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I do not have a supply voltage to MAF sensor

Tiny
GEORGE TODD
  • MEMBER
  • 2001 LAND ROVER DISCOVERY 2
  • 2.5L
  • 5 CYL
  • TURBO
  • 4WD
  • MANUAL
  • 78 MILES
Looking for electrical drawing or pin out MAF to ECU so I can test continuity before stripping section of wiring loom.

Thanks
Friday, January 17th, 2020 AT 2:24 AM

14 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

The brown/pink wire is the one that supplies 12 volts to the sensor. It is controlled by a fuse. I attached the diagram for you of the wiring.

The other 4 go to the ECM for the controls.

https://www.2carpros.com/articles/how-to-check-wiring

Roy
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Friday, January 17th, 2020 AT 2:41 AM
Tiny
GEORGE TODD
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  • 6 POSTS
So I should have continuity between fuse 2 and MAF sensor. Note MAF sensor only has 3 wires.

TIA
George
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+1
Saturday, January 18th, 2020 AT 10:12 AM
Tiny
ASEMASTER6371
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Correct. The power comes from the fuse as in the diagram.

Can I have the complete VIN if you have a 3 wire sensor?

Roy
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Sunday, January 19th, 2020 AT 5:38 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,904 POSTS
I have never seen a MAF with 3 wires? Can you double check the engine size 2.5?
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Monday, January 20th, 2020 AT 10:20 AM
Tiny
GEORGE TODD
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  • 6 POSTS
Seems to be standard on the discovery 2.
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Monday, January 20th, 2020 AT 11:47 AM
Tiny
ASEMASTER6371
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Could you please post the VIN number for me?

Roy
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Monday, January 20th, 2020 AT 11:52 AM
Tiny
GEORGE TODD
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  • 6 POSTS
See photo.
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Monday, January 20th, 2020 AT 12:21 PM
Tiny
ASEMASTER6371
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Thank you.

This is a turbo diesel. I will need some time to track down the information.

Roy
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Monday, January 20th, 2020 AT 1:12 PM
Tiny
GEORGE TODD
  • MEMBER
  • 6 POSTS
Yeh Td5.
What problems would a faulty MAF sensor give?
The understanding I have pin.
1 ground.
3 live feed.
2 signal return. (Vary between 1 and 5 volt)
Now have live feed, bur nothing on pin2 and no air flow on obd reader.
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Monday, January 20th, 2020 AT 1:38 PM
Tiny
ASEMASTER6371
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Okay, there should be a 5-volt reference voltage supplied by the ECM. There will be a return or ground going back to the ECM as well. The third wire is the signal wire. That will have 5 volts as well and will vary in voltage from 0 to 5 volts depending on engine load. As you accelerate the voltage should change on the signal wire. If it does not, then you either have a bad sensor or a broken wire.

Roy
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Monday, January 20th, 2020 AT 3:04 PM
Tiny
GEORGE TODD
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  • 6 POSTS
Thanks Roy. Got 12v (supply) but nothing on signal wire. I have pinned the back of sensor so even with a damaged signal wire I should still get something?
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Tuesday, January 21st, 2020 AT 1:07 AM
Tiny
ASEMASTER6371
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That is correct. It comes from the ECM to the sensor.

Roy
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Tuesday, January 21st, 2020 AT 5:15 AM
Tiny
GEORGE TODD
  • MEMBER
  • 6 POSTS
Is signal not from sensor to ECU.
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Tuesday, January 21st, 2020 AT 6:33 AM
Tiny
ASEMASTER6371
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No, the ECM sends a signal voltage, then the sensor will drop or rise that voltage depending on the amount of air going through the sensor.

Roy
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Tuesday, January 21st, 2020 AT 6:40 AM

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