aaaa logo

Member of Australian Automotive Aftermarket Association

PRTC Council Member

4WD Council Member

Latest News

Testing Electric Valve Solenoids (EVS)

What technicians need to know when carrying out diagnosis or testing on an EVS unit or related circuit fault.

As mentioned in the previous EVS article these units are fitted to multiple control systems in the modern vehicle and may be known as:

  • Electro Pneumatic valve
  • Boost Control Solenoid Valve.
  • Vacuum Solenoid Valve (VSV)
  • Vacuum Switching Valve
  • Vacuum Control Solenoid

There are of course multiple causes of failure in the specific systems that the technician is required to investigate, but before any tests can be carried out, the method of switching control of the EVS is necessary so the correct testing procedure can be performed on the unit and related circuit.

Please refer to previous article as above for EVS types and mechanical operation.

Typical common EVS switching circuit.

Ground switching control in PCM. (Ground side switched – most common)

Depending on the system circuit, a constant Battery power supply is generally directed to one of the EVS terminals. The other EVS terminal is connected to the PCM where it is (control) grounded.

Checking the voltage at the harness terminals with the connector disconnected, can quickly identify the specific EVS terminals.

  • The power supply may always be present with ignition ON or OFF or with ignition ON only.
  • The Ground switching control may utilise a 5V Bias voltage that can be checked with harness disconnected. (voltage from the PCM with ignition ON)

For other tests reconnect the harness connector.

To determine the type of circuit and/or to carry out an electrical test procedure:

  • With harness connected and power supplied to EVS but not activated, back probe both terminals individually and monitor the results. Equal Battery Voltage should be evident on each terminal if circuit is functioning correctly (with EVS not activated)

Possible alternative voltage results caused by faults in the EVS or circuit:

  • No power supply to EVS (generates from relay or fuse or possibly PCM on some systems)
  • A battery power supply at the EVS terminal but Zero volts at the ground switching control terminals would indicate an open circuit in the EVS windings or related harness. (A short to ground wire from the EVS to the PCM would also result in a very low voltage but the EVS would be continually fully activated)
  • Intermittent problems may also be common where corroded or loose terminals are evident.
  • When activated, the PCM should pulse ground the EVS switching terminal.
    This can be accurately tested with an oscilloscope during the activation process which may be achieved on request with the use of a suitable scanner. (ensure EVS power supply is correct and the EVS unit is not faulty).

Note:  If “no EVS pulse” is evident during an activation request, the use of a conventional incandescent type test light may be used to activate the EVS circuit. Contacting the ground control terminal should result in an audible activation sound. If an audible sound is evident then further tests are required at the PCM area to determine the cause for no PCM switching. (test light is acting as a safe ground for the circuit switching).

Note:   A typical normal operating current through an EVS is approx. 0.370 Amps. A conventional (incandescent) type test light operating current is approx. 0.186 Amps and is quite acceptable for a test tool for this purpose as it allows sufficient current to activate the EVS.

An LED test light is not suitable to activate the EVS as there is insufficient current flow through the LED assembly and can only be used for signal monitoring.

Typical vacuum flow circuit test method for EVS.

Note: it is important to ensure all vacuum hoses are connected correctly/ tightly fitted and not leaking prior to any vacuum related EVS fault tests.

Typical faults may be intermittent or hard fault:

  • EVS units stuck in the open condition when activated or de-activated.
  • EVS units stuck in the closed condition when activated or de-activated.

Note: The open or closed conditions may be due to electrical faults or unit internally jammed. It is important to ensure the actuator and related system mechanism is functioning correctly to prevent misdiagnosis.

Electro-Pneumatic Vacuum pump valve

Using the vacuum pump can verily if the valve is sealed or leaking when not activated and if the valve opens when the solenoid is activated. Solenoid resistance can also be tested with an ohm meter.

The Premier Auto Trade Emission range includes more than 40 Electric Valve Solenoids (EVS) from the world’s leading manufacturers, covering over 2.7 million vehicle applications in Australia and NZ.

When you supply and fit products from Premier Auto Trade you can expect a product designed and tested to the vehicle manufacturer’s specifications offering OE form, fit and function. Premier Auto Trade distributes products throughout Australia via a network of specialised resellers and leading automotive groups.


Latest News

Tech Tips - Wheel Speed Sensors (WSS)

Positive Crankcase Ventilation (PCV) and Oil Separators

Common Rail Diesel Pumps (HDP)

Exhaust Gas Temperature Sensor (EGT)

Hose Clamps

MAP Sensors (Manifold Absolute Pressure)

Electric Water Pumps

Pulse Width Modulation (PWM)

Mass Air Flow Sensors (Hot Wire/Film)

Petrol Fuel Injector Replacement

Electronic Throttle Bodies (TBO)

Dual Petrol Injection Systems – Technical Tip

Wheel Speed Sensors – More than just ABS

PAT Expands Emission Sensor Range

PAT Racing & Performance Injector Range Upgrade

Coils ain’t Coils!


Oil Level and Oil Temperature Sensors Operation

Failed Air Temperature Sensors Symptoms

MAP Sensors Testing

TI Automotive Mustang Performance Pump

New ICON SERIES Hose Clamp Range

New Premium Sensors Ranges

Relay problems on vehicle

Test Equipment and Tools

Fuel Rail Sensors (FRS)

Failing Secondary Ignition

Testing Electric Fuel Pumps

Performance Fuel Rails and Filters

Testing CAM Angle Sensors (CAM)

Testing Electric Valve Solenoids (EVS)

Electronic Throttle Bodies

Performance Fuel Cells & Surge Tanks

Fault Finding Fuel Pressure Regulators (FPR)

Testing Variable Camshaft Actuators (VCA)

Testing Accelerator Pedal Position Sensors (APS)

Diagnosing Crank Angle Sensors (CAS)

Performance Regulators and Gauges

Differentiating Wheel Speed Sensors (WSS)

Mass Air Flow Sensors - Hot Film

Mechanical Fuel Pumps (MFP)

ICON Series Hoses

Particulate Matter Sensors (PMS)

Performance Fuel Injectors

Fuel Injectors (GDI)

DENSO Spark Plugs

Performance Fuel Pumps

Cooling Fan Switches (CFS)

Water Temperature Sensors (WTS)

Reverse Light Switches

Oil Temperature Sensors (OTS)

BMC Air Filters

Flasher Cans

Exhaust Pressure Sensors (EPS)

Power Steering Switches

Coolant Temperature Sensors (CTS)

Variable Intake Manifolds (VIM) and Intake Control Valves (ICV)

Oil Level Sensors (OLS)

Throttle Position Sensors (TPS)

Air Temperature Sensors (ATS)

Ignition – Condensers, Contact Sets, Distributor Caps and Rotors

Fuel System Accessories (FSA)

MAP Sensors (MAP)

Relays (REL)

HALL Sensors and Pickups (HAL)

Fuel Rail Sensors (FRS)

Speed Sensors (SPS)

New ICON Series Fuel Pump Range

New ICON Series Hose Range

Performance Range Increase Continues

PAT Oxygen Sensor Range Expands

PAT Expands Automotive Aftermarket Presence

Equipment and Tools

Electric Fuel Pumps (EFP)

Electric Valve Solenoids (EVS)

CAM Angle Sensors (CAM)

Ignition Modules (MOD)

Injector Service Components

Exhaust Gas Temperature Sensors (EGT)

Throttle Bodies

Knock Sensors

Ignition Coils

Fuel Injectors (Petrol)

Variable Camshaft Actuators (VCA) Oil control Valves

Accelerator Pedal Position Sensors (APPS)

Exhaust Gas Recirculation Valves (EGR)

Relocation of Sydney Distribution Centre

Wheel Speed Sensors (WSS)

High Tension - Ignition Lead Sets (ILS)

Suction Control Valves (SCV)

Mass Air Flow (MAF) Sensors

Crank Angle Sensors (CAS)

Fuel Pressure Regulators (FPR)

Oil Pressure Sensors

Exhaust Gas Oxygen Sensors

Shedding Light on Stop Light Switches

Ignition Distributors

Common Rail Diesel (CRD) Fuel Injectors

Idle Speed Control

New Distribution Centre Opening in ADELAIDE

New Distribution Centres Opening in PERTH and DARWIN

New Fuel Catalogue from Premier Auto Trade

BMC 4WD Air Filters Range Expands

New MVP Fuel Injector Range

PAT Developing Programs on Demand

New Premium Packaging for PAT

New Product Ranges Released By PAT

PlusQuip Test Equipment Range Expands

New Raceworks Catalogue

New Exhaust Gas Temperature Sensors

New Trade Catalogues from Premier Auto Trade

New Distribution Centre Opening in Adelaide

More European Parts from Premier Auto Trade

New PlusQuip Fuse Current Tester

PAT Pumped up!

Coils ain't Coils!

New PlusQuip Electronic EGR, Throttle Body, and Actuator Tester

New breed of High Performance products!

New Ignition Coil and Lead Set Kits

Wheel Speed Sensor Program Launched

Premier Ignition Lead Program Launch

Ignition Coils - Coils ain't Coils!

PlusQuip Battery Testers Launch

Premier Auto Trade Supporting Local Racing

Oval Trumpet Airbox (OTA) for 4WD applications from BMC Air Filters

BMC Air Filters NOW AVAILABLE from Premier Auto Trade

Premier Ignition Coils

MAP-013 and KNS-021 Now Back in Stock

BMC Air Filter partners with Premier Auto Trade

Premier Auto Trade opens South Australian Distribution Centre

Direct Fit Oxygen Sensor Range Hits 700

Automotive Electro-Mechanical Relays Types / Faults / Diagnosis

PlusQuip Tools and Equipment Launch

PlusQuip Fuel Line Repair Kit

PlusQuip Fuel Injector Service Kit

E85 High Performance with Premier Auto Trade

Testing EGR Systems (Pt 2)

New Delphi Fuel Module and Ignition Coil Range

Fuel Injector Service Components from Premier Auto Trade

Older News...

   privacy statement   terms of use   terms and conditions   sitemap   news  

© PremierAutoTrade