What this code means
P0720 may mean the vehicle speed signal being used by the driver-assist camera or ACC-related system does not agree with expected vehicle speed information.
What the vehicle may do
- The vehicle may show an ACC or driver-assist related warning or indicator.
- The system may behave normally at times if the fault is intermittent.
- The concern can often depend on road-test conditions being reproduced.
Possible fault areas
- Possible related areas can include VSA system code issues, communication-related concerns, PCM vehicle speed data, multipurpose camera unit software, and multipurpose camera unit.
- Connector terminal condition may also be involved.
Diagnostic path
Opening context
On this 2010 to 2016 Honda CR-V with the 2.4 gas engine, P0720 is a vehicle speed signal error in the multipurpose camera and ACC side of the system. In plain terms, the camera and ACC system may not be seeing vehicle speed the same way the rest of the vehicle is. The driver may notice an ACC or driver-assist related warning, and the broad fault areas can include the speed signal path through the VSA system, PCM data, multipurpose camera software, or connector condition. Before chasing the camera, start with the basic system checks, and if communication-related codes are stored at the same time, handle those first, then come back and recheck P0720.
Check for other system codes first
Start by checking the VSA system for DTCs with the HDS. If any VSA codes are present, follow that indicated diagnostic path first. If no VSA codes are present, continue into the vehicle speed signal check for the multipurpose camera unit.
Compare camera-side vehicle speed data
Clear the code with the HDS, turn the vehicle to OFF LOCK, then road test it with ACC activated. The road test needs to be done at 25 mph (40 km/h) or more, and this check is done on the road, not on a lift. Watch the vehicle speed signal in the ACC system data and compare it to the speed shown in the gauge control module. If the HDS speed matches the gauge, treat it as an intermittent fault for now. If captured data is available for this code, try to reproduce the same conditions. If the ACC-side speed does not match the gauge, move on to the PCM speed data check.
Compare PCM vehicle speed data
Next, road test the vehicle again with ACC activated at 25 mph (40 km/h) or more. Again, keep it on the road, not on a lift. This time, look at the vehicle speed parameter in the PGM-FI system data with the HDS, and compare that to the speed shown in the gauge control module. If the PCM speed data does not match the gauge, the path moves away from the camera and into PGM-FI system troubleshooting. If the PCM data does match the gauge, continue to the camera unit software and connector side of the diagnosis.
Update, recheck, and make the final call
Now check the multipurpose camera unit software. If it does not have the latest software, update it. After that, turn the vehicle to OFF LOCK, road test it with ACC activated at 25 mph (40 km/h) or more, and keep the vehicle on the road, not on a lift. Then check for DTCs with the HDS. If P0720 is still indicated, check for loose terminals at the multipurpose camera unit 20P connector. If the multipurpose camera unit was updated and the symptom or indicator is still present, replacement of the multipurpose camera unit is supported by this path. If P0720 does not return, the troubleshooting is complete. If any other codes are present after that, check what they mean separately.
Takeaway
The key on P0720 here is to prove where the speed signal stops making sense: VSA codes first, then ACC-side speed data, then PCM speed data, then camera software and connector checks. Don’t condemn the camera until the earlier speed data path supports it. For more diagnostic training, visit stepdiagnostics.com.
Final check
Follow the speed signal comparison path before making a decision on the multipurpose camera unit.
For more guided automotive diagnostics, visit STEP Diagnostics.
