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Info guides and mods

Sensors (Suprex)

What they are,where they are and what they do.

Modification Details




MAP Sensor

What Does It Stand For?
Mass/Manifold Absolute Pressure
What Does It Do?
It monitors the boost and vacuum of the air inlet manifold.
What Happens If It Is Faulty?
The engine may not boost properly or may go into safe mode.
Where Is It?
In the engine bay, over to the right.



How To Remove It
Use a Torx30 bit, remove the bolt. The MAP sensor will now pull out.





IAT Sensor

What Does It Stand For?
Inlet Air Temperature
What Does It Do?
It monitors the temperature in the air inlet manifold.
What Happens If It Is Faulty?
May run badly, could run very rich or lean, engine could stall.
Where Is It?
In the engine bay, over to the right. Left of the MAP sensor (petrol).
Pushed into the bottom of the intercooler (diesel).



How To Remove It
Squeeze the plastic tabs on each side and pull, the sensor should slide out.





Coolant Temperature Sensor

What Does It Do?
It monitors the temperature of the coolant in the engine.
What Happens If It Is Faulty?
Engine can overheat or have problems reaching full temperature.
Where Is It?
In the engine bay, near the back behind the inlet manifold.



How To Remove It
Lever the metal clip out and pull the sensor straight up.



Lambda/Oxygen Sensors

What Does It Do?
It monitors the fuel and air mixture in the exhaust system.
What Happens If It Is Faulty?
The fuel/air mixture will be wrong and the engine check light will show.
Where Is It?
One in the turbo and one in the exhaust. Older models may just have one sensor.



How To Remove It
Unplug it and use a 22mm spanner to twist it out.



Gear Position Sensor

What Does It Do?
It's used to set up the gear positions when they are taught on an MB Star diagnostics machine.
What Happens If It Is Faulty?
Probably nothing unless you are teaching the gear positions on MB Star.
Where Is It?
On the bottom of the engine, on the left hand side towards the middle,
near the back, on the side of the gearbox, near the air scoop.



How To Remove It
Remove the Torx bolts and the sensor will come free.



Oil Pressure Sensor

What Does It Do?
It monitors the pressure of the oil in the engine.
What Happens If It Is Faulty?
Oil pressure light will illuminate on the speedo.
Where Is It?
On the bottom of the engine, above the oil filter.



How To Remove It
Disconnect the wire and undo the retaining nut with a 24mm spanner.



Knock Sensor

What Does It Do?
It monitors the engine for pinking.
What Happens If It Is Faulty?
The ECU won't alter the fueling to stop pinking, performance can be affected.
Where Is It?
On the back of the engine near the alternator.



How To Remove It
Remove the torx bolt and the sensor will come free.



Wheel Rotation Sensors (ABS/ESP)

What Does It Do?
They monitor the reluctor rings behind each wheel to assess if a wheel is skidding.
What Happens If It Is Faulty?
ESP or Trust warning light will show, you may lose drive or safety systems can shut off.
Where Are They?
Rear wheel sensors - Behind the rear drums.



Front wheel sensors - Behind the brake discs and the dust covers.



How To Remove It
Remove the E socket bolt from the back of the sensor and remove from hole.



Yaw/Lateral Movement/G-Force Sensor

What Does It Do?
Measures the lateral forces of the car.
What Happens If It Is Faulty?
ESP or Trust warning light will show, you may lose drive or safety systems can shut off.
Where Are They?
600cc - Underneath the undertray on the nearside.



700cc - Underneath the seat, underneath the carpet.





Steering Angle Sensor

What Does It Do?
Measures the angle of the steering wheel.
What Happens If It Is Faulty?
ESP/Trust light, ABS light and handbrake light will show. Safety systems turn off.
Where Is It?
On the back of the steering wheel, only on 700cc and newer diesels.





Crankshaft Rotation Sensor (TDC)

What Does It Do?
Counts the rotation of the engine.
What Happens If It Is Faulty?
Can cause the engine to stall when hot or not start at all. Click here.
Where Is It?
On the top of the bell housing directly below the throttle body.





Gearbox Rotation Sensor

What Does It Do?
Counts the rotation of the gearbox.
What Happens If It Is Faulty?
The car usually won't change up when driven in automatic
Where Is It?
On the back of the gearbox above the clutch actuator motor hidden by the intercooler scoop.
Error Codes
P0715, P0716, P0717, P0718.





Ambient Temperature Sensor

What Does It Do?
Relays the external temperature to the speedo and the air conditioning.
What Happens If It Is Faulty?
Air conditioning may not come on, speedo will read incorrect temperatures like -16 degrees.
Where Is It?
In the front lower nearside air dam in the front bumper.




Transmission Oil Temperature Sensor

No Photo

What Does It Do?

Monitors the temperature of the transmission fluid
What Happens If It Is Faulty?
Engine check light will probably illuminate
Where Is It?
On the side of the very early 600cc gearbox bellhousing beside the clutch actuator motor.

Error Codes
P0710, P0711, P0712, P0713, P0714.


Click if Info Helpful

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