Faulty VSV 2 solenoid (open or shorted coil).; Damaged or disconnected vacuum hose connected to the VSV.; Corroded or loose electrical connector at the VSV.; Broken or chafed wires in the VSV 2 circuit (open or short to ground/power).; Failed engine control module (ECM) driver for the VSV circuit (rare).; Contamination or blockage in the vacuum passage controlled by the VSV.

DTC codes / Jaguar codes / P1237

P1237 · JaguarVSV 2 Circuit

Q: What does code P1237 mean?

VSV 2 Circuit. P1237 on a Jaguar indicates that the engine control module (ECM) has detected an electrical fault in the circuit for Vacuum Switching Valve 2 (VSV 2), which is a solenoid used to control vacuum flow to various engine systems. The ECM monitors the VSV 2 circuit for expected voltage or current and sets this code when the signal is out of range, typically indicating an open, short, or excessive resistance in the wiring or the solenoid itself.

P1237 on a Jaguar indicates that the engine control module (ECM) has detected an electrical fault in the circuit for Vacuum Switching Valve 2 (VSV 2), which is a solenoid used to control vacuum flow to various engine systems. The ECM monitors the VSV 2 circuit for expected voltage or current and sets this code when the signal is out of range, typically indicating an open, short, or excessive resistance in the wiring or the solenoid itself.

SystemPowertrain

Code typeJaguar specific

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms.
Rough idle or unstable engine speed due to improper vacuum control.
Poor acceleration or hesitation during driving.
Increased fuel consumption as the engine management system compensates.
In some cases, a slight hissing sound from a disconnected or leaking vacuum hose.
Intermittent operation of vacuum-operated accessories, such as the EVAP purge system or secondary air injection.

Common causes, most likely first

Faulty VSV 2 solenoid (open or shorted coil).
Damaged or disconnected vacuum hose connected to the VSV.
Corroded or loose electrical connector at the VSV.
Broken or chafed wires in the VSV 2 circuit (open or short to ground/power).
Failed engine control module (ECM) driver for the VSV circuit (rare).
Contamination or blockage in the vacuum passage controlled by the VSV.

How to diagnose and fix it

Verify the code with a Jaguar-specific scan tool and check for any related codes in other systems.
Inspect the VSV 2 electrical connector and wiring for corrosion, damage, or looseness; repair as needed.
Test the VSV 2 solenoid resistance with a multimeter and compare to the manufacturer's specification; replace if out of range.
Check the vacuum hoses connected to the VSV for cracks, disconnections, or blockages; replace or clean as necessary.
Using a wiring diagram, perform a continuity and voltage drop test on the VSV 2 circuit to rule out wiring faults.
If the circuit and solenoid test good, suspect the ECM; perform further diagnostics before replacement.
Clear the code and perform a road test to confirm the repair and ensure the code does not return.

Don't overlook the vacuum lines

A common oversight is replacing the VSV solenoid without checking the vacuum hoses, which can be cracked or disconnected and cause the same symptoms.
The VSV 2 circuit may be affected by a shared power or ground circuit with other solenoids, so a fault elsewhere can set this code.
In some Jaguar models, the VSV 2 is part of the EVAP system, and a faulty gas cap or purge valve can indirectly trigger this code.
A visual inspection of the VSV and its connector often reveals the problem, such as a broken wire or corroded pins, before any electrical testing.
The ECM driver for the VSV circuit is robust, but a shorted solenoid can damage it; always check the solenoid before replacing the ECM.

Can I keep driving with P1237?

You can generally continue driving with this code, but avoid aggressive acceleration or heavy loads until repaired, as the fault may affect engine performance and emissions. Have the vehicle diagnosed soon to prevent potential damage to other components.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

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