Question on VSS on 06 rear diff case in a 05
07-07-2011, 10:59 PM
#1
7th Gear
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Question on VSS on 06 rear diff case in a 05
I have a 2005 C6 here with a RPM Transmission Stage 2 rear differential upgraded to a 2006 case. The car has the stock 4L60 transmission. I bought the car like this.
My problem is that the cruise doesnt work. The speedo reads correctly but when monitoring the VSS signal in the ECM, it's not correct. When going 60mph according to the speedo, the VSS in the ECM only reads 18mph. If I speed the car up to around 80 mph, the VSS in the ECM reads 25mph and the cruise will then work...obviously since the ECM sees it has met its 25mph minimum.
I looked for the VSS on the rear differential and it's not there. I can't even find a harness from where the stock one was plugged in. I take it that the 06 case's must get vehicle speed from the transmission rather than the rear diff??
Here is what I don't understand... how can the speedo read correct but the VSS in the ECM doesn't? According the the wiring schematic, the vehicle speed is sent to the speedo from the ECM.
Don't know where to head with this one...I hoping someone has had a similar problem and can point me in the right direction.
Thanks!
My problem is that the cruise doesnt work. The speedo reads correctly but when monitoring the VSS signal in the ECM, it's not correct. When going 60mph according to the speedo, the VSS in the ECM only reads 18mph. If I speed the car up to around 80 mph, the VSS in the ECM reads 25mph and the cruise will then work...obviously since the ECM sees it has met its 25mph minimum.
I looked for the VSS on the rear differential and it's not there. I can't even find a harness from where the stock one was plugged in. I take it that the 06 case's must get vehicle speed from the transmission rather than the rear diff??
Here is what I don't understand... how can the speedo read correct but the VSS in the ECM doesn't? According the the wiring schematic, the vehicle speed is sent to the speedo from the ECM.
Don't know where to head with this one...I hoping someone has had a similar problem and can point me in the right direction.
Thanks!
07-08-2011, 08:32 AM
#2
Tech Contributor
Forum sponsor ragtopws6 can likely help you. He's dealt with the 06+ on an 05 and the attendant issues.
http://forums.corvetteforum.com/memb...ragtopws6.html
http://forums.corvetteforum.com/memb...ragtopws6.html
07-08-2011, 09:16 AM
#3
Melting Slicks
vss is in the very top of the diff case on ALL C6. you have a comunication issue, or a cruise unit that is malfunctioning. you need a tech 2 scan tool or one similar to properly diagnose your problem.
07-08-2011, 09:31 AM
#4
Tech Contributor
The 05 is finicky because of the "put in reverse to shut down" issue. If the car has an 06+ trans as well as the diff, the installer has to get creative with the wiring to make sure the car shuts down as the 06 tranny isn't milled and drilled for the second sensor.
Plus, I understand the 05 uses a reluctor wheel for the VSS but the 06+ uses the ring gear. I think that's the OP's issue, and there's a fix but I don't know it. I know you can change the pulses for the VSS with HP Tuners, it might be that easy.
Ragtopws6 does this conversion all the time and will know what to do.
Plus, I understand the 05 uses a reluctor wheel for the VSS but the 06+ uses the ring gear. I think that's the OP's issue, and there's a fix but I don't know it. I know you can change the pulses for the VSS with HP Tuners, it might be that easy.
Ragtopws6 does this conversion all the time and will know what to do.
07-08-2011, 10:02 AM
#5
Former Vendor
The car above is a 4L60e with our billet adapter plate. So it doesn't have the Reverse switch on the side of the transmission.
(FYI if we build an 06 up transmission and differential for an 05 we always use the correct case with both reverse sensors so the car retains all factory functions without modifications)
The speed sensor is on the top of the differential, but the speedometer is working correctly so there is not an issue with the speed sensor.
05 Cars have funky tuning for MPH calculations, the car has a tuning issue because of the gear change in the differential. You need to take the car back to the tuner for diagnostics.
(FYI if we build an 06 up transmission and differential for an 05 we always use the correct case with both reverse sensors so the car retains all factory functions without modifications)
The speed sensor is on the top of the differential, but the speedometer is working correctly so there is not an issue with the speed sensor.
05 Cars have funky tuning for MPH calculations, the car has a tuning issue because of the gear change in the differential. You need to take the car back to the tuner for diagnostics.
07-08-2011, 10:34 AM
#6
Race Director
The car above is a 4L60e with our billet adapter plate. So it doesn't have the Reverse switch on the side of the transmission.
(FYI if we build an 06 up transmission and differential for an 05 we always use the correct case with both reverse sensors so the car retains all factory functions without modifications)
The speed sensor is on the top of the differential, but the speedometer is working correctly so there is not an issue with the speed sensor.
05 Cars have funky tuning for MPH calculations, the car has a tuning issue because of the gear change in the differential. You need to take the car back to the tuner for diagnostics.
(FYI if we build an 06 up transmission and differential for an 05 we always use the correct case with both reverse sensors so the car retains all factory functions without modifications)
The speed sensor is on the top of the differential, but the speedometer is working correctly so there is not an issue with the speed sensor.
05 Cars have funky tuning for MPH calculations, the car has a tuning issue because of the gear change in the differential. You need to take the car back to the tuner for diagnostics.
my 05 a4 reads about 14 mph diferent on the dic cruise speed then the speedometer, after a gear change, but when im doing 60 mph and set the cruise its doing 60mph the dic is only reading 46 mph. so before i ever had a car that had a dic i looked at the speedometer, so i just look at the speedometer not the dic
