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I have a 2007 peterbilt vin#751984 The low coolant light…

Customer Question
Hello I have a 2007 peterbilt...
Hello
I have a 2007 peterbilt vin#751984
The low coolant light won't turn off.
I replaced sensor.
Submitted: 2 years ago.Category: Medium and Heavy Trucks
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Answered in 7 minutes by:
3/7/2016
Technician: Daniel Wilson,
 replied 2 years ago
Daniel Wilson
Category: Medium and Heavy Trucks
Satisfied Customers: 6,889
Experience: Owner at DJ Wilson
Verified

Hi my name is***** will be glad to help. What is the chassis model and your engine make and model? Check the harness between the sensor and ECM for damaged wiring and connector pins. I can help with some schematics if necessary once I have the engine and chassis information. Let me know

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Technician: Daniel Wilson,
 replied 2 years ago

If the coolant level is full and the sensor is new, the problem is most likely in the wiring between the sensor and ECM.

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Customer reply replied 2 years ago
389 peterbilt with a isx cummins
Customer reply replied 2 years ago
How much voltage should be going to the sensor?
Technician: Daniel Wilson,
 replied 2 years ago

Sensor voltage for all sensors will be a 5 volt signal from the ECM and then the ECM reads return voltage

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Customer reply replied 2 years ago
Ok
It has 5 volts on 1 of the wires.
Technician: Daniel Wilson,
 replied 2 years ago

click on this link for your diagram and ECM pin identification

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Technician: Daniel Wilson,
 replied 2 years ago

Pin 32 is the return on the OEM connector

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Customer reply replied 2 years ago
Is that the black connector?
Technician: Daniel Wilson,
 replied 2 years ago

Furthest to the Right facing the ECM ports

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Customer reply replied 2 years ago
do I test the pin on the ecm or the connector?
Customer reply replied 2 years ago
I tested pin 32 on the connector and there's no contact.
Technician: Daniel Wilson,
 replied 2 years ago

Thanks for the update, No continuity? so you have an open circuit or wire between the sensor and the ECM? If so make a test wire and run a test wire to see if the code goes away.

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Customer reply replied 2 years ago
Ok
Where would I run a test wire to?
Where would I tie it in to.?
Does the return wire go direct to the ecm or does it have a fuse in between?
Technician: Daniel Wilson,
 replied 2 years ago

Read the schematic I posted. it give the pins for the return of the sensor to the pin 32... see if the fault goes away.

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Technician: Daniel Wilson,
 replied 2 years ago

It shows another connector in the circuit as well going through pins A and B on that connector too.

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Technician: Daniel Wilson,
 replied 2 years ago

Shows Return is terminal A from the sensor black and white according to the schematic. Go from A from the sensor to 32 on the ECM

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Customer reply replied 2 years ago
I did that and there's no response.
Technician: Daniel Wilson,
 replied 2 years ago

Sounds like a problem with the ECM . Try having the software updated and reflashed to see if your problem resolves. Let me know.

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