Pressure Control Solenoid B Intermittent
The P0779 code indicates that the transmission control module (TCM) has detected an intermittent electrical or performance issue with the pressure control solenoid B. This solenoid regulates hydraulic pressure for clutch application within the automatic transmission. Intermittent faults often stem from wiring harness damage, loose connectors, or internal solenoid wear, leading to erratic transmission behavior.
01. Most Common Causes
- Faulty pressure control solenoid B
- Damaged wiring or connectors in the solenoid circuit
- Low or contaminated transmission fluid
- Internal transmission mechanical failure
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Erratic shifting or harsh gear engagement
- Transmission slipping or delayed engagement
- Reduced fuel economy
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data to capture conditions when fault occurred.
Step 2: Inspect transmission fluid level and condition; top off or replace if necessary.
Step 3: Visually check wiring and connectors to solenoid B for damage, corrosion, or loose connections.
Step 4: Test solenoid resistance and power/ground circuits with a multimeter; compare to manufacturer specs.
Step 5: If wiring and solenoid are OK, perform a transmission pressure test to rule out internal issues.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as intermittent solenoid issues can cause sudden transmission failure or unsafe shifting, potentially leading to an accident.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, including parts (solenoid) and labor. If internal transmission damage is found, costs can exceed $1,500.