This code reads and says small emission leak in evap sensor. I have changed the gas cap and done numerous checks of everything i could think of. I am lost it passes smog butif anybody has had the same issue and knows what to fix let me know it would really be appreciated. Its a 2000 sl2 Edited by: 24sl2

 

usually that has to do with the EGR valve. It may be a faulty EGR valve or just a vacuum line going to it that is leaking

 

p0404 deals with the evap system you have to perform at purge and seal test,,,and you can do a smoke test it will pump nitrogen through your evap system so you can find the leak

 

Can I do this purge test myself, what partswould I need. And how would I do this

 

DTC P1404

The exhaust gas recirculation (EGR) valve consists of a pintle valve which moves by the use of an internal solenoid and an internal position sensor, potentiometer, used to determine pintle valve position. The powertrain control module (PCM) controls the solenoid by supplying it ignition voltage whenever exhaust gas needs to be recirculated into the intake manifold. The PCM monitors the EGR solenoid and position sensor circuits for correct voltage levels at certain times. The PCM will also monitor the position of the sensor in relation to its duty cycle, commanded On-time. DTC P1404 sets when the EGR sensor signal voltage is above the calibrated voltage value when the valve is commanded closed.

DTC Parameters
DTC P1404 will set if the actual EGR position is greater than 4 percent when:

The commanded EGR position equals 0 percent.
The condition exists for longer than 20 seconds.
The engine speed is less than 5,000 RPM.
The EGR valve has been commanded to cycle greater than 61 percent 4 times.
The ignition voltage is greater than 11 volts.
OR

The actual EGR position is greater than 7.8 percent when:

The commanded EGR position equals 0 percent.
The condition exists for longer than 20 seconds.
The engine speed is greater than 5,000 RPM.
The EGR valve has been commanded to cycle greater than 61 percent 4 times.
The ignition voltage is greater than 11 volts.
DTC P1404 diagnostic runs continuously once the above conditions have been met and the engine is running.

DTC P1404 is a type A DTC.

Diagnostic Aids
If DTC P0403 or P1403 is set, diagnose that DTC first. A diagnosed EGR solenoid fault will cause this DTC to set.

Use a scan tool to command the EGR SOLENOID ON (pulse width modulation - PWM), while monitoring the EGR SENSOR. The values for the EGR SENSOR at a commanded state of 0 percent and 70 percent should fall within these ranges:

0 percent commanded state equals 0.5-1 volts from EGR SENSOR.

70 percent commanded state equals 4.2-4.7 volts from EGR SENSOR.

An open in circuit 452 or short to voltage on circuit 1456 will set this DTC.

Debris or binding pintle shaft holding EGR valve open may also set this DTC.
Edited by: Low Saturn