What this code means
This code may indicate that A/T clutch pressure control solenoid valve C is stuck on, meaning the transmission may be applying or holding clutch pressure when it should not.
What the vehicle may do
- The vehicle may have abnormal shift feel.
- The transmission may shift harshly or inconsistently.
- The code may return during a drive cycle.
Possible fault areas
- ATF level, condition, or leaks may be involved.
- Internal metal debris or clutch material may be involved.
- A/T clutch pressure control solenoid valve C operation may be involved.
- The hydraulic circuit related to shift valve C may be involved.
Diagnostic path
Open and setup
On this 2010 to 2015 Honda Civic with the 1.8 gas engine, P0797 points to A/T clutch pressure control solenoid valve C being stuck on. In plain language, the transmission may be applying or holding clutch pressure when it should not. The vehicle may have abnormal shift feel, harsh or inconsistent shifting, or the code may come back during a drive cycle. Possible fault areas can include the fluid level or condition, fluid leaks, internal clutch or metal debris, solenoid valve C operation, and the hydraulic circuit related to shift valve C. Before starting, record all freeze data and any on-board snapshot with the HDS. Then keep the diagnosis structured and stay in order.
Start with the ATF check
First, warm the engine up to normal operating temperature, when the radiator fan comes on. Make sure the transmission is filled to the proper level, and check for fluid leaks. Then drain the ATF through a strainer and inspect the strainer for metal debris or excessive clutch material. If the strainer has metal debris or excessive clutch material, the path calls for replacing the transmission, then verifying the repair. If the strainer does not have that debris or clutch material, replace the ATF and continue to the code verification drive.
Verify the fault
Next, turn the ignition switch to ON (II), clear the DTC with the HDS, and test-drive the vehicle with the shift lever in D. Let the transmission shift through all five gears. While doing that, monitor the OBD STATUS for P0797 with the HDS. If the HDS indicates FAILED, the failure is duplicated, so move into the solenoid operation check. If the HDS indicates PASSED, treat it as an intermittent failure, and the system is OK at this time. If it says NOT COMPLETED, test-drive again until the status completes.
Command solenoid valve C with the scan tool
Now clear the DTC with the HDS again. Use the HDS to test A/T clutch pressure control solenoid valve C. If the HDS indicates NORMAL, solenoid valve C is OK, and this is treated as an intermittent failure with the system OK at this time. If the HDS indicates a failure, follow the HDS direction for that test result. If the HDS has not determined the cause of the failure, continue to the direct solenoid valve C check. If a part is replaced during that scan-tool-directed path, keep verification separate and verify the repair afterward. Because that failure path has two possible outcomes, do not guess past the HDS result; pause and recheck the earlier diagnostic path if the next move is not clear.
Inspect solenoid valve C and decide the repair path
If the scan tool test does not settle the cause, inspect A/T clutch pressure control solenoid valve C. The question here is simple: does solenoid valve C work properly? If it does work properly, the solenoid is OK, so repair the hydraulic circuit related with shift valve C, or replace the transmission, then verify the repair. If solenoid valve C does not work properly, replace A/T clutch pressure control solenoid valve C, then verify the repair.
Verify the repair
For repair verification, turn the ignition switch to ON (II), clear the DTC with the HDS, and test-drive the vehicle with the shift lever in D. Let the transmission shift through all five gears, and monitor the OBD STATUS for P0797. If the HDS indicates PASSED, troubleshooting is complete. After this code is handled, check for other DTCs, and if any other pending or confirmed codes are present, check what they mean next. If the HDS indicates FAILED, go back to the solenoid valve C operation check and recheck the path. If it says NOT COMPLETED, meet the test condition and check the OBD STATUS again. The takeaway is: prove the fluid and debris condition first, duplicate the fault, command the solenoid, then separate the solenoid decision from the hydraulic circuit decision. For more diagnostic training, visit stepdiagnostics.com.
Final check
This diagnostic path often works best when the fluid and debris check is handled first, the fault is duplicated with the HDS, and solenoid testing is kept separate from final repair verification.
For more guided automotive diagnostics, visit STEP Diagnostics.
