reset

Possible Causes:



An interruption to the PCM main power and/or ground circuits
 
Check the PCM power and ground circuits and make repairs as necessary. Clear the codes and recheck. If it resets, the PCM must be replaced and programmed with the correct software.
 

Trouble Code: P0604



Control Module Random Access Memory Failure

Possible Causes:



The PCM must be replaced to correct this problem. A new PCM must be programmed with the correct software/calibration.
 

Trouble Code: P0605



Control Module Programming Read Only Memory

Possible Causes:



The PCM must be replaced to correct this problem. A new PCM must be programmed with the correct software/calibration.
 

Trouble Code: P0606



Control Module Internal Performance

Possible Causes:



The PCM must be replaced to correct this problem. A new PCM must be programmed with the correct software/calibration.
 

Trouble Code: P0607



Control Module Performance

Possible Causes:



The PCM must be replaced to correct this problem. A new PCM must be programmed with the correct software/calibration.
 

Trouble Code: P0611



Fuel Injection Control Module Performance

Possible Causes:



FICM is damaged
 

Trouble Code: P0612



Ignition Relay Control Circuit Malfunction

Possible Causes:



Ignition relay circuit is shorted to system power
 
Ignition relay is damaged or it has failed
 
ECM has failed
 

Trouble Code: P0641



5-Volt Reference 1 Circuit Malfunction

Possible Causes:



5v VREF circuit to APP1 or APP3 is shorted to ground or shorted to system power
 
FRP or EOP sensor is shorted to ground or shorted to system power
 
PCM has failed
 

Trouble Code: P0650



Malfunction Indicator Lamp Circuit Malfunction

Possible Causes:



MIL control circuit is open or shorted to ground
 
MIL control circuit is shorted to system power
 
MIL control power circuit is open in the Instrument Cluster
 
MIL (the lamp) is damaged or has failed
 
Instrument Cluster or the PCM has failed
 

Trouble Code: P0651



5-Volt Reference 2 Circuit Malfunction

Possible Causes:



5v VREF circuit to APP2 or APP2, FRP or EOP sensor is shorted to ground or shorted to VREF
 
ECM has failed
 

Trouble Code: P0802



Malfunction Indicator Lamp Circuit Malfunction

Possible Causes:



TCM MIL Request circuit is open, shorted to ground or to B+
 
ECM has failed
 
TCM has failed
 

 
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