2001 silverado 4.8L code p0404
05-28-2011, 01:24 PM
#1
2001 silverado 4.8L code p0404 I was helping my buddy with a 2001 chevy silverado 1500 with the 4.8L v8. his check engine light has been on for some time and the truck runs fine. We borrowed a scanner and found the code is a P0404. What are common causes for this and what parts should we check or replace. any help is appreciated. thanks!
05-28-2011, 03:12 PM
#2
P0404 CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) monitors the EGR valve pintle position input to ensure that the valve responds properly to commands from the PCM. The PCM compares the Exhaust Gas Recirculator (EGR) position sensor with desired EGR position when the valve is commanded open. If the difference between the EGR Position Sensor and Desired EGR Position is more than 10 percent this Diagnostic Trouble Code (DTC) will set.
CONDITIONS FOR RUNNING THE DTC
The ignition voltage is more than 11.7 volts .
The commanded EGR position is more than 0 percent .
The EGR flow test is not active.
The desired EGR position does not change more than 20 percent .
CONDITIONS FOR SETTING THE DTC
The vehicle must be driven.
The difference between the desired EGR position and the EGR position sensor is more than 10 percent .
The condition is present for more than 13 seconds .
ACTION TAKEN WHEN THE DTC SETS
The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC
The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Use a scan tool in order to clear the. MIL and the DTC.
DIAGNOSTIC AIDS
Inspect for the following conditions:
Excessive deposits on the EGR pintle or seat - Remove the EGR valve and inspect for deposits that may interfere with the EGR valve pintle extending completely or cause the pintle to stick.
The Powertrain Control Module (PCM) monitors the EGR valve pintle position input to ensure that the valve responds properly to commands from the PCM. The PCM compares the Exhaust Gas Recirculator (EGR) position sensor with desired EGR position when the valve is commanded open. If the difference between the EGR Position Sensor and Desired EGR Position is more than 10 percent this Diagnostic Trouble Code (DTC) will set.
CONDITIONS FOR RUNNING THE DTC
The ignition voltage is more than 11.7 volts .
The commanded EGR position is more than 0 percent .
The EGR flow test is not active.
The desired EGR position does not change more than 20 percent .
CONDITIONS FOR SETTING THE DTC
The vehicle must be driven.
The difference between the desired EGR position and the EGR position sensor is more than 10 percent .
The condition is present for more than 13 seconds .
ACTION TAKEN WHEN THE DTC SETS
The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC
The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Use a scan tool in order to clear the. MIL and the DTC.
DIAGNOSTIC AIDS
Inspect for the following conditions:
Excessive deposits on the EGR pintle or seat - Remove the EGR valve and inspect for deposits that may interfere with the EGR valve pintle extending completely or cause the pintle to stick.
