So I have been getting Traction Control and Active Handling error codes along with others and dealer gave me a data recorder to try to "capture" the event when it happens. Finally got a good capture today and he notices when looking at the run time on the computer that it goes from 33,34,35,36,37,38,39,40,27,44,45. He says that the PCM internal clock has reset itself from 40 down to 27 then back to 44. Is going to order a new PCM. Also notices the rpms are fluctuating alot so I am going to try to "capture" another event and see what the TCM looks like. Anyone ever seen or heard anything like this before? It's a 2005 Z51.

 

Sounds like they are guessing. They should go to the diagnostic trouble chart for the codes the system is setting. Those charts will have them check wiring, sensors ... and if nothing in the system is faulty you then replace the control module that controls that system. BCM, ECM... I'm not sure that car has a PCM. My guess would be it needs a BCM.

 

The problem as I understand it is that the corvette has 18 computers in it (according to the mechanic) that are all connected and when one goes it causes the others to not work properly as well causing a multitude of codes to pop up. Wiring has already been checked once. And yes, it has a PCM.

 

Ask him to show you the diagnostic page in the service manual for the PCM. There isn't one. A corvette uses an ECM for the Engine, TCM for the trans, BCM for the body, EBCM for brakes ...

Below is a list of all the available modules for an 05 Corvette, depending on how optioned, you may not have all these.


What codes are you getting? I'll tell you which module is involved with the setting of that code if you'd like. If it's a traction control/active handling code, there are only a couple modules involved with that system - he doesn't need to be concerned with 18 computers.
There are also some bulletins that might help.


Body Control Module
Communication Interface Module (OnStar ®)
Cooling Fan Control Module
Door Control Module
Electronic Brake Control Module
Electronic Suspension Control Module
Engine Control Module
Folding Top Control Module
Heated Seat Control Module
HVAC Control Module
Inflatable Restraint Sensing and Diagnostic Module
Memory Seat Control Module
Remote Control Door Lock Receiver
Steering Column Lock Control Module
Transmission Control Module

 

The dealer said there were 32 codes stored, but I don't have a list of them as of now. I remember seeing a Service Transmission Control Module and lack of BUS Communications. It had multiple codes in multiple modules.

 

Hopefully the technician is following the Service Manual (SI) diagnostics step by step. There is a strategy that must be followed for multiple DTC codes and the service manual spells it out. I'll copy one section below that gives advice from the service manual for multiple DTC's.

You could ask what order are you diagnosing the DTCs? And if he doesn't have a service manual or SI (electronic service manual) right there at his fingertips and says - exactly the way the service manual says to. If not he's just guessing. For multiple codes, you've got to use the strategy the manual tells you to. It will go through all the sensors, wiring, connectors ... which is very time consuming, then ultimately replace the module for that system if nothing else is wrong. Many skip all the important steps and just throw a module at it, playing the odds that might fix it. It might fix it, or just one loose wire somewhere can cause all those codes, and the only way to fix it will be following the book.

From SI=


Important: Do NOT clear any DTCs unless instructed by a diagnostic procedure.


• Diagnose the DTCs in the order that the DTCs appear on the scan tool or mis-diagnosis may occur.

• If multiple powertrain DTCs are stored, diagnose the DTCs in the following order:


Component level DTCs, such as sensor DTCs, solenoid DTCs, and relay DTCs.
System level DTCs, such as misfire DTCs, evaporative emission (EVAP) system DTCs, and fuel trim DTCs.