Faulty pressure regulator solenoid (open or shorted coil); Damaged or corroded wiring harness to the solenoid; Poor electrical connection at the solenoid or TCM connector; Internal transmission valve body wear or debris blocking the regulator valve; TCM software glitch or internal fault; Low transmission fluid level or degraded fluid causing pressure irregularities

DTC codes / Jaguar codes / P1745

P1745 · JaguarPressure Regulator 1

Q: What does code P1745 mean?

Pressure Regulator 1. P1745 on a Jaguar indicates that the Transmission Control Module (TCM) has detected an electrical fault in the pressure regulator valve circuit, often the solenoid that controls line pressure inside the automatic gearbox. The computer monitors the circuit for open, short, or out-of-range resistance and sets this code when the signal does not match expected values.

P1745 on a Jaguar indicates that the Transmission Control Module (TCM) has detected an electrical fault in the pressure regulator valve circuit, often the solenoid that controls line pressure inside the automatic gearbox. The computer monitors the circuit for open, short, or out-of-range resistance and sets this code when the signal does not match expected values.

SystemPowertrain

Code typeJaguar specific

SeverityMedium

Fix difficultyIntermediate

AreaTransmission

Symptoms you may notice

Harsh or delayed gear shifts, especially when engaging drive or reverse
Transmission stuck in a single gear or failsafe mode
Illuminated check engine light or transmission warning message on the dash
Slipping gears or a flare in engine speed during acceleration
Often no symptoms besides the warning light, with normal driving behavior

Common causes, most likely first

Faulty pressure regulator solenoid (open or shorted coil)
Damaged or corroded wiring harness to the solenoid
Poor electrical connection at the solenoid or TCM connector
Internal transmission valve body wear or debris blocking the regulator valve
TCM software glitch or internal fault
Low transmission fluid level or degraded fluid causing pressure irregularities

How to diagnose and fix it

Check transmission fluid level and condition; top up or replace if contaminated
Inspect the solenoid wiring harness for chafing, corrosion, or loose connectors
Measure resistance of the pressure regulator solenoid and compare to specification
Perform a voltage drop test on the solenoid circuit under load
Replace the pressure regulator solenoid if resistance is out of range
Repair or replace damaged wiring or connectors as needed
Clear the code and perform a transmission adaptation reset and road test

Before replacing the pressure regulator solenoid

A low or dirty transmission fluid can mimic a failed pressure regulator by causing erratic pressure readings, so always verify fluid condition first.
The solenoid circuit often fails at the connector pins due to water ingress, not the solenoid itself, so inspect the plug before condemning the part.
On some Jaguar models, a software update for the TCM addresses false P1745 triggers without any hardware fault.
A sticking valve body spool can cause the same pressure deviation as an electrical solenoid failure, requiring valve body inspection or replacement.
After replacing the solenoid, a transmission adaptation reset is essential; otherwise the TCM may continue to set the code due to learned values.

Can I keep driving with P1745?

You can usually drive the car to a workshop if the transmission still shifts reasonably and the warning light is steady, but avoid heavy acceleration or towing. If the gearbox enters limp mode or shifts become severely harsh, stop driving and seek professional diagnosis to prevent further damage.

Tools that help

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Guidance is general and written for Jaguar vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.