aaaa logo

Member of Australian Automotive Aftermarket Association

PRTC Council Member

4WD Council Member

Latest News

MAP Sensors Testing

What a technician needs to know when testing the MAP sensor on a naturally aspirated intake system. (0 – 1 Bar).

As covered in detail in the previous MAP sensor article, we know that the MAP sensor converts the manifold pressure to a voltage or frequency output signal to assist the PCM in fuel and timing control but the information may also be utilised for the control of other engine systems.

Multiple engine conditions may cause the required MAP sensor signal to alter which affects engine fuelling and in turn performance and emission levels.

Typically Common:

  • Vacuum leaks
  • Exhaust restrictions.
  • Valve timing irregularities
  • Misfiring
  • Excessive engine wear plus other conditions.

The importance of thorough electrical testing.

In many cases, a DTC (fault code) may suggest that the MAP sensor may be potentially faulty but further testing confirmed the condition was the result of other variants.

In other cases, the MAP sensor may not set a DTC (fault code) unless severely out of range as the operating range is quite broad but the effect of a slight MAP signal variation may cause the PCM to alter engine fuel and timing control which can have an effect on engine performance and emissions. This may be evident during short- and long-term trim measurements when using a suitable scanner.

Note: A technician’s thought process must be flexible when interpreting test data during diagnosis.

Specific MAP sensor possible fault conditions or areas that may affect MAP signal that require attention for thorough electrical testing:

  • Supply Voltage to MAP sensor (reference voltage)
  • Ground circuit. (Generally, in PCM)
  • Signal circuit plausibility may be an issue.
  • Out of range (component error)

Engine backfiring, carbon build up and possible fluid build-up on some MAP sensors are typical causes of out of range or output signal plausibility failures.

Thorough MAP signal testing.

Typically, monitoring serial data information with a suitable scanner may be enough to guide the technician in the next stage required in the MAP sensor diagnostic or testing process.

With the use of a suitable manifold pressure gauge, (vacuum gauge) as live measurement to validate the serial data and ensure the sensor output information is accurate.

Further confirmation:
A suitable oscilloscope may also be utilised to monitor the electric profile of the pressure sensor output signal in real time.

Typical test procedure: (3 terminal MAP sensor)

  • MAP circuit plausibility.
  • Checking MAP values when No activity in the circuit. That is – Key On / Engine Off - KOEO).
    Monitoring the scan tool results should indicate Atmospheric pressure. (101Kpa = 1 Bar)
    Note: this would indicate that the “supply voltage”, “Ground circuit” and “MAP sensor plausibility” is acceptable and is received by the PCM.
  • Engine Running Tests (with scanner and vacuum gauge connected)
  • When the engine is initially started, the drop in manifold pressure can be monitored by the vacuum gauge when the engine idle speed has stabilised. (typically- approx. 38 Kpa or 20” mercury). This average pressure reading is typical of a normally aspirated engine (Non-Turbo) and should be stable with very little needle fluctuation. This pressure value can be verified by the scanner reading
    Note: the “cylinder fuel supply” control relies mainly on MAP and Coolant sensor output signals, so accuracy is essential for correct engine fuelling. Therefore, any DTC condition referring to fuelling problems / Trims would require thorough testing of the MAP sensor plausibility.
  • Utilising a suitable oscilloscope for MAP profile inspection and comprehensive testing.Note: Utilising the sensor ground reference directly, when connecting the oscilloscope, generally results in a clearer/ cleaner sensor profile image.

Initial Crank / Start monitoring expectations.

  • Quick response in profile change from crank to start condition.
  • A lot of clear activity.
  • Utilising high sample rate allows for monitoring detailed individual cylinder intake and accurate MAP sensor sensitivity.

Engine stabilised after starting.

  • Idle control systems stabilization process (on initial starting) can be monitored.

Wide Open Throttle test (snap acceleration)

Profile requirements:

  • Quick response on rise time of sensor from idle to full throttle (atmospheric pressure). This allows the monitoring of any blockage or contamination that would slow the rise time.

Note: The accelerator release results in a higher that idle vacuum profile resulting when throttle valve closes. The Idle stabilising profile can also be seen which can be used to monitor signs of any air leaks and any idle control system irregularities.

Engine switched OFF from Idle condition. (back to static “engine manifold” atmospheric pressure).

Note: a four terminal MAP sensor integrates an air intake temperature sensor that utilises the extra terminal.

Typical MAP sensor test data requirements to ensure sensor plausibility.

The Premier Auto Trade Sensor range includes 139 MAP Sensors (MAP) from the world’s leading manufacturers, covering almost 9 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