Category: INFO

Crankshaft Position Sensor(CKPS)

Crankshaft position sensor: how it works, symptoms, problems, testing

The crankshaft position sensor measures the rotation speed (RPMs) and the precise position of the engine crankshaft. Without a crankshaft position sensor the engine wouldn’t start. In some cars, the sensor is installed close to the main pulley (harmonic balancer) like in this Ford in the photo. In other cars, the sensor could be installed at the transmission bell housing, or in the engine cylinder block, as in the photo below. In the technical literature, the crankshaft position sensor is abbreviated to CKP.

How the crankshaft position sensor works

The crankshaft position sensor is positioned so that teeth on the reluctor ring attached to the crankshaft pass close to the sensor tip. The reluctor ring has one or more teeth missing to provide the engine computer (PCM) with the reference point to the crankshaft position.

As the crankshaft rotates, the sensor produces a pulsed voltage signal, where each pulse corresponds to the tooth on the reluctor ring. The photo below shows the actual signal from the crankshaft position sensor with the engine idling. In this vehicle, the reluctor ring is made with two missing teeth, as you can notice on the graph.

The PCM uses the signal from the crankshaft position sensor to determine at what time to produce the spark and in which cylinder. The signal from the crankshaft position is also used to monitor if any of the cylinders misfires. If the signal from the sensor is missing, there will be no spark and fuel injectors won’t operate.

Crankshaft position sensor signal on the oscilloscope screen.

The two most common types are the magnetic sensors with a pick-up coil that produce A/C voltage and the Hall-effect sensors that produce a digital square wave signal as in the photo above. Modern cars use the Hall-effect sensors. A pick-up coil type sensor has a two-pin connector. The Hall-effect sensor has a three-pin connector (reference voltage, ground and signal).

Symptoms of a failing crankshaft position sensor

A failing sensor can cause intermittent problems: a car may cut out or stall randomly, but then restart with no problems. The engine might have troubles starting in wet weather, but starts OK after. Sometimes you might see the RPM gauge behaving erratically. In some cases, a failing sensor can cause long crank time before the engine starts. If the sensor is bad, the engine will crank but won’t start.

Crankshaft position sensor problems

The most common OBDII code related to the crankshaft position sensor is P0335 – Crankshaft Position Sensor “A” Circuit. In some cars (e.g. Mercedes-Benz, Nissan, Chevy, Hyundai, Kia) this code is often caused by a failed sensor itself, although there could be other reasons, such as wiring or connector issues, damaged reluctor ring, etc.

In some cars, the intermittent stalling can also be caused by a problem with the crankshaft position sensor wiring. For example, if if the sensor wires are not secured properly, they could rub against some metal part and short out, which can cause intermittent stalling.

The Chrysler bulletin 09-004-07 describes a problem with some 2005-2007 Jeep and Chrysler models where a failed crankshaft position sensor can cause a no-start problem. The sensor will need to be replaced with an updated part to correct the problem.

Another Chrysler bulletin 18-024-10 for some 2008-2010 Chrysler, Dodge and Jeep vehicles mentions a problem where the code P0339 – Crankshaft Position Sensor Intermittent can be caused by improper gap or a bad flexplate.

Failures of the crankshaft position sensor were common in some 90’s GM cars. One of the symptoms was stalling when the engine is hot. Replacing the crankshaft position sensor usually solved the problem.

How the crankshaft position sensor is tested

Whenever there is a suspicion that the problem might be caused by a crankshaft position sensor or if there is a related trouble code, the sensor must be visually inspected for cracks, loose or corroded connector pins or other obvious damage. The proper gap between the tip of the sensor and the reluctor ring is also very important.

The correct testing procedure can be found in the service manual. 

For the pick-up coil type sensors, the testing procedure includes checking the resistance.For example, for the 2008 Ford Escape, the resistance of the crankshaft position sensor (CKP) should be between 250-1,000 ohms, according to Autozone. We measured 285.6 ohms (in the photo) which is within specifications. If the resistance is lower or higher than specified, the sensor must be replaced.

For the Hall-type sensors, the reference voltage (typically +5V) and the ground signal must be tested. The most accurate way to test a crankshaft position sensor is checking the sensor signal with an oscilloscope.

Sometimes, the sensor may have an intermittent fault that is not present during testing. In this case checking for Technical Service Bulletins (TSBs) and researching common problems may help. 

Signal from the crankshaft position sensor is represented as “Engine RPM” in an OBDII scan tool.The crankshaft position sensor can be checked with a scan tool. It shows the sensor signal as “Engine RPM” or “Engine speed.” When this could be helpful? If a car stalls intermittently, monitoring the sensor signal can provide the answer: if the sensor signal suddenly drops to zero, and then comes back it means either there is a problem inside the sensor or with the sensor wiring or connector.

If the sensor works properly, the RPM signal should drop or rise gradually. as in this photo. We have tested the crankshaft position sensor in this car with an OBDII “Torque” app on the mobile phone.

Camshaft Position Sensor(CMPS)


Modern engines are impressive machines made up of individual parts interacting with precision, which is necessary for top performance, efficiency and safety. Without it, you don’t get much. Many components are responsible for keeping everything humming along, but an important one is the camshaft sensor. But, what is a camshaft position sensor, and why is it so important?


Camshaft Position Sensor(CMPS)

Gasoline combustion engines have very specific needs for air, fuel and spark in order to run as designed. These three elements must be available at the right time and in the right quantity for efficient combustion. If the ti

ming is too far off or if one piece is missing, you may not get any combustion.

An engine’s precision is enabled by a system of car sensors that monitor components and conditions and interface with the electronic control unit (ECU), the vehicle’s main computer. The ECU receives input from sensors and makes an immediate call based on programming. It then sends a signal to an actuator that changes or maintains a condition, including air, fuel and spark, to reflect information from the sensors. If there is a mechanical problem and one of the components is faulty or broken, the sensors will let the ECU know to either adjust or alert you.


The camshaft and crankshaft are two of these important components. The camshaft controls the position of the inlet and exhaust valves, while the crankshaft controls the location of the pistons themselves.

If a camshaft controls those valves, what is a camshaft position sensor, and why is it necessary? Camshaft position sensors monitor the camshaft’s position and send information to the ECU about when each valve is open on a particular cylinder. They work closely with crankshaft position sensors to paint a more complete picture for the ECU.

Together, the information from these two sensors shows when a piston is at the top center for a potential intake stroke and confirms that the valves are aligned to deliver air and fuel. Basically, camshaft and crankshaft position sensors work together to show the computer when the conditions are right for intake, compression, combustion and exhaust.


A camshaft sensor problem will usually trigger the check engine light. From there, you can do a diagnostic scan to suss out a camshaft issue, but it won’t tell you whether the problem is the sensor or the component it’s monitoring. That will take further digging.

You may additionally notice problems with drivability. The engine may stutter or surge, use more fuel than usual, have poor acceleration, stall or not even start at all. These are all signs of a problem with the camshaft, but again, you’ll need to take a closer look. A failing sensor or glitchy ECU can also cause these problems, and sensors are much easier to change than camshafts, so have a mechanic check it out if you’re not sure.

Your ECU should let you know when something is amiss, but if you notice problems, get it checked out sooner rather than later. Camshaft issues only get worse with time and can cause bigger engine problems down the road.

Symptoms of Camshaft Position Sensor

Since the camshaft position sensor plays an important role, a number of problems can arise when it malfunctions. Due to being overworked or an accident, the camshaft position sensor may fail or may wear out.

There are a few warning symptoms that arise before your camshaft position sensor has completely failed and the engine shuts down, which needs to be replaced immediately.

  1. Poor fuel economy
  2. Check engine light comes ON
  3. Ignition problems
  4. Poor transmission shifting
  5. Stalling of engine
  6. Poor acceleration
  7. High fuel consumption
  8. Engine misfire
  9. Gas smell
  10. Rough Idling
  11. Engine won’t start

Diesel Nitrogen Oxide (NOx) Sensors

A High Failure Part That’s Required for Emissions Regulations

NOx sensors monitor the level of nitrogen oxide being emitted by a diesel vehicle to ensure compliance with emissions regulations. Most engines feature two NOx sensors: an upstream and downstream sensor. Common causes of failure include soot buildup on the sensor, ECU water intrusion, and/or damage to the cable, which will cause the check engine light to illuminate. To provide quality and coverage for this important and growing diesel category, we’re proud to introduce a line of Diesel NOx Sensors.

About NOx Sensors

Below is a diagram of a generic Selective Catalytic Reduction (SCR) system used on light-duty diesel passenger trucks. The assembly uses two NOx sensors: the first sensor (referred to as NOx sensor 1) is located near the turbo downpipe and measures engine out NOx. The second sensor (referred to as NOx sensor 2) measures NOx levels exiting the SCR catalyst.

The SCR assembly contains a catalyst brick that requires DEF, or diesel exhaust fluid, for activation. A PCM controlled pump and doser valve are used to meter DEF into the exhaust system upstream of the SCR brick. With the exhaust heat, the DEF will decompose into ammonia and carbon dioxide.

If too much DEF is injected into the exhaust, the SCR brick can become saturated with ammonia and some of it will exit the SCR assembly. This is called “ammonia slip”. To a NOx sensor, ammonia and NOx look the same. Ammonia slip will cause the downstream NOx sensor to report an incorrect amount of NOx in the exhaust stream.

How do you know if the NOx Sensor is reporting NOx levels correctly?

While addressing SCR codes concerning DEF quality, NOx sensor failure, or SCR efficiency, it may be necessary to “burn out” saturated SCR bricks and run the onboard diagnostic again. This can be accomplished by performing a manual DPF regen. The heat produced during the manual regen will remove ammonia from the SCR bricks and allow for a more accurate onboard SCR system diagnostic.

NOx Sensor Repair Tips

Diesel NOx Sensors feature complex technology. Here are some repair tips to keep in mind: 

  • A degraded doser valve (DEF injector) may set NOx DTCs
  • Be sure to test the doser valve before replacing NOx sensors
  • After replacing a NOx sensor, be sure to check service information for any reset procedures
  • NOx sensors can’t tell the difference between NOx and ammonia
  • Performing a DPF regen will release ammonia from the SCR catalyst

Gas Pressure Sensor


Gas pressure sensors can be used to gauge altitude in aircraft, rockets or balloons. They’re frequently used in automotive design, from optimising engine function and controlling emissions to monitoring pressures in tyres and airbags, and even controlling inflatable air bolsters in dynamic seats.

In industrial settings, they can be used to measure the speed with which gas is flowing (sometimes known as ‘impact pressure’), to confirm that suction is present, to manage source pressures or to test for leaks.

Measurement options

Gas pressure sensors are designed (or can be configured) to measure gas pressure in different ways.

  • Gauge pressure is measured in relation to the surrounding atmospheric pressure. Atmospheric pressure is around 100kPa (14.7 PSI) at sea level. The sensor built into air pumps for tyres measures pressure in this way, showing the air pressure inside the tyre in relation to the local atmospheric pressure. A reading of zero indicates the pressures are equal inside and out.
  • sealed gas pressure sensor is similar to a gauge gas pressure sensor but has been pre-calibrated to measure gas pressure in relation to sea-level atmospheric pressure. So its readings won’t change if the unit is taken to a different altitude or location.
  • Vacuum pressure is the measure of the negative difference between the gas pressure at a given location and atmospheric pressure.
  • Absolute gas pressure is measured from zero, or a perfect vacuum (0 PSI). Again, unlike gauge pressure, this isn’t affected by the conditions around the unit, which can vary with changes in altitude and other factors.
  • Differential pressure is the difference between two gas pressures – for example, those in two gas hoses connected to the sensor. As with gauge pressure, the sensor may be able to measure changes of gas pressure in either direction (that is, positive or negative differences).

Beyond the different types of measurement, some gas pressure sensors are also designed to measure rapid pressure changes in dynamic environments, such as combustion pressure in an engine cylinder or a gas turbine.


Gas pressure sensors are transducers: they generate an electrical signal in proportion to the pressure they measure. This allows pressure to be monitored by microprocessors, programmable controllers, computers and other electronic devices connected to the sensor.

Some gas pressure sensors are analogue, providing pressure feedback in the form of an electrical current. There are also digital sensors, which provide a digital value for gas pressure, and sensors that provide other types of feedback, such as optic, visual or auditory signals. The most commonly used technology in analogue gas pressure sensors is the piezoresistive strain gauge, which uses the principle of piezoresistance.

A cross-section of a semiconductor distortion gauge,
as used in many gas pressure sensors

The sensor is based around a diaphragm made from monocrystalline silicon, polysilicon thin film, bonded metal foil, thick film or sputtered thin film. The diaphragm acts as a semiconductor distortion gauge: when gas presses on it, it is bent out of shape, which distorts the crystalline structure of the material. This, in turn, changes the electrical resistance of the diaphragm, allowing the sensor to reflect changes in pressure in the form of a change in current (see diagram below).

Other, less commonly used, technologies for gas pressure sensors include capacitance (similar to piezoresistance, but the capacitance of the material changes), electromagnetic, piezoelectric (for changes in pressure only), optical and potentiometric.

Some electronic sensors use other properties, such as density, ionisation or thermal conductivity, to infer the pressure of a gas rather than measuring it directly.

A resonant sensor uses changes in resonant frequency (the frequency at which a gas vibrates most readily) to measure changes in gas density caused by pressure. The sensing element can be made from vibrating wire, a vibrating cylinder, quartz or silicon.

Ionisation sensors measure gas pressure by monitoring the flow of charged gas particles (ions), as it varies as a result of density changes. Examples of ionisation sensors include hot-cathode and cold-cathode gauges.

Thermal sensors use changes in the thermal conductivity of a gas (how readily it conducts heat) to measure pressure. An example is the Pirani gauge, which features a heated metal filament suspended in a tube and measures the heat lost from the filament to the surrounding gas.

In digital gas pressure sensors, a silicon chip converts the current through the semiconductor distortion gauge into a numerical reading, and the data is then passed out of the unit via a process connector. This can then be monitored and/or stored by a computer or other electronic monitoring device.

In recent years, wireless pressure sensors have been introduced. These advanced sensors  can be controlled remotely, which allows them to be used for applications where wired connections wouldn’t be possible. They are usually battery-powered, making them completely self-contained and self-sufficient until the battery needs replacing. They typically offer more customisation and control options than standard sensors, and some allow settings such as high and low limits to be altered while the unit is in operation.

Some wireless sensors can connect to mobile devices such as smartphones, which can monitor, collect and store data from the sensor, carrying out functions which previously required a computer.

Options and specifications

A wide range of gas pressure sensors is available. They vary in terms of application suitability, cost, technology used, physical dimensions, fittings, process connectors and manufacturing materials used.

Gas pressure sensors normally have a working range defined in kilopascal (kPa), atmospheres (atm) or millimetres of mercury (Hg). They’ll also have an accuracy rating. For example, a sensor might have a working range of 0–210kPa, with accuracy of ±4kPa.

They may come with a stated response time, which reflects how long it takes them to provide a pressure reading – for example, 10ms.

And they typically have a temperature range of operation, since the sensitivity of a pressure gauge can be affected by temperature.

Diesel Particulate Filter(DPF) Differential Pressure Sensor

diesel particulate filter (DPF) differential pressure sensor measures exhaust backpressure and signals when the power-train control module (PCM) should begin a regeneration process to clear the filter of diesel particulate matter (DPM), or soot. The DPF differential pressure sensor plays an important role in keeping the DPF functioning properly. A clogged DPF is not only a costly repair, but it can have catastrophic consequences to your diesel engine as well. To understand how the DPF differential pressure sensor works, why it fails, and how to replace it when it does, let’s briefly discuss the DPF.

Delphi Technologies DPF sensor

What is the DPF and how does it work?

As stringent emissions regulations increase to reduce emissions, diesel engines use an EGR valve to reduce NOx emissions and a DPF to remove soot from diesel exhaust. Installed near the beginning of the exhaust system, the wall flow design of the DPF traps on average 85% of the soot coming from the engine, and in certain conditions can even attain 100% efficiency. To keep the filter from clogging, the engine initiates a regeneration process by injecting fuel into the exhaust system. The injected fuel will raise the temperature of the DPF to 600 °C (or 1112°F) so the obstructing soot can burn off by converting it into ash. For some vehicles, PCM relies on data from the DPF differential pressure sensor to initiate the DPF regeneration process.

How does a DPF differential pressure sensor work?

The DPF differential pressure sensor is usually mounted in the engine compartment to protect it from heat. The sensor is connected to the engine control unit (ECU) by an electrical connector and connected to the DPF via two silicon hoses. One hose connects before (upstream) the DPF, the other connects after (downstream) the filter. By measuring and comparing the difference in pressure of the exhaust gas before and after the filter, the sensor can estimate the amount of DPM that is trapped in the filter and signal the PCM to start the DPF regeneration process. 

Why do DPF differential pressure sensors fail?

As with any electrical sensor in an engine, wires to the ECU can be damaged from harsh vibrations or crack and melt from extreme heat. And just like the DPF, the sensor hoses can also become clogged from soot in the exhaust. When diesel particulate matter blocks one or both of these airways to the sensor, the sensor can no longer determine pressure changes accurately, which can result in catastrophic damage to the DPF and ultimately the engine. 

What to look out for in a failing DPF differential pressure sensor

When the DPF differential pressure sensor stops signaling the PCM to regenerate, the DPF can become completely obstructed by contaminates and fail. Here are some signs that indicate the DPF is not regenerating properly due to the DPF sensor failing:

  • Poor engine performance 
  • Poor fuel economy
  • High engine temperatures 
  • High transmission temperatures
  • An increase in black smoke (soot) from the exhaust 
  • Check engine light

When the DPF fails, exhaust gases can not be fully purged as backpressure pushes exhaust back into the combustion chamber causing DPM or soot to mix with the engine oil. Soot is abrasive and when mixed with oil, will cause premature wear to the engine bearings. The fuel that should be escaping through the exhaust during regeneration will also only partially burn. This leftover fuel will then wash away the protective oil film on internal engine components and cause catastrophic failure. 

A DPF pressure sensor is vital to the longevity of the DPF, and if the DPF becomes completely obstructed, the regeneration process will not fix it. It will need to either be removed and professionally cleaned or replaced, both options on average costing thousands of dollars. Much more than the cost of diagnosing and replacing a faulty sensor before it’s too late.

Manifold Absolute Pressure MAP sensor

Making sense of your sensors: MAP sensor

Typically found in fuel injected engines, the manifold absolute pressure (MAP) sensor is one of the sensors an engine control module (ECM) uses to calculate fuel injection for optimal air-fuel ratio by continuously monitoring intake manifold pressure information. More commonly a mass airflow (MAF) sensor is used in place of a MAP sensor, however, turbocharged engines will typically use both a MAP and a MAF sensor.  The MAP sensor also provides a vital role in helping the ECM determine when the ignition should occur under varying engine load conditions. 

Whichever sensor your engine uses, the ECM will not be able to optimize fuel injection without accurate air mass information from a working sensor. And poor air-fuel ratio at the very least will cause performance issues and premature engine wear. A MAP sensor failure can be difficult to diagnose, but with the help from Delphi Technologies, we can explain what causes it, what to look out for, and how to replace it if it fails.

How does a MAP sensor work?

The MAP sensor is typically located on the intake manifold, either next to or on the throttle body itself. (On a forced-induction engine, the MAP sensor can be found on the intake tract before the turbo.) Inside the MAP sensor is a sealed chamber that either has a vacuum or a controlled pressure that is calibrated for the engine. Dividing the sensor vacuum and the vacuum from the intake manifold is a flexible silicon wafer (a.k.a. ‘chip’) with a current running through it.

The MAP sensor performs ‘double duty’ as a barometric pressure sensor as soon as the key is turned on.  With the key turned on (prior to the engine starting) there is no vacuum in the engine applied to the MAP sensor therefore it’s signal to the ECM becomes a baro reading helpful in determining air density.  When you start the engine, pressure in the intake manifold decreases creating a vacuum that is applied to the MAP sensor.  When you press on the gas accelerator pedal, the pressure in the intake manifold increases, resulting in less vacuum. The differences in pressure will flex the chip upward into the sealed chamber, causing a resistance change to the voltage, which in turn tells the ECU to inject more fuel into the engine. When the accelerator pedal is released, the pressure in the intake manifold decreases, flexing the clip back to its idle state. 

The ECU combines the manifold pressure readings from the MAP sensor with data coming from the IAT (intake air temperature), ECT (Engine Coolant Temperature) sensor, baro reading and engine speed (RPM) to calculate air density and accurately determine the engine’s air mass flow rate for optimal air-fuel ratio.

Why do MAP sensors fail?

Like most electric sensors, MAP sensors are sensitive to contamination. If the map sensor uses a hose, the hose can become clogged or leak and unable to read pressure changes. In some cases, extreme vibrations from driving can loosen its connections and cause external damage. Electrical connectors can also melt or crack from overheating due to close proximity to the engine. In either of these scenarios, the MAP sensor will need to be replaced.

What to look out for in a failing MAP sensor

A faulty MAP sensor will affect an engine’s air-fuel ratio. If the ratio is incorrect, ignition inside the engine will occur at an improper time in the combustion cycle. If severe pre-detonation continues over an extended time, the internal parts of the engine (such as pistons, rods, rod bearings) will become damaged and eventually lead to catastrophic failure. Look for these warning signs:

  • Rich air-fuel ratio:Look for rough idle, poor fuel economy, slow acceleration and a strong smell of gasoline (especially at idle)
  • Lean air-fuel ratio:Look for surging, stalling, lack of power, hesitation on acceleration, backfiring through the intake, and overheating
  • Detonation and misfire
  • Failed emissions test
  • Check engine light

A rebuilt engine is much more of a hassle than replacing a sensor, so if your engine is experiencing any of the symptoms above, consider troubleshooting your MAP sensor.

Common MAP sensor fault codes

Here is a list of codes that are associated with the MAP sensor to look for if your check engine light has turned on:

  • P0068:MAP/MAF – Throttle Position Correlation
  • P0069: Manifold Absolute Pressure – Barometric Pressure Correlation
  • P0105:MAP Circuit Malfunction
  • P0106:MAP/Barometric Pressure Circuit Range/Performance Problem
  • P0107:Manifold Absolute Pressure/Barometric Pressure Circuit Low Input
  • P0108:MAP Pressure Circuit High Input
  • P0109:MAP / Baro Pressure Circuit Intermittent
  • P1106:MAP/BARO Pressure Circuit Range/Performance Problem
  • P1107:Barometric Pressure Sensor Circuit Low Voltage

Note: Sometimes different sensors or other faulty parts can cause these codes to set. Even if your engine is experiencing the symptoms listed above and is firing one or more of the OBD-II codes listed, it is recommended to test the MAP sensor to confirm it is faulty.

How to troubleshoot a MAP sensor

Before any tests, inspect the physical appearance of the MAP sensor. Begin by checking the connector and wiring for any damage, such as melted or cracked wires, and confirm there are no loose connections. Disconnect the sensor and inspect the pins; they should be straight and clean with no signs of corrosion or bending. Next, inspect the hose (if applicable) connecting the sensor to the intake manifold for any signs of damage and that it has a tight connection to the sensor. Lastly, take a look inside the hose to make sure it is free of contamination.

If everything passes physical inspection, you can test the MAP sensor using a digital multimeter set to 20V and a vacuum pump.

  • With the battery on and engine off, connect the multimeter ground to the negative battery terminal and run a quick plausibility by checking the voltage of the battery. It should be around 12.6 volts.
  • Consult the manufacturer’s service manual to identify the signal, ground, and 5-volt reference and back-probe the wires.
  • Turn the ignition switch on without starting the engine. The multimeter should (typically) display a voltage between 4.5 to 5 volts for the 5-volt reference, a steady 0 volts for the ground wire, and between 0.5 and 1.5 volts for the signal wire on non turbo applications and between 2.0 and 3.0 for turbo applications. Consult OEM factory service information for the exact specs on your vehicle. 
  • Start the engine with the signal wire back-probed. The multimeter should display a voltage between .5 to 1.5 volts at sea level on non turbo charged vehicles and 2.0 to 2.5 volts on turbocharged models.
  • Turn the engine off but keep the ignition on.
  • Under the hood, disconnect the MAP sensor from the intake only.
  • Connect a hand vacuum pump and note the current voltage from the signal wire.
  • Increase the vacuum on the sensor using the vacuum pump.
  • The voltage should steadily drop as the vacuum increases.

If your voltage differs greatly on either test or the voltage change is erratic, the MAP sensor is faulty and will need to be replaced.

How to replace a faulty MAP sensor

Replacing a bad MAP sensor varies by vehicle, so please consult the manufacturer’s service manual for instructions for any specific instructions. Once the faulty sensor has been removed, it’s a straight forward installation for the new part. 

  • Locate the MAP sensor on the intake manifold, either next to or on the throttle body itself, or on the intake manifold. 
  • Remove any screws or bolts holding the sensor in place.
  • Disconnect the electrical connector. Note: Do not force removal as the connector may contain a locking tab that may need to be removed prior to unlatching the connector from the sensor.
  • If applicable, detach the vacuum hose from the sensor. Note: It is recommended to replace the vacuum hose with a new hose when replacing the sensor.
  • Compare the new and old sensors.
  • If applicable, reconnect the vacuum hose.
  • Reconnect the sensor electrical connector. 
  • Reinstall any screws or bolts that hold the sensor in place.
  • Double-check all connections to make sure everything is secured.

Note: Depending on the vehicle and if a trouble code was set, a diagnostic tool may be required to reset the check engine light.