What this code means
P0720 may mean a control module is seeing vehicle speed information that does not agree with expected speed signals from related systems.
What the vehicle may do
- The vehicle may show warning lights or driver-assist messages.
- Some systems can reduce or disable functions that depend on reliable vehicle speed information.
- The concern may be intermittent if the signal or connection problem is not present all the time.
Possible fault areas
- Possible communication faults between modules.
- Possible transmission speed-sensor signal concerns.
- Possible connector terminal fit or poor connection at the multipurpose camera unit.
- Possible multipurpose camera unit concern after related checks pass.
Diagnostic path
Opening context
On this Honda Accord, P0720 is being handled as a vehicle speed signal error seen by the multipurpose camera unit. In plain language, the module may not be seeing a vehicle speed signal that lines up with what the rest of the vehicle is reporting. The driver may notice warning lights or system messages, and the issue can involve communication faults, transmission speed-sensor information, connector problems, or the multipurpose camera unit itself. Treat this like a plausibility diagnosis: do not jump straight to a part. First make sure the other systems that supply or validate vehicle speed are clean.
Check for higher-priority codes first
Start with the basic system checks. Turn the vehicle to ON mode and use the HDS to check the PGM-FI system for codes. If any codes are present there, check what they mean first before continuing this P0720 path. If PGM-FI is clear, move to the A/T system and check it the same way. If the A/T system has codes, handle those first. If it is clear, check the CVT system for codes. Again, if codes are present, diagnose those before continuing. Then check the VSA system. If VSA has codes, deal with those first. If all of those checks are clear, continue with P0720 verification.
Handle communication faults before P0720
One important shortcut here: if communication codes are stored at the same time as P0720, diagnose the communication problem first, then come back and recheck for P0720. A bad or missing network message can make a speed-signal plausibility code look like a sensor or module fault when it is not.
Verify the problem
Once the preliminary code checks are clear, verify the problem. Clear the code with the HDS, turn the vehicle OFF, then test-drive the vehicle at 25 mph (40 km/h) or more. After the drive, check codes again with the HDS. If P0720-62 does not come back, treat it as an intermittent failure and the system is OK at this time. If P0720-62 does return, the next step depends on the transmission type.
CVT path
For a CVT vehicle, run the CVT speed-sensor related checks next. The key point is that the monitor for P0720 and the monitors for the related CVT speed-sensor faults do not use the exact same detection conditions. So even if the PCM or TCM is not currently storing those related speed-sensor codes, still perform the CVT speed-sensor diagnostic checks when P0720-62 is the fault being confirmed first. If that check is not OK, the fault is in the CVT speed-sensor related area. If that check is OK and the failure has been duplicated, inspect the multipurpose camera unit 20P connector for loose terminals and poor connections. Also check for any applicable service information related to the codes or symptoms being diagnosed. If those checks are OK, replace the multipurpose camera unit.
A/T path, first speed-sensor check
For an A/T vehicle, go to the input shaft, or mainshaft, speed-sensor related checks. Same idea here: P0720 can be confirmed before the related speed-sensor faults are stored in the PCM or TCM, because the detection conditions are different. So run those input shaft speed-sensor checks even if those companion codes are not stored. If the check is not OK, stay in that input shaft speed-sensor related fault area. If the check is OK, continue to the output shaft speed-sensor check.
A/T path, second speed-sensor check
Next, run the output shaft, or countershaft, speed-sensor related checks. Again, do not skip this just because the PCM or TCM is not storing the related output shaft speed-sensor codes. If that check is not OK, the fault is in the output shaft speed-sensor related area. If the check is OK and the failure has been duplicated, inspect the multipurpose camera unit 20P connector for loose terminals and poor connections. Check for any applicable service information related to the codes or symptoms being diagnosed. If those checks are OK, replace the multipurpose camera unit.
Closing takeaway
The takeaway on P0720 is to prove the code first, then separate a real speed-sensor related problem from a signal plausibility problem at the multipurpose camera unit. Clear the code, reproduce the drive condition, follow the correct CVT or A/T path, and only condemn the camera unit after the related speed-sensor checks and connector checks pass. For more diagnostic training, visit stepdiagnostics.com.
Final check
P0720 is often a plausibility-style diagnosis, so the broad goal is to confirm the code, rule out related system faults, then inspect the camera unit connection before considering the module.
For more guided automotive diagnostics, visit STEP Diagnostics.
