Pressure Control Solenoid B Intermittent
The P0779 code indicates that the transmission control module (TCM) has detected an intermittent electrical fault in the pressure control solenoid B circuit. This solenoid regulates hydraulic pressure to the transmission clutches and bands for smooth shifting. An intermittent signal suggests a loose connection, damaged wiring, or a failing solenoid that works sporadically, leading to erratic transmission behavior.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Erratic or harsh shifting
- Transmission slipping or delayed engagement
- Reduced fuel economy
2. Most Common Causes
- Faulty pressure control solenoid B
- Damaged or corroded wiring/connectors in solenoid circuit
- Low or contaminated transmission fluid
- Internal transmission mechanical failure
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Inspect transmission fluid level and condition; top off or replace if necessary.
Step 3: Visually check wiring and connectors for damage, corrosion, or loose connections.
Step 4: Test solenoid resistance and power/ground circuits with a multimeter.
Step 5: If wiring is good, replace pressure control solenoid B.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as intermittent solenoid failure can cause transmission damage or unsafe driving conditions.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, including parts and labor, depending on vehicle make and model.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.