P2738 — Pressure Control Solenoid "F" Control Circuit Low

P2738 — Pressure Control Solenoid "F" Control Circuit Low. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: faulty transmission speed sensor, wiring or connector faults in the valve body harness, low or degraded transmission fluid.

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

  1. Read the code and freeze frame Connect an OBD2 scanner, confirm P2738 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
  2. 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.
  3. Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the automatic transmission control for damage, corrosion, chafing or poor contact.
  4. Subsystem check Check for supply voltage at the pressure control solenoid "F" control connector first; then measure resistance from the signal wire to ground — near-zero ohms confirms a short to ground in the harness.
  5. Subsystem check Check transmission fluid level and condition — dark, burnt fluid points to internal wear.
  6. Subsystem check Read transmission-specific codes and live data (solenoid states, input/output speed) with a capable scanner.
  7. Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2738 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P2738 (parts and labor, USD, independent shop rates): Valve body repair or replacement: $700–$1,500; Transmission rebuild or replacement: $2,500–$5,500; Replace a shift solenoid: $300–$800; Transmission fluid service: $150–$350. Overall, fixing P2738 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

Is it safe to drive with P2738?

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 does OBD2 code P2738 mean?

P2738 — Pressure Control Solenoid "F" Control Circuit Low. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: faulty transmission speed sensor, wiring or connector faults in the valve body harness, low or degraded transmission fluid.

What is the most common cause of P2738?

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

How do I diagnose P2738 myself?

Start with a scan: confirm P2738, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the pressure control solenoid "F" control, and verify the suspect component against live data before buying parts.

How much does it cost to fix P2738?

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

What does P2738 mean?

P2738 (Pressure Control Solenoid "F" Control Circuit Low) is stored when self-diagnostics detect abnormal readings or behaviour of the automatic transmission control. It belongs to the powertrain (engine/transmission) category.

“Circuit low” means the voltage on the pressure control solenoid "F" control circuit stays below the expected minimum — close to ground. The usual physical reasons are a short to ground, a chafed wire touching metal, a missing supply voltage, or a failed component dragging the signal down.

The module monitors this system continuously while driving. When readings fall outside the expected range for a defined number of drive cycles, it stores P2738 and switches on the warning light. Freeze frame data saved with the code shows the exact conditions — rpm, load, temperature, speed — at the moment the fault was detected, which is the best starting point for diagnosis.

What causes P2738?

  • signal wire shorted to ground (chafed insulation)
  • failed pressure control solenoid "F" control pulling the signal low
  • missing supply voltage to the pressure control solenoid "F" control
  • faulty transmission speed sensor
  • low or degraded transmission fluid
  • wiring or connector faults in the valve body harness
  • internal mechanical wear (clutches, torque converter)
  • failed shift or pressure control solenoid
  • valve body wear

Common symptoms of P2738

  • harsh or delayed shifting
  • Check Engine or transmission warning light on
  • shuddering at highway speed
  • transmission stuck in one gear (limp mode)
  • slipping between gears

How to diagnose P2738

  1. Connect an OBD2 scanner, confirm P2738 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
  2. 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.
  3. Visually inspect the wiring harness and connectors related to the automatic transmission control for damage, corrosion, chafing or poor contact.
  4. Check for supply voltage at the pressure control solenoid "F" control connector first; then measure resistance from the signal wire to ground — near-zero ohms confirms a short to ground in the harness.
  5. Check transmission fluid level and condition — dark, burnt fluid points to internal wear.
  6. Read transmission-specific codes and live data (solenoid states, input/output speed) with a capable scanner.
  7. Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2738 does not return.

How to fix P2738

Start with the cheapest and most common causes before replacing expensive parts:

  • Valve body repair or replacement — $700–$1,500
  • Transmission rebuild or replacement — $2,500–$5,500
  • Replace a shift solenoid — $300–$800
  • Transmission fluid service — $150–$350

How much does it cost to fix P2738?

Repair cost depends on which component actually failed. Typical scenarios for P2738 (parts and labor, USD, independent shop rates):

  • Valve body repair or replacement: $700–$1,500
  • Transmission rebuild or replacement: $2,500–$5,500
  • Replace a shift solenoid: $300–$800
  • Transmission fluid service: $150–$350

Overall, fixing P2738 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.

Can you drive with P2738?

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.

Related OBD2 codes