pcmhacking.net

Hi Everyone,

I know speedo correctors have been covered in many topics. I did a lot of reading here and ended up going for the 'Yellow Box' speedo corrector.

My car is a VS Calais.
I want to correct the speed going to the ECU. I have installed the corrector into the Blue/White wire going to the ECU. It works, but sometimes it is slow to react on take off. It has set off the VSS error code twice now.

Was I meant to install it at the Blue/White wire, or the Tan wire?

sounds like it's making the ecu unhappy with it's pulses or width. So probably easier to stick it between cluster and ecu just to get your speedo correct.

As far as I know, with an auto it's best to leave the speed to the ECU as is as the settings scale with diff changes without needing to do anything. As far as the ECU is concerned , it can't see the diff change and everything remains the same. The dash however is a different story.


In my case I had to use a correctors before both as the VN-VP the signal goes to the dash, then to the ECU as the dash does a divide by 5 function. My car is manual so it's less critical but I made sure the PPK was matching what the road speed is and it was without needing changing anything once the dash was calibrated.

Another thing is many corrector are pretty crappy and I use a VDO universal converter and it has option for 12v square in and out and other combos and it works flawlessly. Only thing is they are $$$, over 400 when I got mine in 2017.

I tried both on my car using the yellr with best results and cannot modify the signal to the ecu only the dash as it played havoc on cruise system as wasn't smooth. Then just need to adjust ecu to suit dash once it's all been dialed in and tweak shift points to suit