Hey guys,
Have been reading everything in the community about these sensors and looks like I’m not the only one who has had issues.
Have followed the topic and tried everything to get this sensor to work correctly but to no avail. Pressure sensor never reads correctly and neither does temp. Have wired in an external 330 ohm pullup for the temp side but still no good with the calibrations even with the ecu using 1m pull down setting. Currently using AIN 5 for pressure and 6 for temp.
My question is, does the ground wire connect the vehicle ground or sensor ground to the ecu? Mine is currently wired up to sensor ground as this is what I assumed it should be.
Anymore info relating to this would be much appreciated.
Check your Pinout on the sensor. I know there are Konnecktors with diffrent Pin Numbers.
Sensorground is ok.
Hey mate,
Have wired up as per attached. What are the chances that the sensor is bought is no good?
Note that the temp side of this sensor cannot share the same 5v supply as the pressure side does.
NTC Thermistors must stand alone, however they can share the signal ground.
This is why the CLT and IAT have their own dedicated signal pins.
The 5v supply to a NTC is the signal wire.
Hope this helps.
This sensor is a 4 wire bosch combo. Both the temp and pressure share the 5v.
Both share the 5v.
This is a common misconception.
NTC thermistors can not share a power source.
They can only share a ground.
This is why you can not get the data to behave normally.
You need to supply the temperature circuit with its own 5v supply.
On a NTC circuit the ECU reads the voltage between two resistors in series.
The NTC Thermistor is one of these resistors. The ECU internal resistor is the other one.
However, this is only true if the ECU signal pin is supplying the power.
If it is not supplying the power you need to create externally and splice the analogue signal wire in between the two resistors on a 5v supply.
So how do you explain my above sensor then? Sensor clearly states what each pin is.
Yes. Sorry, I am describing a Pulldown design.
This sensor obviously divides the 5v supply internally (inside the sensor) and a 4k7 Pullup used inside the EMU black to provide the second resistor in series. The EMU Black is looking at the voltage before the internal Pullup resistor.
So the pressure side i have set the emu black to 1M pull down on both ain’s and tried adding the external 330 ohm pullup for the temp but it does not read correctly. The pressure side also does not work correctly.
Ok, sorry, I have been confusing pullup and pulldown and suggesting external resistor unnecessarily.
The sensor is doing a lot of the wiring work for you.
You just need to bring the temperature signal into the ECU with a 4k7 internal Pullup.
The Pressure signal does not need a pullup resistor.
Have done this with the internal 4k7. Sensor still does not read correctly.
Ok so you have
5v to sensor pin 3
Sensor ground (B29, B38, or B39 to sensor pin 4
AIN6 to sensor pin 5 with 4k7pullup
AIN5 to sensor pin 2
Correct?
That is correct. If it helps, when I change the resistance settings in the wizard the sensors react and also change. Nothing i have tried so far has worked though.
Check you have a good ground to the ecu.
You could do this by putting an incandescent globe (not an LED) test light from battery positive (+) to sensor harness pin 4. This will not hurt the ecu. Obviously you want a nice bright light.
You should also test the 5v supply with a multimeter.
Is the sensor in the block or on a remote oil line? Say, between the block and a cooler or even it’s own exclusive oil line?
If on the block, has it been in position on a running engine for a while before being wired up? Has it ever been dropped on a hard floor?
Pressure sensors do not like vibration and often fail prematurely when mounted on the block especially if balance shafts have been removed or solid lightweight crank pulleys have been put in place of a harmonic balancer. Putting oil pressure sensors in the old oil pressure switch location is a common practice that can cause early death of a sensor in some applications.
Not sure what else to suggest other than upload your project file here for us to have a look through to see if you’re missing something else.
Thanks for your responses mate. Much appreciated. I have a feeling the sensor may have failed given the wiring is good and no matter what i have tried it does not seem to work correctly.
Sensor is in a sensor block on the firewall to avoid vibrations and all that.
