What this code means
P1890 may indicate a problem in the CVT speed control system.
What the vehicle may do
- The vehicle may have abnormal CVT operation.
- The code can sometimes appear with limited noticeable symptoms.
- The concern may be intermittent.
Possible fault areas
- Possible CVT speed control system issue.
- Possible transmission control or transmission-related fault area.
- Possible intermittent operating-condition-related concern.
Diagnostic path
Opening context
On this Civic, P1890 points to a possible issue in the CVT speed control system. The driver may notice abnormal CVT behavior, or the code may show up with limited symptoms. Broadly, this can involve the transmission control side of the CVT speed control logic, an intermittent condition, or a transmission-related fault. Before getting deep into the code, start with the basic system checks and follow a structured diagnostic approach so you are not chasing a symptom caused by another stored problem.
Check for other codes first
Start by turning the ignition ON, or selecting ON mode with the engine start stop button. Then use the HDS to check for pending or confirmed codes. If any code other than P1890 is present, handle that diagnostic path first. If P1890 is the only code, continue with the P1890 problem verification.
Clear the code and reproduce the condition
For the verification drive, turn the ignition ON again, or select ON mode. Clear the code with the HDS. Start the engine and let it warm up to normal operating temperature, which is when the radiator fan comes on twice. Then test drive the vehicle in D on a flat road. Accelerate slowly until vehicle speed reaches 37 mph (60 km/h), then hold the vehicle at about 37 mph (60 km/h) for at least 60 seconds.
Read the monitor result
After the drive, stay in the DTC menu on the HDS and monitor the OBD status for P1890. If the HDS shows FAILED, the fault has been duplicated, and the specified repair path is transmission replacement. If the HDS shows PASSED, treat it as an intermittent failure and the system is OK at this time. If captured condition data is available for this code, try to reproduce the failure under those same conditions. If the HDS shows NOT COMPLETED, repeat the test drive so the monitor can finish.
Closing takeaway
The key with P1890 is not to guess early. Check for other codes first, clear it, warm the car up, run the exact drive condition, and let the HDS status decide whether the fault duplicated or whether you are dealing with an intermittent condition. For more diagnostic training, visit stepdiagnostics.com.
Final check
Confirm whether the fault can be duplicated under the required operating condition before making a repair decision.
For more guided automotive diagnostics, visit STEP Diagnostics.
