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P0740 diagnostic code causing the check engine light to come on
2000 Chevrolet Astro

P0740 diagnostic code causing the check engine light to come on

(2000 Chevrolet Astro)
2000 Chevrolet Astro Van (4L60E transmission, 2WD). Vehicle has 73,000 miles. I have owned this vehicle since it was new.
I have a P0740 diagnostic code causing the check engine light to come on (and stay on). I also get a freeze code from my diagnostic tool that says “PID03=0202” “Loop is Open”

The transmission shifts beautifully and I can feel all upshifts as well as what I believe to be the torque converter clutch engaging at about 55 MPH when accelerating onto the freeway, however, when taking an off ramp from the freeway, the check engine light comes on during deceleration at about 43 MPH (my foot is not on the brake). I can reset the code and get the same effect every time with consistency.

I have replaced the:
TCC solenoid
PWM solenoid
Torque Converter valve in transmission valve body (without removing valve body)
Cooling system thermostat
Engine coolant temperature sensor
Transmission fluid and filter (twice)
Ignition switch
No visible nicks in any wire – loom is good.
What seems to make the problem better or worse? Does this with engine luke warm or operating temp (195 degrees)
How long have you had this problem? Almost 1 year
Tags: chevrolet, astro
1 answer & 1 comment
Popular Answer
on June 24, 2019
Should closely monitor THROTTLE POSITION SENSOR (TPS) readings to ensure there are no glitches..

May be difficult to do with scan tool as tool may update data to slowly - but it can be useful during test drive.

Good luck!
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on June 24, 2019

*While at cruising speed* .. Lightly applying brakes will unlock converter - fully releasing brakes will allow converter lockup.

This is valid test to determine IF lockup is taking place.. You’ll feel it happen.. There may be related scan tool data as well - depending on quality of tool.


(TPS plays a major role in torque converter lockup)
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on June 24, 2019
Should closely monitor THROTTLE POSITION SENSOR (TPS) readings to ensure there are no glitches..

May be difficult to do with scan tool as tool may update data to slowly - but it can be useful during test drive.

Good luck!
Sign in to reply
on June 24, 2019

*While at cruising speed* .. Lightly applying brakes will unlock converter - fully releasing brakes will allow converter lockup.

This is valid test to determine IF lockup is taking place.. You’ll feel it happen.. There may be related scan tool data as well - depending on quality of tool.


(TPS plays a major role in torque converter lockup)

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