P1907 — Pressure Control Solenoid "B" Intermittent Short

OBD2 code P1907 flags a problem with the automatic transmission control (pressure control solenoid "B" intermittent short). Short, gentle driving to a shop is usually possible. Common culprits: wiring or connector faults in the valve body harness, faulty transmission speed sensor, valve body wear.

For Ford vehicles

kick down hold relay open or short circuit to ground A4LD

powertrain (engine/transmission)

Is it safe to drive?

Drive with caution Drive only if the transmission still shifts predictably, and avoid highway speeds. Driving with slipping or limp mode accelerates internal wear — every kilometre can add to the final repair bill.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm P1907 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the automatic transmission control for damage, corrosion, chafing or poor contact.
Subsystem check Check transmission fluid level and condition — dark, burnt fluid points to internal wear.
Subsystem check Read transmission-specific codes and live data (solenoid states, input/output speed) with a capable scanner.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P1907 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P1907 (parts and labor, USD, independent shop rates): Transmission fluid service: $150–$350; Transmission rebuild or replacement: $2,500–$5,500; Valve body repair or replacement: $700–$1,500; Replace a shift solenoid: $300–$800. Overall, fixing P1907 usually costs between $150 and $5,500. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

What is the most common cause of P1907?

The most common causes are: wiring or connector faults in the valve body harness, faulty transmission speed sensor, valve body wear.

What are the symptoms of P1907?

Drivers most often notice: harsh or delayed shifting, slipping between gears, Check Engine or transmission warning light on, transmission stuck in one gear (limp mode).

How much does it cost to fix P1907?

Transmission fluid service — $150–$350; Transmission rebuild or replacement — $2,500–$5,500; Valve body repair or replacement — $700–$1,500; Replace a shift solenoid — $300–$800. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

Is it safe to drive with P1907?

Drive only if the transmission still shifts predictably, and avoid highway speeds. Driving with slipping or limp mode accelerates internal wear — every kilometre can add to the final repair bill.

Will P1907 clear itself?

Sometimes P1907 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

When your vehicle's engine control module decides something is wrong with the automatic transmission, it may store trouble code P1907. This particular code points specifically to an intermittent electrical short in pressure control solenoid "B" — one of the components responsible for regulating hydraulic pressure inside the transmission. Because the fault is described as intermittent, the module won't trigger the check engine light based on a single anomaly. Instead, it waits until the irregular signal shows up repeatedly under the same driving conditions before confirming the problem and illuminating the warning lamp.

Understanding what that solenoid does helps explain why the issue matters. Pressure control solenoids work as electromechanical valves that manage fluid pressure based on commands from the transmission control unit. When solenoid "B" experiences a short — whether from damaged wiring, a failing connector, or an internal winding problem — the transmission may receive incorrect pressure commands. The transmission control module logs P1907 once it recognizes this pattern, and the associated freeze frame data records engine load, RPM, coolant temperature, and vehicle speed at that exact moment. That snapshot becomes your roadmap for recreating the fault during diagnosis.

The symptoms associated with P1907 vary depending on how severely the solenoid or supporting components are affected. Not every vehicle will display all of these signs, but the most common complaints include harsh or delayed gear changes, noticeable slipping between gears, illumination of the check engine or transmission warning light, a transmission locked into a single gear (commonly called limp mode), and in extreme cases, complete loss of forward or reverse movement. Any of these should prompt a scan for trouble codes, and if P1907 appears alongside other transmission-related codes, the underlying issue may be more complex than the solenoid itself.

Symptoms of P1907

Check Engine or transmission warning lamp illuminates on the dashboard
Harsh shifting or noticeable delay when changing gears
Slipping sensation between gears, particularly under acceleration
Transmission remains stuck in one gear (limp-home mode)
Reduced performance or inability to accelerate normally
Complete loss of movement in severe cases

Common Causes of P1907

The root cause behind P1907 typically traces back to one of several areas, ranked here from most frequently encountered to less common:

Low, contaminated, or oxidized transmission fluid reducing hydraulic efficiency
Wiring harness or electrical connector damage near the valve body (chafing, corrosion, broken pins)
Failed or weakening pressure control solenoid "B"
Worn or damaged valve body mechanical components
Internal transmission wear such as clutch deterioration or torque converter issues
Faulty output shaft speed sensor or related transmission sensor malfunction

How to Diagnose P1907

Effective diagnosis requires a systematic approach rather than jumping straight to part replacement. Follow these steps to isolate the actual cause:

Connect a quality OBD2 scanner, retrieve P1907, and record the freeze frame data. This information reveals the precise engine operating conditions — load, temperature, speed — present when the module first detected the fault.
Search for any technical service bulletins (TSB) specific to your vehicle make, model, and model year. Manufacturers sometimes publish service updates or software calibrations that address recurring P1907 complaints.
Perform a thorough visual inspection of the wiring harness and connectors associated with the automatic transmission control system. Look for frayed insulation, bent or corroded terminals, and any signs of moisture intrusion.
Inspect the transmission fluid level and condition. Healthy fluid appears bright red and smells oily; dark, brown, or burnt-smelling fluid suggests internal component wear that may accompany the electrical fault.
Use a transmission-capable scanner to pull manufacturer-specific codes and monitor live data such as solenoid operation states, input and output speed sensor readings, and commanded gear ratios.
Clear P1907 after your inspection, then drive the vehicle through a complete drive cycle that replicates the freeze frame conditions. If the code reappears, you have confirmed an active fault and can proceed confidently with repairs.

Repair Options and Costs

Once the diagnosis identifies which component is responsible, you can choose the appropriate repair. Costs below reflect typical parts and labor at independent shops in the United States:

Transmission fluid service (drain and fill or flush): $150–$350. Often the first and least expensive remedy, particularly when low fluid or degraded fluid is the culprit.
Shift or pressure control solenoid replacement: $300–$800. Direct replacement of the faulty solenoid resolves the electrical short without touching other transmission internals.
Valve body repair or replacement: $700–$1,500. The valve body houses the solenoids and related passages; significant wear or damage may require this more involved repair.
Transmission rebuild or full replacement: $2,500–$5,500. This becomes necessary when internal clutches, the torque converter, or other core components have failed beyond economical repair.

Can You Drive with P1907?

If the transmission continues to shift and the vehicle moves without slipping, short trips on city streets are generally manageable while you arrange a diagnosis. However, extended highway driving or continued operation with slipping gears risks compounding internal damage and inflating the final repair bill. The prudent choice: address P1907 promptly, and treat any sudden loss of shift quality or limp mode as a signal to stop driving immediately and have the vehicle towed.