P0747 — Pressure Control Solenoid A Stuck On

OBD2 code P0747 flags a problem with the automatic transmission control (pressure control solenoid a stuck on). Short, gentle driving to a shop is usually possible. Common culprits: low or degraded transmission fluid, wiring or connector faults in the valve body harness, faulty transmission speed sensor.

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 P0747 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 Command the pressure control solenoid a on and off with a scanner and watch the feedback signal; then remove and inspect the mechanism for sticking before replacing it.
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 P0747 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P0747 (parts and labor, USD, independent shop rates): Valve body repair or replacement: $700–$1,500; Transmission rebuild or replacement: $2,500–$5,500; Transmission fluid service: $150–$350; Replace a shift solenoid: $300–$800. Overall, fixing P0747 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

How do I diagnose P0747 myself?

Start with a scan: confirm P0747, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the pressure control solenoid a, and verify the suspect component against live data before buying parts.

How much does it cost to fix P0747?

Valve body repair or replacement — $700–$1,500; Transmission rebuild or replacement — $2,500–$5,500; Transmission fluid service — $150–$350; 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.

What are the symptoms of P0747?

Drivers most often notice: Check Engine or transmission warning light on, slipping between gears, no movement in severe cases, shuddering at highway speed.

Is it safe to drive with P0747?

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.

What is the most common cause of P0747?

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

When your vehicle's computer detects that the automatic transmission's primary pressure control solenoid isn't responding as commanded, it triggers fault code P0747. Officially labeled "Pressure Control Solenoid A Stuck On," this powertrain code indicates the solenoid mechanism has seized in its active position and cannot modulate transmission line pressure properly. The transmission control module (TCM) or powertrain control module (PCM) continuously monitors solenoid operation throughout driving, comparing commanded states against actual feedback signals to verify proper function.

The pressure control solenoid governs hydraulic pressure within the valve body, directing fluid to engage clutches and bands at precisely the right moment. When this solenoid gets stuck in the "on" or open position, it forces constant maximum pressure through the system. This throws off shift timing, causes harsh engagements, and can damage internal components if ignored. P0747 specifically refers to solenoid A, which typically handles line pressure regulation in many automatic transmissions found across different manufacturers.

When the solenoid fails to respond—either remaining stuck open when it should close, or refusing to close when commanded open—the module logs this discrepancy and sets P0747 after confirming the condition across multiple drive cycles. Beyond the code itself, the stored freeze frame data reveals critical context: engine RPM, vehicle speed, coolant temperature, and load percentage at the moment of failure. This diagnostic snapshot helps pinpoint whether the problem occurred during specific driving conditions or across various scenarios.

Common Symptoms of P0747

Illuminated check engine or transmission warning light on the dashboard
Noticeable slipping between gear transitions, with delayed or incomplete shifts
Complete loss of forward or reverse movement in severe cases
Shuddering or vibration felt at highway speeds
Transmission locked into a single gear, commonly called limp-home mode
Harsh or erratic shift quality when the vehicle does move
Unusual noises from the transmission pan area during operation

What Causes P0747?

Contamination from carbon deposits, dirt, or corrosion jamming the solenoid mechanism (most frequent cause)
Welded relay contacts or shorted wiring keeping the solenoid circuit permanently energized
Worn or broken internal components within the pressure control solenoid assembly
Valve body wear or scoring that restricts hydraulic flow to the solenoid
Failed shift solenoid or pressure control solenoid requiring replacement
Low transmission fluid level or severely degraded fluid that cannot maintain proper pressure
Internal mechanical problems such as worn clutches or torque converter damage

How to Diagnose P0747

Connect an OBD2 scanner to confirm P0747 is stored in the transmission or powertrain control module, then save all freeze frame data for reference during the repair process.
Check for related diagnostic trouble codes—these often point to the underlying cause rather than the solenoid itself. Research manufacturer technical service bulletins for your specific make and model, as factory-issued fixes or software updates may apply.
Perform a thorough visual inspection of the wiring harness and connectors feeding the transmission control system, looking for damaged insulation, corrosion buildup, broken pins, or loose connections.
Use the scanner to command the pressure control solenoid on and off while monitoring the feedback signal, then physically remove and inspect the solenoid for binding, debris, or obvious wear.
Check transmission fluid level and condition—dark brown or burnt-smelling fluid indicates overheating and internal wear that may be contributing to the problem.
Read transmission-specific codes and monitor live data streams showing solenoid states, input/output shaft speeds, and hydraulic pressures to verify proper operation before and after repairs.
Clear the code and complete a full drive cycle that replicates the freeze frame conditions, then verify P0747 does not return.

Repair Options for P0747

Begin with the most affordable and common solutions before considering expensive component replacement. Valve body repair or replacement typically costs $700–$1,500, addressing the core hydraulic passages where solenoid issues often originate. If internal damage extends beyond the valve body, a transmission rebuild runs $2,500–$5,500, while complete transmission replacement may be necessary in worst-case scenarios. A transmission fluid service including filter replacement costs $150–$350 and can resolve solenoid performance issues caused by contamination. Replacing a failed shift solenoid generally runs $300–$800 depending on vehicle make and labor rates.

Total Cost to Fix P0747

Your actual repair expense hinges entirely on which component triggered P0747. At independent shop labor rates (parts and labor, USD), the most common fixes break down as follows: transmission fluid service $150–$350, shift solenoid replacement $300–$800, valve body repair or replacement $700–$1,500, and transmission rebuild or replacement $2,500–$5,500. Most P0747 diagnoses end up costing between $150 and $1,500 when addressed early. Confirming the root cause before purchasing parts prevents spending $2,500 on a new transmission when a $300 solenoid or $200 fluid service would have sufficed.

Can You Drive with P0747?

Caution applies here. If the transmission continues shifting without severe slipping or hesitation, short-distance driving to a repair facility poses limited risk. Avoid highway speeds and aggressive acceleration, as continued operation under load accelerates internal wear and can transform a $300 solenoid problem into a $3,000 transmission rebuild. P0747 is not typically an immediate stop-driving code, but delaying repairs increases the final bill with every additional mile driven.