THE CAR DOESN’T MOVE

The absolute worst situation is when a driver puts the car in D, and it isn’t moving forward at all. Numerous failing components may cause such a condition. On modern vehicles, any loss of data from critical sensors may trigger the LIMP mode. When it happens, the car will stop moving or will limit the speed under 30km/h for your safety.
Among other things, a malfunctioning module or a loss of communication between the TCM (transmission control module) and the PCM (power-train control module) is sure to bring the car to a halt.
On a simpler note, a broken shifter cable or faulty shift lock will also prevent the car from shifting from P to D.

Troubleshooting procedure:
i. Check if that the shifter is moving the switch on the transmission. Open the hood and ask an assistant to move the shift lever. Inspect the switch (locate it through owner’s manual) and confirm that it’s moving along with the shifter. If it’s not, the cable is broken and will need to be replaced.
ii. Every time a car enters the LIMP mode, a code is set in the TCM. Take out your scan tool and look out for transmission-related DTCs.
iii. Follow the designated troubleshooting chart to find the faulty component.
iv. If there are no recorded codes, the problem may come from the transmission switch itself. Using a multimeter, test the switch for continuity and verify any unwanted short-to-ground condition. Look out for blown fuses and cracked wires.
v. Once you think you have found your problem, replace the part, reconnect and reset the TCM. If the vehicle is still not moving or stuck on LIMP mode, have your vehicle towed to a transmission specialist.