What is diagnostic code 07020 in a jeep grand Cherokee?
P0720 - Low Output SPD Sensor RPM Above 15 MPH
The relationship between the Output Shaft Speed Sensor and vehicle speed is not within acceptable limits. P0720 - Low Output SPD Sensor RPM Above 15 MPH
Output shaft speed is less than 60 rpm with vehicle speed above 15 mph (4-speed auto. trans. only).
I don't know about a Grand Cherokee, but in a 2005 Jeep Wrangler you turn your ignition 3 times with out turning the motor over. Turn your key to start, then off, then start, then off, then start and leave in start position, a code will be displayed in the odometer area. Maybe its the same for a Grand Cherokee. If that doesn't work a scan tool is required.