What this code means
P1747 may indicate that the automatic transmission controller has detected a possible hydraulic control system problem.
What the vehicle may do
- The vehicle may shift abnormally.
- The transmission may have trouble completing normal gear changes.
- The vehicle can sometimes feel normal if the concern is intermittent.
Possible fault areas
- Possible ATF level, leak, or fluid condition concern.
- Possible internal transmission material concern.
- Possible cut valve A or cut valve B hydraulic control concern.
- Possible internal transmission concern.
Diagnostic path
Opening context
On this 2010-2015 Honda Civic with the 1.8 L engine, P1747 is a hydraulic control system code for the automatic transmission. In plain language, the controller may be seeing a hydraulic control problem that can affect how the transmission applies and shifts. The car may shift abnormally, may not complete the normal shift pattern during the check, or it may act normal if the fault is intermittent. The broad areas in this path are the ATF level and condition, signs of internal transmission material, and the cut valve A or cut valve B hydraulic control area.
Start with captured data and basic checks
Before doing anything else, save the freeze data and any on-board snapshot with the HDS. Then start with the basic system checks so you are not chasing this code without the operating history that set it.
ATF condition check
Begin the hydraulic check by warming the engine to normal operating temperature. In this procedure, that means the radiator fan comes on. Then make sure the transmission is filled to the proper level, and check for fluid leaks. After that, drain the ATF through a strainer and inspect the strainer for metal debris or excessive clutch material.
Decision from the strainer inspection
If the strainer shows metal debris or excessive clutch material, the path calls for replacing the transmission, then moving to repair verification. If the strainer does not show that material, replace the ATF, then continue into the code verification drive.
Duplicate the fault
For problem verification, turn the ignition switch to ON (II), clear the DTC with the HDS, then test-drive the vehicle with the shift lever in D. Let the transmission shift through all five gears. After the drive, watch the OBD STATUS for P1747 in the HDS DTC menu.
Interpret the problem verification result
If the HDS shows FAILED, the fault has been duplicated. This path points to a faulty cut valve A or cut valve B, and the supported repairs are replacing the main valve body for cut valve B, the servo body for cut valve A, or the transmission. After that, go to repair verification. If the HDS shows PASSED, treat it as an intermittent failure and the system is OK at this time. If it shows NOT COMPLETED, run the test-drive again under the needed conditions.
Verify the repair
Keep repair verification separate from the diagnostic decision. Turn the ignition switch to ON (II), clear the DTC with the HDS, then test-drive the vehicle in D and let the transmission shift through all five gears. Monitor the OBD STATUS for P1747 again in the HDS DTC menu.
Final verification result and takeaway
If the HDS shows PASSED, troubleshooting for P1747 is complete. After that, check for any other pending or confirmed codes, and if any are present, check what they mean next. If P1747 shows FAILED during verification, go back through the earlier diagnostic path and recheck. If it shows NOT COMPLETED, meet the test conditions and check the OBD STATUS again. The takeaway is simple: for P1747, prove the ATF and internal material condition first, duplicate the code with the HDS, and keep the final verification as its own step. For more diagnostic training, visit stepdiagnostics.com.
Final check
P1747 often needs a hydraulic-condition-first diagnosis, followed by scan tool confirmation and a separate verification drive.
For more guided automotive diagnostics, visit STEP Diagnostics.
