Chevrolet Suburban 3500 Questions

[Geotrash]

Are you sure it even has one? If your cluster came from a 1500, it could be a no-comm error because it's not seeing a module it expects to see. Check for codes in the cluster itself to see if there is a no-comm code.

There is. It's a lost communication code but it's for the HUD display, which my cluster has enabled but I do not have the module installed for. And there is also a security code error.

You might be on to something though because the 1500's have electrically assisted power steering, but the 3500 has hydraulically assisted power steering. Still, I can't figure out why the instrument cluster would care about the steering control module. It's been programmed to the VIN as well, but that may not matter.

Unrelated, I believe, but I also had a code that has since reset itself for the fuel pump in the rear tank:

 

[Geotrash]

Here's a little more detail on the errors. One other thing is that because the cluster isn't the one that came with the truck, I can't program/update it with the SPS software because the updates SPS wants to apply are keyed off the VIN. Starting to wonder if the Denali cluster upgrade was worth it. Glad I kept the original, just in case.

Update: I wrote to White Automotive today and they confirmed that the instrument cluster messages are both normal, so I'll quit worrying about them. The Service Power Steering message is continuing to vex me, however.

 

[Bigburb3500]

Here's a little more detail on the errors. One other thing is that because the cluster isn't the one that came with the truck, I can't program/update it with the SPS software because the updates SPS wants to apply are keyed off the VIN. Starting to wonder if the Denali cluster upgrade was worth it. Glad I kept the original, just in case.

Update: I wrote to White Automotive today and they confirmed that the instrument cluster messages are both normal, so I'll quit worrying about them. The Service Power Steering message is continuing to vex me, however.

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It’s more annoying than anything because what happens when you do have a problem?

 

[TripleFJeff]

Assuming that the issue is a no-comm (which jives with the report above), the message is being triggered one of two ways. The first is that the cluster itself is monitoring the presence of the steering module, and reporting the fault when it doesn't see it. The other is that some other module is monitoring it, and when it sees a fault it is sending a message to the cluster to show the fault in the display. The second seems more likely, since the cluster probably doesn't need anything from the steering module so it wouldn't be monitoring it for no-comm.

While your cluster may have been programmed to your VIN for anti-theft, since it's not a valid part for your truck I wouldn't expect that it is configured properly for what parts yours has.

 

[Geotrash]

It’s more annoying than anything because what happens when you do have a problem?

Another good reason to keep the original cluster. If I ever have a problem that requires cluster programming, I can just pop in the original. In the meantime, I really like the functionality in the Denali cluster. The transmission fluid temperature gauge in tow/haul mode is wonderful, for example.

 

[Geotrash]

Assuming that the issue is a no-comm (which jives with the report above), the message is being triggered one of two ways. The first is that the cluster itself is monitoring the presence of the steering module, and reporting the fault when it doesn't see it. The other is that some other module is monitoring it, and when it sees a fault it is sending a message to the cluster to show the fault in the display. The second seems more likely, since the cluster probably doesn't need anything from the steering module so it wouldn't be monitoring it for no-comm.

While your cluster may have been programmed to your VIN for anti-theft, since it's not a valid part for your truck I wouldn't expect that it is configured properly for what parts yours has.

This is what I’m thinking as well. However, I expected the GM software to be able to get the modules right. So, I’m thinking I still have a communication problem on the CANbus with the steering control module.

 

[TripleFJeff]

This is what I’m thinking as well. However, I expected the GM software to be able to get the modules right. So, I’m thinking I still have a communication problem on the CANbus with the steering control module.

The GM software only allows you to program a module for a vehicle that it available on, and you need a VIN to do it. For example, my 2500 originally came with tow mirrors and a prior owner had swapped on non-tow, power fold mirrors mirrors but didn't change the door switch module to one with the power fold button. I swapped the door switch module to one with power fold, but then my driver's side heated seat quit working because the switch came from a truck without heated seats. You can't just change that parameter. I had to go on autotrader and find a truck that had heated seats and power fold mirrors (and matched everything else), and use that VIN to program my switch module. So if that cluster never came on a truck without a steering module, it's impossible to fix.

That said, I'm still 99% confident that your truck does not have a steering module. Have you actually put hands on it? Are there any electrical connectors that go to the steering gear or pump?

 

[Geotrash]

The GM software only allows you to program a module for a vehicle that it available on, and you need a VIN to do it.

Thank you for your continued thoughts. I had this thought as well, yet entering the VIN in the GM software and website still returns that it has a power steering control module. And the cluster was programmed to the VIN as well, by White Automotive. The fly in the proverbial ointment though is that the cluster came from a different year Denali. But given that none of the 3500’s were Denali’s, I don’t know that it would matter. None of them were likely configured with the 3500-specific features.

For example, my 2500 originally came with tow mirrors and a prior owner had swapped on non-tow, power fold mirrors mirrors but didn't change the door switch module to one with the power fold button. I swapped the door switch module to one with power fold, but then my driver's side heated seat quit working because the switch came from a truck without heated seats. You can't just change that parameter. I had to go on autotrader and find a truck that had heated seats and power fold mirrors (and matched everything else), and use that VIN to program my switch module. So if that cluster never came on a truck without a steering module, it's impossible to fix.

I had this thought also. I have programmed many modules to the VIN of my Yukon XL’s using a Tech 2. But like you, I can’t figure out what the cluster would have to do with the power steering control module except to be the receiver of any fault indications. All the same, that the cluster is creating the issue is the most plausible theory I have so far.

That said, I'm still 99% confident that your truck does not have a steering module. Have you actually put hands on it? Are there any electrical connectors that go to the steering gear or pump?

No, but the GM software indicates at least 6 different BCM “modules”, so I’m not sure it would be a physical module. It may occupy a logical space on the BCM’s mainboard or reside in the BCM’s housing. I also looked for electrical connectors and while there are several on the steering column, there appear to be none on the steering pump or steering gearbox. It has the same reciprocating ball setup as the GMT900 2500 platform.

Also, I would think that the Stabilitrak system needs a source of steering data, so unless that’s coming from a different module, I would think it still needs a steering control module of sorts. But again, I have no data on it. Alldata thinks it has a rack and pinion setup, so I don’t trust the schematics. Though they do denote which drawings are applicable to the L96-equipped trucks, of which the 3500 is the only one so equipped.

I’ll ask the guys over at duramax specialties on their Facebook page. They’re really good about helping folks out, even those who don’t have one of their rigs.

 

[Geotrash]

Update: the owner of Duramax Specialties is a great guy and was kind enough to confirm that the 3500 HD Suburbans DO NOT in fact have a Power Steering Control Module. He suggested I get with the White Automotive to have them deal with the error. I'll reach out to them today and see what they say.