What this code means
P2721 can indicate a possible high-input electrical concern in the A/T clutch pressure control solenoid valve D circuit.
What the vehicle may do
- The vehicle may enter fail-safe operation.
- The transmission may feel like it is missing certain shifts or not shifting normally.
Possible fault areas
- Possible solenoid control circuit concern
- Possible connector or terminal issue
- Possible wiring issue between the solenoid and PCM
- Possible PCM ground circuit issue
- Possible PCM control issue
Diagnostic path
Code overview
On this Accord, P2721 is an A/T clutch pressure control solenoid valve D high input fault. In plain terms, the PCM is seeing an electrical-side problem in that solenoid circuit. The vehicle may feel like it is missing shifts or staying in fail-safe; when this code is stored, the transmission does not shift to 2nd or 5th gear because of the fail-safe function. Keep the diagnosis focused on the electrical path: the solenoid circuit, connector and terminal condition, the wiring between the solenoid and the PCM, PCM grounds, and the PCM itself. This one is not caused by a mechanical problem inside the transmission.
Prepare and duplicate the fault
Before testing, save the freeze data and any on-board snapshot with the HDS, and make sure the basic troubleshooting checks are covered. Then select ON mode with the engine start/stop button, clear the DTC with the HDS, and check for pending or confirmed codes. If P2721 comes right back, the failure is duplicated and the next check is the solenoid current data. If P2721 does not return, treat it as an intermittent condition for now. The system is OK at this time, so concentrate on poor connections and loose terminals between A/T clutch pressure control solenoid valve D and the PCM.
Check solenoid D current data
With the fault duplicated, look at the HDS parameter for A/T C.P.C. Sol VLV. D Actual. The threshold is More than 0.035 A. If the current condition matches that threshold, A/T clutch pressure control solenoid valve D is considered OK, and the diagnosis moves to the PCM ground circuit check. If the current condition does not match that threshold, the fault is A/T clutch pressure control solenoid valve D, and the repair is to replace the secondary valve body, which includes A/T clutch pressure control solenoid valve D.
Check the PCM ground circuits
For the ground circuit check, select OFF mode with the engine start/stop button, jump the SCS line with the HDS, and disconnect PCM connector B, the 51P connector. Check continuity with the PCM connector disconnected and the vehicle in OFF mode. For GND1, check between PCM connector B, terminal No. 11, BLK wire, and body ground. For GND2, check between PCM connector B, terminal No. 20, BRN wire, and body ground. If continuity is present on these ground checks, the GND1 and GND2 wires are OK, and the repair path is to replace the PCM. If continuity is not present, repair the open in the GND1 and/or GND2 wire between the PCM and body ground G101, or repair the poor body ground at G101.
Closing takeaway
The key on P2721 is to avoid chasing a mechanical transmission problem. Duplicate the code, compare solenoid D current data to the specified threshold, and if the solenoid path passes, prove the PCM ground circuits before making the final call. For more diagnostic training, visit stepdiagnostics.com.
Final check
This code is often approached as an electrical diagnosis first, with the solenoid data and ground circuits checked in order.
For more guided automotive diagnostics, visit STEP Diagnostics.
