Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
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Is the check engine light on? What is the mileage?
check engine light has been on evap codes, has had a new autotrans recently installed
has 169,000 miles on it.codes that are present p0449,p0452,p1639.I think what need is a diagnostic chart and a componet location chart related to evap system and or suggestions.
Ok, this sounds like there is a problem with the torque converter clutch or the valving in the valve body.
I suggest you start by looking for a code P1870 in the computer. Also check the transmission pan for debris.
Does it stumble with the brakes on period?
Ok, lets see what the crank signal, throttle position, MAP and MAF sensor do as it is stalling, not after it stalls.
cant read signals fast enough to get sound readings
No, I suspect that what you describe is normal. High idle to get things warmed up and idles down to desired as it is warned up and in or near closed loop.
No the vent is near the tank above the spare tire.
The P1639 is the 5V feed for the tank pressure sensor. The chart goes through and indicates either a problem with the wiring, sensor or the PCM.
The sensor has 3 wires, not 2.
Pink and white sounds like the vent valve not the pressure sensor.
The wiring diagram I sent has that sensor in it.