No Speedo or Odo Even After Rebuilt Cluster???

[SaabMaster]

I recently got a 2008 Saab 97x and was told the Speedometer didn't work and some of other gauges would act up. I bought it as is and got 1 Heck of a deal (the 5.3 was just Rebuilt and still under warranty and the same with the Transmission) The Speedo doesn't move and the Odo doesn't rack up miles and the Tach was off at idle (1000 RPMs ODB2 showed 650rpms) and Fuel gauge showed over 1/4 tank when low fuel light was on and had burned 19 of 22 Gals. That was until we installed a Rebuilt Gauge Cluster and the Tach and Fuel Gauge was Fixed with that. But, that didn't resolve the Speedometer or the Odometer issues. ALSO, the Oil Pressure Gauge Shows Normal and then will Max Out and throw a code. I was told it has a New Oil Pressure Sensor. The Guy that Rebuilt the Cluster Says its Probably be a Short in a Wire and Other Mechanics Agree. Anybody that has dealt with this and has a Solution would be Much Appreciated.
Thanks in Advance!

 

[Mooseman]

Who was it rebuilt by? If it's from GM or from Dorman or some "real"company, it may need to be programmed.

 

[SaabMaster]

I had it rebuilt and programmed by a company in Kentucky I found online and that's all they do and have been doing it for years. I Trust that they did a good job.
Everything works better now Except for the Speedo and Odometer.

 

[Mooseman]

If the odo and speedo don't move, then it might not be communicating with the PCM and BCM which sends a signal to the cluster to move them via the databus.

What about the tach? Does it work? If it does, then I'd call the cluster defective. Everything goes through the databus.

 

[SaabMaster]

The tach works fine Now and the Speedo will jump to about 5 mph when I turn the key on but stays there until turned off.

 

[Mooseman]

All gauge data comes.through the same wire so I'd say the speedo/odo circuit in the cluster is defective. If there was no data, none of the gauges or lights would work.

Is it your cluster he rebuilt or is it another? You could just pick one up in a yard from any GMT360 2006 up and it would work, just the mileage would be off and colours would be different.

 

[SaabMaster]

The Speedo and Odo on the rebuilt Cluster is acting just like the Original Cluster.

 

[budwich]

Have you checked those "characteristics" with a obd interface looking at pcm data to see if there might be an issue there?

Quick read appears to indicate that the two items that don't work are calculated in the cluster based on "timed signals" from the PCM and ARE NOT sent as a "data stream" per se.
It would appear that your cluster is not getting that signal(s).

Do you have an "air suspension" system in the truck?

 

[Mooseman]

As per the schematics, the speedo signal is sent via the databus from the PCM/TCM. If there was an issue with the speed signal from the tranny to the PCM/TCM, it would throw some codes and light the CEL at the very least. It's a valid point to check that there are no issues there.

The fact that the speedo goes to 5mph and stays there tells me something is wrong in the cluster. If there was no signal, it would stay at 0 and the tach would still work.

 

[budwich]

I don't think you are reading the schematic that you posted correctly. The cluster is taking a "speed signal" in from the PCM and not from the data bus.

Further: NOTE there is a splice involved... hence the previous question about the truck options.

Potentially, the reason for the "speed difference" is that the signal has an issue in the wiring such that the "pulses" aren't very good...maybe.

 

[SaabMaster]

Have you checked those "characteristics" with a obd interface looking at pcm data to see if there might be an issue there?

Quick read appears to indicate that the two items that don't work are calculated in the cluster based on "timed signals" from the PCM and ARE NOT sent as a "data stream" per se.
It would appear that your cluster is not getting that signal(s).

Do you have an "air suspension" system in the truck?

Running "Live Data" on and ODB2 it shows the Speed and RPM Properly and Yes I have AirBags in the Rear and I have the Truck in at an Automotive Electrical Shop and he said the Leaking AirBags are 1/2 of the Battery Drain and he's trying it figure out the rest.

 

[Mooseman]

The airbag system shouldn't be activating while the vehicle is off. In fact, when you have leaking airbags, you usually find it in the morning with its rear end to the ground. Best way to fix it is to convert it to springs.

So back on topic. So with everything is working except the speedo so I would declare it suspect unless there is a wiring issue. A simple continuity test from the PCM to the cluster plug would confirm it.

 

[budwich]

so your PCM is getting the speed from the appropriate sensor. All you need to do now is check that one wire is going to the cluster and has some form of resistance on it (ie. it is neither a short nor open / high resistance). My guess would still be the splice is bad / has gone bad.

on the air bags... you are saying that they are an electrical drain... but are you saying that the compressor is running at "all times"?

Actually further thinking about this, the splice is probably not bad... :-( its more likely that the rear air bag controller is bad which is putting a load on the speed signal such that the cluster can't receive it well. Have you tried disconnecting the air bag controller to see if it results in any change in the cluster operation?

lastly: was work done on the ignition switch?

 

[SaabMaster]

so your PCM is getting the speed from the appropriate sensor. All you need to do now is check that one wire is going to the cluster and has some form of resistance on it (ie. it is neither a short nor open / high resistance). My guess would still be the splice is bad / has gone bad.

on the air bags... you are saying that they are an electrical drain... but are you saying that the compressor is running at "all times"?

Actually further thinking about this, the splice is probably not bad... :-( its more likely that the rear air bag controller is bad which is putting a load on the speed signal such that the cluster can't receive it well. Have you tried disconnecting the air bag controller to see if it results in any change in the cluster operation?

lastly: was work done on the ignition switch?

The ignition switch was changed out as it was an auction car. Haven't disconnected anything yet. The air bags are weather checked and they leak from being deflated for a long time.

The airbag system shouldn't be activating while the vehicle is off. In fact, when you have leaking airbags, you usually find it in the morning with its rear end to the ground. Best way to fix it is to convert it to springs.

So back on topic. So with everything is working except the speedo so I would declare it suspect unless there is a wiring issue. A simple continuity test from the PCM to the cluster plug would confirm it.

I have it at an Automotive Electrical Shop and they are trying to figure out what's wrong.

 

[SaabMaster]

If the odo and speedo don't move, then it might not be communicating with the PCM and BCM which sends a signal to the cluster to move them via the databus.

What about the tach? Does it work? If it does, then I'd call the cluster defective. Everything goes through the databus.

The shop I have it at told me today that he thinks it may be the BCM. And he got the battery drain fixed someone had ran a hot wire jumper from a to the Ignition. He disconnected it and says he doesn't know why they would have done that? Plus, the Alternator is cranking out like 16.8 volts instead of 14 which is wierd?

 

[Mooseman]

I know what I said before but just going by the schematics, the BCM isn't in there at all.

Running "Live Data" on and ODB2 it shows the Speed and RPM Properly

This tells me the signal is there and that the cluster is defective. I'd swap it out with another one from a junker as a test and see if it works. Another thing to check is continuity from the PCM to the cluster on that wire that sends the signal.

 

[budwich]

now you are talking...

 

[SaabMaster]

I know what I said before but just going by the schematics, the BCM isn't in there at all.



This tells me the signal is there and that the cluster is defective. I'd swap it out with another one from a junker as a test and see if it works. Another thing to check is continuity from the PCM to the cluster on that wire that sends the signal.

The guy said it could be the PCM or BCM so maybe it's the PCM and I wonder since the Alternator Regulator is not working the High Voltage messed up the PCM.

 

[SaabMaster]

Got the issues with the 97x fixed finally.
Had it at an Automotive Electrical Shop and he fixed some wiring issues and the power drain but threw his hands up on the Speedo and ODO issue. So, he suggested a Transmission shop and they replaced and programmed the ECM and it's done. Tomorrow I get New Tires and TPMS Sensors installed then r&r the Rear AirBags and Oil Pressure Sensor and it's should be go to go.

 

[mrrsm]

If the Question is not too indiscreet… would you mind telling us in a Round, Ball Park Figure how much it cost you from start to finish on this repair? The reason I ask is that I’m wondering if having your own Tech 2 Scanner & Kit would have saved you any money if you’d have had the chance to do your own Dealership Quality Diagnosis and ability to Update the PCM and Module Software? Thanks in Advance for your reply.

Post #173 & #174 from this Link.

https://gmtnation.com/forums/threads/new-complete-kit-gymko-gm-tech-2-scan-tool.17878/page-5

 

[Mooseman]

The PCM was at fault? Very strange. Definitely one for the books.

Was a reprogram attempted before replacing the PCM?

 

[SaabMaster]

They said the ECM was Fried and needed replaced cause it had some bad circuits and couldn't communicate with the cluster. It is now programmed with the latest software and all the updates.
The ECM was almost $400 and after diagnosis and programming and install it was $925.