P0777 - Pressure Control Solenoid B Stuck On
The P0777 code indicates that the transmission control module (TCM) has detected that the pressure control solenoid B is stuck in the 'on' position, causing excessive hydraulic pressure in the transmission. This can lead to harsh shifts, slipping, or transmission damage. The solenoid regulates fluid pressure to control shift timing and feel; when stuck on, it may cause the transmission to apply too much pressure, resulting in erratic behavior.
01. Most Common Causes
- Faulty pressure control solenoid B
- Wiring or connector issues in the solenoid circuit
- Low or contaminated transmission fluid
- Internal transmission mechanical failure
02. Symptoms You Will Notice
- Harsh or delayed shifts
- Transmission slipping or overheating
- Check Engine Light illuminated
- Reduced fuel economy
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Check transmission fluid level and condition; top off or replace if necessary.
Step 3: Inspect wiring and connectors to the pressure control solenoid B for damage or corrosion.
Step 4: Test solenoid resistance and operation using a multimeter and scan tool; replace if out of spec.
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 it can cause transmission damage. Limited driving to a repair shop is acceptable if the transmission is not slipping severely.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, including parts and labor. Solenoid replacement is common, but if internal damage is found, costs can exceed $1,000.