1999 E-350 speedometer malfunction

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Feb 28, 2024 | 02:27 PM

Bigw

Thread Starter

4wd Low

Joined: Jan 2021

Posts: 11

Likes: 2

1999 E-350 speedometer malfunction

My 1999 E-350 van suddenly began having erroneous speed readings. The speedo goes from zero to 40 MPH as soon as van begins to roll…..the it does not increase to true speed beyond 40 MPH. When van slows to zero the speedo gradually goes back down to zero MPH. No Check Engine light, trans shifts well, cruise seems to work fine, …..I just replaced the battery and before replacing battery did a jump start. Speedo worked fine for over 100 miles before malfunction. Please give me some ideas about how to troubleshoot. Thanks!

Feb 28, 2024 | 07:55 PM

DBGrif91

Cargo Master

Joined: Jul 2009

Posts: 2,541

Likes: 54

From: Des Moines

It’s not likely to matter, but what engine? There could be minor differences in the connecting circuits at the IPC connectors.

The speedometer is logic controlled within the IPC. The VSS is directly fed to the IPC and PCM/TCM.

If you’re not experiencing any shift or driveability issues, it’s likely the cluster is at fault. A scan tool or app that can check live data within the cluster would be the most useful/effective way to determine if it’s a cluster or signal problem.

Mar 6, 2024 | 01:54 PM

blageurt

Fleet Mechanic

Joined: May 2011

Posts: 1,414

Likes: 10

From: Thornhill , Ontario

I had similar Issues with my 99 Diesel and all I did was remove / replace all the relevant Fuses and Relays and it stopped ....If you have the manual it tells you what is what ...Otherwise you need the Electrical Service Manual ....some times it is just a bad contact or wire rub -out ...buy a can of Electric Contact Cleaner and some Dieelectric Grease and go to town ...Also Clean and Tighten your Battery Terminals too ....Good Luck ....