What Does P0779 Mean?
The TCM has detected an intermittent electrical fault in the Pressure Control Solenoid B circuit. The solenoid's electrical signal is inconsistently dropping out or spiking, indicating a connection that is marginally failing. This intermittent behavior makes diagnosis challenging because the fault may only manifest under specific temperature, vibration, or load conditions.
Common Causes
30%
Intermittent PCS B solenoid coil failure (thermal-sensitive open or short)
30%
Loose or corroded pins in the transmission connector causing intermittent contact
20%
Chafed or partially broken wire in the transmission harness
12%
TCM connector with marginal pin contact
8%
Intermittent TCM driver circuit fault
Diagnostic Steps
1
Review freeze frame data to identify the operating conditions when the intermittent fault occurs — note temperature, RPM, and vehicle speed.
2
Inspect all connectors in the PCS B circuit for signs of corrosion, moisture, pushed-back pins, or loose terminal tension.
3
Measure solenoid resistance at room temperature and again at full operating temperature to detect thermal-sensitive coil failure.
4
Perform a thorough wiggle test on the wiring harness while monitoring the PCS B circuit with a multimeter or scope for dropouts.
5
Check for manufacturer TSBs addressing connector or harness issues specific to the vehicle model.
6
If no external fault is found, replace PCS B as intermittent internal failures are difficult to definitively catch on a bench test.
Estimated Repair Cost
$150 - $900
Parts + labor, varies by vehicle and location
The TCM has detected an intermittent electrical fault in the Pressure Control Solenoid B circuit. The solenoid's electrical signal is inconsistently dropping out or spiking, indicating a connection that is marginally failing. This intermittent behavior makes diagnosis challenging because the fault m...
The most common cause of P0779 (Pressure Control Solenoid B Intermittent) is: Intermittent PCS B solenoid coil failure (thermal-sensitive open or short)
Typical repair costs for P0779 range from $150 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Intermittent pressure control issues may cause unpredictable shift quality changes, momentary slipping, or brief limp mode events. The vehicle is generally drivable but the unpredictable behavior warrants timely diagnosis, especially for daily commuters.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0779 to identify the root cause.
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Quick Info
Category
Powertrain
System
Automatic Transmission
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
