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Jeremy, Certified Truck/Bus Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 3304
Experience:  ASE Med/HD Truck Technician, NATEF Diesel Engines and Electrical/Electronics Technician, EPA 608/609 HVAC Certified, Steering/Suspension and ABS/Brakes Technician
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We have an ISX Cummins. We are getting an active code

Customer Question

We have an ISX Cummins. We are getting an active code 689-Engine Crankshaft Speed/Position-Data Erratic, Intermittent, or Incorrect Code. What usually causes this?
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Jeremy replied 1 year ago.

My name is ***** ***** I will assist you.

A bad engine speed sensor followed by a short in the pigtail going to the sensor. These are the 2 most causes for this issue. After that it is the harness itself, wobble in the crankshaft, and then the ECM. ECM is super rare, as in almost never causes this issue.

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Customer: replied 1 year ago.
We are going to change the sensor know. Hopefully that fixes it. There wasn't any apparent splits in the harness.
Expert:  Jeremy replied 1 year ago.

Let me know of the outcome.

Usually when the harness tests good, the sensor is bad.

Expert:  Jeremy replied 1 year ago.

I see you viewed this and this is still showing as a open question due to no positive (3 stars or more) rating.

Did you still need assistance with this?

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