AIT sensor failed reads (4996mV)

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RS2000Jens
Posts: 2
Joined: Tue Apr 28, 2020 3:40 am
ECU Model: S80 Pro

AIT sensor failed reads (4996mV)

Post by RS2000Jens »

Hi Guys,

I'm relatively new to this game.
My problem is that the AIT sensor part of my TMAP sensor (Bosch 0261 230 053) is reported as failed.
The voltage reading is steady at 4995 mV
MAP reads ok ish... (90kPa with engine not runing)
I used the DTA default cal for it (Bosch 0230 260 037 105kPa sensor) as it is the closest I could find... and they are both 105kPa sensors...
The resistance of the sensor (pin 1 to pin 2) is about 3.8kOhm at 15°C.
However even with the sensor disconnected the S80 reads 4995mV for AIT
So I checked the cables for continuity between 5V supply (ECU pin 9) and pin 7 and there is none (sensor disconnected)
I had the ECU with Alex a week ago and he checked it and it is all OK
Am I missing something?
Rob Stevens
Posts: 1137
Joined: Thu Jul 28, 2011 4:10 am
ECU Model: S100 Pro
Distributor: None-Coil On Plug :)

Re: AIT sensor failed reads (4996mV)

Post by Rob Stevens »

I think the 5v you are seeing is the internal pull up 5v inside the ECU, suggesting either open circuit sensor or or wire to it. Clearly the earth is ok as the pressure sensor is ok. The temp bit of the sensor doesn't use the 5v.
Something wrong with your pressure calibration also, you should be reading more like 99 unless you live up a mountain
RS2000Jens
Posts: 2
Joined: Tue Apr 28, 2020 3:40 am
ECU Model: S80 Pro

Re: AIT sensor failed reads (4996mV)

Post by RS2000Jens »

Hi Rob,
Thanks for the fast reply.
Open circuit sounds like a possibility...
Checked everything again.
The sensor has a resistance of 4.7kOhm between pin 7 and 33 (OK for the plenum temperature) Measured at the connector without ECU
I agree the pressure cal is of.... need to borrow the vacuum pump from work next week ;-)
stevieturbo
Posts: 3271
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: AIT sensor failed reads (4996mV)

Post by stevieturbo »

simple test for an open circuit at the sensor.....short the two pins. If it stays open circuit there is a wiring issue...if it doesn't, there isn't lol
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