Join Date: Aug 2017
Location: Atlanta, GA
Drives: Sorento SX FWD 2015
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 25 Post(s)
You did not identify your model or engine so so the RPM to speed numbers will vary. Engine speed is delivered as data to the instrument cluster by the ECM via the CAN (Controller Area Network). A MCU (Micro Controller Unit) internal to the cluster converts the data to indicators. The ECM also sends Check Engine, Coolant Temp, Cruise and Cruise Set data (indicators) to the MCU/cluster on the same CAN lines. If these other indications work and the tac works up to 70 mph then the CAN buss between the ECU and MCU/cluster is most likely functioning. My V6 runs 2000 RPM at 70. My guess is a I4 would be a bit higher. I'm suspecting a bad cable connection to cluster (reseating) or MCU/Cluster failure or a ECM software problem.
Q1- If you put the car in neutral can you run the TAC up to 3000-3500 RPM ? That says MCU/Cluster is capable of handling the CAN RPM data over 70 MPH.
Q2- When on the road does the TAC go to 0 RPM or does it go blank at 70 MPH ? Thinking Maybe ECM software if display goes blank.
Are you still under warranty ?? New clusters vary $500-900 USD. You would really need verification/isolation prior to shotgunning parts. A dealer has tools and free parts access and can swap till they find the problem. Could be cheaper in the long run.
I'm Bob, 2015 Sorento SX , 2007 GMC Envoy (tuned) , 1994 Camaro Z28 (modified/custom tuned)
Last edited by bobdec; 06-02-2019 at 11:10 AM.