The lift will not incline now in normal mode, but in Maintenance mode manual it inclines and declines, code Incline Inoperative Continue if Desired. What steps should I follow. Thank you Ernesto

If you've already replaced the lift motor on your Proform 400s Treadmill and the incline still won't work properly, there may be other underlying issues that need to be addressed. Here are a few troubleshooting steps you can try:
Check the wiring: Ensure that all the wiring connections related to the incline mechanism are secure and properly connected. Loose or damaged wiring can cause issues with the incline functionality.
Inspect the incline motor and gears: Examine the incline motor and gears for any signs of damage, misalignment, or obstruction. Ensure that the gears are engaging properly and that there are no obstructions preventing the incline from moving up and down smoothly.
Reset the treadmill: Perform a full system reset on your treadmill. This can often resolve minor software glitches or issues that may be affecting the incline function. Consult your treadmill's user manual for instructions on how to perform a reset.
Contact customer support: If you have followed the above steps and the issue persists, it is recommended to reach out to the customer support of Proform or the retailer from whom you purchased the treadmill. They should be able to provide further troubleshooting guidance or arrange for professional repair assistance if needed.
Remember to exercise caution when working with electrical components or performing any repairs on your treadmill. If you are unsure or uncomfortable with the process, it is advisable to seek assistance from a qualified technician or the manufacturer's customer support to ensure proper diagnosis and resolution of the issue.

Method 1: Press Stop and Speed Up, Insert the Key
To calibrate the incline, press and hold the stop and speed increase buttons. While holding the buttons, insert the safety key. The machine will now be in calibration mode. Press the Stop button once. Then, press one of the incline buttons to begin the calibration. It is recommended that you do not stand on the machine while the calibration is taking place.
The machine will move to its highest incline position, then to its lowest decline position. Please wait for the machine to come to a complete stop. When the machine stops moving, the calibration is complete. Remove the safety key from the console to exit calibration mode.
Method 2: Press the Stop Button, Insert the Key
To calibrate the incline, press and hold the stop button. While holding the button, insert the safety key into the console. The machine will now be in calibration mode. Press the stop button once. Then, press either the incline up or incline down button to begin the calibration. It is recommended that you do not stand on the machine while the calibration is taking place.
The machine will move to its highest incline position, then to its lowest decline position. Please wait for the machine to come to a complete stop. When the machine stops moving, the calibration is complete. Remove the safety key from the console to exit calibration mode.

An E6 or E7 error code is an incline error code. The E7 code means the potentiometer value the console is reading from the lift motor is out of range. This can happen when there is a bad wire harness connection or a damaged wire harness. It could also just mean the incline motor needs to be adjusted back into range. If all wire connections look ok, the incline motor will need to be adjusted.

1. Turn the power OFF, wait 5-seconds and turn back ON.
2. Get into test mode and enter through the I/O testing step. This screen will display the potentiometer value of the incline motor. Different models will have different values. Check to see if the running deck is raised to high incline level or if it is at the low level. If the running deck is at a low position press the incline up button. This will cause the incline motor to raise the running deck up. When the deck gets to a mid-level position, press the incline up button a second time to stop the deck. If the running deck is in a high incline position, use the incline down button to adjust the deck to a mid-level position.
3. Once the unit is in the mid-level position, power the treadmill off for 5-seconds and then power it back ON.
4. Start the treadmill.
5. Once the treadmill starts the running deck will move to the level 0 position. If this does not resolve the issue or it will not adjust please contact customer service.

Also note that not all models will have the ability to adjust the incline motor. If the adjustment procedure is not found in the Owner's Manual then contact customer service.

You've to check the incline and decline limit switches also the incline motor
If you wish to get some details about treadmill repair and service ; check the site linked here. Pull up older posts.
http://electro-medical.blogspot.com/

Hi,
Try to do the following hope it will solve the problem.
if its doesn't solve the problem then the the incline motor or the control panel is faulty.
HOW TO USE THE SETTINGS MODE T
he console features a settings mode that allows you to connect your incline trainer to your own wireless network and to log in to your iFit Live account. The settings mode also allows you to turn on and turn off the display demo mode. You may also be able to select the unit of measurement.
Select the settings mode.
Insert the key into the console . Next, select the start menu. Then, press the i button in the lower right corner of the screen to select the settings mode.
Select the maintenance mode.
Press the Maintenance button in the lower right corner of the screen to enter the maintenance mode.
Calibrate the incline system of the incline trainer.
Press the Calibrate Incline button. The incline trainer will automatically rise to the maximum incline level, lower to the minimum incline level and then return to the starting position. This will recalibrate the incline system. Press the Begin button to calibrate the incline system or the Cancel button to return to the maintenance mode. When the incline system is calibrated, press the Back button. IMPORTANT: Keep pets, feet, and other objects away from the incline trainer while the incline is calibrating. In an emergency, pull the key from the console to stop the incline calibration.
Restore factory defaults.
If necessary, press the Restore Defaults button to reset the firmware to the original factory firmware. This will erase all firmware updates that you have downloaded. Press the Begin button to restore the default firmware or the Cancel button to return to the maintenance mode. When the restoration is complete, the words PLEASE CYCLE POWER will appear in the grey box. Press the power switch into the off position. Wait for several seconds, and then press the power switch into the reset position. It may take a minute for the console to be ready for use.
Exit the maintenance mode.
To exit the maintenance mode, press the Back button repeatedly.
www.electro-medical.blogspot.com

This is conjecture but the incline motor is likely attached to a worm gear that lifts and then lowers the incline. There is also likely some kind of automatic "clutch" that disengages the motor from the worm drive after the raise or lower sequence is complete. If this clutch is broken or malfunctioning, then it may be trying to "grab" the worm gear when it is not supposed to (when not raising or lowering) or conversely, it may be losing its grip on the worm gear when the incline is happening. The clutch is likely controlled by an electric solenoid which may be malfunctioning. All this to say that it may be time to call a repair person.

Bad contact in the switch

Hi there, checked both upper and lower bolted connections, and check that lift motor hasn't cracked and frame is intact with no blockages to a possible scissor arm-lift assembly underneath the unit ? If this all checks out, maybe a small gearbox on the lift motor failed internally. Good luck.

Get back into System test hit enter it will automatically to a check once completed. Then go to Lift motor module Go to manual incline and go to maximum incline then to 0 incline then get out of system test unplug unit for about 30 seconds. Then plug unit in if this does not work the limit or home switch may be the culprit

My wife had the same problem with her treadmill. I turned the beast on it's side, and unscrewed the plastic casing that houses the motor, computer, and all the electronics to the treadmill. I unplugged the incline/decline motor. Then on the bottom of the treadmill the long threaded rod that causes the incline needed to be moved. So I unbolted it from the catch, and manually screwed the rod back in with a wrench. Now the treadmill works fantastically, of course the incline/decline mechanism has been disabled, but I would rather have a treadmill with the incline disabled than have one always on 100% incline. Hope you found this helpful :)