speedometer problem
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
I do not understand what you did, what he used, and where was it connected. More info is needed to use in our analysis. We know the VSS signal is getting to the DIC/cruise control, and active handling (ECBM) so we need to know more about what he did.With that said I am thinking it is the actual speedometer but until I can rule out the last few things I am not ready to recommend a root cause (this I would like to have Lionelhutz agree with before we start replacing parts). I plan to call an IPC repair shop this morning and find out if the initial sweep is internal or from the PCM. That info is critical for me.
Also, do the other gauges sweep normally at startup? I don't have my car here at home but as I remember at least the Tach and the speedo do. I think all the gauges do this.
Did you disconnect the battery for a few minutes and see if that did anything?
Once I get the above info we can assess where we are at and see if we need to inspect the PCM (I don't think you have not done that yet)
See you again soon (here). Sam
Also, do the other gauges sweep normally at startup? I don't have my car here at home but as I remember at least the Tach and the speedo do. I think all the gauges do this.
Did you disconnect the battery for a few minutes and see if that did anything?
Once I get the above info we can assess where we are at and see if we need to inspect the PCM (I don't think you have not done that yet)
See you again soon (here). Sam
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
I have talked with one repair service and they say the gauges sweep on IPC powerup (IPC gets voltage applied)and are not swept by the PCM. I plan to call another shop to get confirmation but they are in California and so I need to wait until they open in a couple of hours.
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
The hand-held test tells us nothing new. We already knew the PCM was receiving the speed data.
The speedo not sweeping would make me believe the cluster does have an issue but without checking the wiring and testing the PCM output I can't say that is the only issue.
The speedo not sweeping would make me believe the cluster does have an issue but without checking the wiring and testing the PCM output I can't say that is the only issue.
Le Mans Master
Joined: Sep 2003
Posts: 6,276
Likes: 227
From: Farmington CT
Cruise-In VII Veteran
your in Austin TX; home of 3500 Corvettes.
I'd swap out the cluster in 20 minutes and then go the T/S route.
The VSS(vehicle speed sensor/signal) is on the top of the diff, one bolt, 2 wires, is she plugged in??
I have clusters in stock ready to ship if needed.
HTH
Steve
I'd swap out the cluster in 20 minutes and then go the T/S route.
The VSS(vehicle speed sensor/signal) is on the top of the diff, one bolt, 2 wires, is she plugged in??
I have clusters in stock ready to ship if needed.
HTH
Steve
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
Phil, I talked with the other repair shop. They agreed IPC gauge sweeps are done internal to the IPC and are not dependent on the PCM. They said the motor is bad or there is an internal power issue to the motor. My assessment is you need the IPC repaired or replaced. Hopefully it will resolve the PCM code, I think it will. If it were me I would address the IPC first since it appears to be bad based on my opinion and that of 2 repair shops. I would like Lionelhutz to weigh in on this so he either agrees or we look at this further before you remove the IPC.
PS: If you do remove the IPC you might consider installing a HUD. That is if you want to have one. I love mine.
PS: If you do remove the IPC you might consider installing a HUD. That is if you want to have one. I love mine.
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
Yes, Steve the sensor is plugged in and working. We established that days ago.
The handheld plugged into the diagnostic port is reading the speed data from the PCM via the OBDII serial port. Knowing that is working really doesn't help because we already established the PCM is reading the speed when you tried the cruise control and the cruise worked and displayed the set speed on the DIC.
The speedo not sweeping says the cluster does have an issue. As I posted before, the speedo stepper motor being stuck or burned out doesn't really explain why the PCM thinks the dedicated VSS signal circuit has failed. Possibly, the motor burning out also burned out the circuitry for that dedicated VSS signal. The only way to know is to try another cluster.
The handheld plugged into the diagnostic port is reading the speed data from the PCM via the OBDII serial port. Knowing that is working really doesn't help because we already established the PCM is reading the speed when you tried the cruise control and the cruise worked and displayed the set speed on the DIC.
The speedo not sweeping says the cluster does have an issue. As I posted before, the speedo stepper motor being stuck or burned out doesn't really explain why the PCM thinks the dedicated VSS signal circuit has failed. Possibly, the motor burning out also burned out the circuitry for that dedicated VSS signal. The only way to know is to try another cluster.
Thread Starter
Instructor
Joined: Mar 2013
Posts: 137
Likes: 0
From: Austin TX
lionelhutz
So it looks like were leaning toward a bad speedo,knowing this would you buy a new one a used one or have the original fixed. If I buy used or new I would still have to send it of so that it can be programed with the correct mileage,the cost seems to be close either way I go.
Phil
So it looks like were leaning toward a bad speedo,knowing this would you buy a new one a used one or have the original fixed. If I buy used or new I would still have to send it of so that it can be programed with the correct mileage,the cost seems to be close either way I go.
Phil
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Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
I might just try to find one close mileage and stick it in, but that would be breaking the law. Yes, any used one would have to be programmed if you wanted it to be correct. I have no idea what the costs of the different options would be in your area so pick the option that seems best. You could use any possible warranty as the deciding factor.
There is a circuit board on the back that holds the mileage info and it is fairly easy to swap. However, I couldn't tell you if it could be part of the problem or not. You could try the used cluster first and if it works then swap the board and see if it still works.
There is a circuit board on the back that holds the mileage info and it is fairly easy to swap. However, I couldn't tell you if it could be part of the problem or not. You could try the used cluster first and if it works then swap the board and see if it still works.
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
If it were me, I would get it fixed since it should be cheaper and would keep the mileage. With that said, see if the local dealer can fix the mileage, that might affect how you think about options. Keep us posted on how things go and if that resolves all the speedo issues or not.