Damaged, chafed or corroded wiring between the transmission control module and the solenoid; Poor connection at the transmission harness connector or internal gearbox connector (bent, loose or corroded pins); Pressure control solenoid A failing internally with an intermittent open or short circuit; Contaminated, degraded or low transmission fluid affecting the solenoid and valve body; Low or unstable system voltage from a weak battery or poor earth connection; Fault within the transmission control module or its driver circuit; Internal harness fault inside the transmission (model dependent).

P0749

Pressure Control Solenoid A Intermittent.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
7: AreaTransmission
49: FaultThe specific fault in that area

What it means

P0749 means the transmission control module has detected an intermittent fault in the electrical circuit of pressure control solenoid A, which regulates automatic transmission line pressure. The fault comes and goes, so the module saw a brief open circuit, short, or erratic signal rather than a constant failure. Which solenoid is 'A' and how it is wired depends on the make, model and transmission.

Symptoms

Harsh or delayed gear shifts that come and go
Gearbox briefly slipping or flaring between gears
Transmission stuck in a single gear (limp mode) at times
Gearbox warning light or malfunction indicator lamp on
Poor fuel economy or reduced performance
Symptoms that vary with temperature or road vibration

Possible causes

Damaged, chafed or corroded wiring between the transmission control module and the solenoidlikely
Poor connection at the transmission harness connector or internal gearbox connector (bent, loose or corroded pins)likely
Pressure control solenoid A failing internally with an intermittent open or short circuitlikely
Contaminated, degraded or low transmission fluid affecting the solenoid and valve bodypossible
Low or unstable system voltage from a weak battery or poor earth connectionpossible
Fault within the transmission control module or its driver circuitrare
Internal harness fault inside the transmission (model dependent)rare

How to diagnose

Read all stored and pending codes and freeze frame data to see when the fault occurred (gear, temperature, speed, voltage)
Check transmission fluid level and condition, following the manufacturer's procedure for your model as some gearboxes are sealed
Test battery condition and charging voltage, and check main earth connections
Inspect the transmission wiring and connectors for chafing, heat damage, fluid ingress, corrosion and bent or pushed-back pins
Wiggle-test the harness and connector with the engine running while monitoring solenoid current or commanded versus actual pressure on live data
Measure solenoid resistance and compare with the manufacturer's specification for your transmission
Check wiring continuity and insulation to earth and to supply between the module and the solenoid
Check for relevant technical service bulletins or software updates for your model before condemning the control module

How to fix

Repair or replace damaged wiring and renew faulty connectors or terminals
Clean and secure the connector, ensuring pins make good contact and seals are intact
Replace pressure control solenoid A if resistance or operation is out of specification
Correct fluid level, or change the fluid and filter if contaminated, using the specified fluid
Restore battery health and repair poor earth or charging faults
Repair or replace the control module, or apply an updated calibration, only where a fault or outdated software is confirmed

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but harsh shifts, slipping or limp mode can cause accelerated gearbox wear, so have it checked soon. Avoid heavy loads, towing and hard acceleration, and stop driving if slipping becomes severe.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.