P1746 - EPC Solenoid Open Circuit
The P1746 code indicates an open circuit in the Electronic Pressure Control (EPC) solenoid, which is part of the transmission control system. The EPC solenoid regulates hydraulic pressure within the transmission to control shift feel and timing. An open circuit means there is a break in the electrical path, preventing the solenoid from functioning. This can cause harsh or erratic shifting, slipping, or even transmission damage if not addressed.
01. Most Common Causes
- Faulty EPC solenoid
- Open or shorted wiring in the solenoid circuit
- Damaged connector or poor electrical connection
- Failed transmission control module (TCM)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Harsh or delayed shifting
- Transmission slipping or stuck in gear
- Reduced fuel economy
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for additional transmission codes.
Step 2: Visually inspect the EPC solenoid connector and wiring for damage, corrosion, or loose connections.
Step 3: Measure resistance of the EPC solenoid; compare to manufacturer specifications (typically 5-20 ohms).
Step 4: Check for voltage and ground at the solenoid connector with the ignition on.
Step 5: If wiring and solenoid are okay, test the TCM output to the solenoid.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with an open EPC solenoid can cause harsh shifting, transmission slipping, and potential internal damage. Have it diagnosed and repaired promptly.
How much does it cost to fix?▼
Repair costs vary: replacing the solenoid itself is $50-$150, but labor and potential TCM replacement can bring total to $150-$400 or more.