As vehicle options have increased, so has the complexity of these options and their control systems. Electronic Control Units (ECUs) must support multiple functions within the vehicle’s electrical system. In years past, manufacturers have introduced several variations (multiple part numbers) of each ECU to support the various vehicle grades.

Having multiple combinations of one part introduced several challenges to manufacturers and significantly increased vehicle cost due to the administrative challenge of managing the various components. To address this issue, part manufacturers introduced ECUs that can support various vehicle options creating a “one-part-fits-all” alternative.

With one-part-fits-all, the part number for an ECU will be the same for all vehicle grades. However, to match the ECU to the vehicle, the ECU must be set up to function with the setting values that are equipped on a particular vehicle. This process is known as configuration.

The BCM is the most common ECU that requires configuration. Examples of vehicle options that are configurable within the BCM are: Intelligent Key (with or without), Power Back Door (with or without), and Auto Headlamps (mode). There are many other configurable options within the various ECUs in vehicles today.

IMPORTANT: If you are working on a system that has a configurable ECU, the technician must use CONSULT-III plus (C-III plus) to perform configuration anytime the ECU is replaced.

Although ECU configuration can be done anytime, it rarely needs to be done unless the ECU is being replaced.

An ECU can be configured using the “Manual” method or the “Read/Write” method. Both methods are performed using C-III plus. The Read/Write method is recommended. It is the best process for configuring the new ECU properly.

BASIC STEPS FOR USING THE READ/WRITE METHOD:

1. Before removing the old ECU, its configuration is “read” and stored in C-III plus under the Vehicle Identification Number (VIN).

2. Once the configuration is stored, the next step is to install the new ECU.

3. Once the new ECU is installed, the configuration that was stored (read) from the old ECU is then downloaded (written) into the new ECU.

Examples of systems that have configurable ECUs: IPDM E/R, CAN GATEWAY, TPMS, and BCM.

BCM CONFIGURATION SCREEN

IMPORTANT: Check ASIST for any TSBs that may be related to the specific system you are working on. From time to time, TSBs are published that give helpful information for various ECU configuration settings that must be performed.

BASIC STEPS FOR USING THE “MANUAL” METHOD:

If the old ECU cannot be read with C-III plus, install the new ECU and then select “Manual Configuration.” The technician must then manually select the correct settings for that particular vehicle.

IMPORTANT NOTE: The Manual configuration must be executed even if all of the settings are already set correctly. There is some information that must be configured (written) into the new ECU that is not listed on the C-III plus screen.

When performing “Manual Configuration,” thoroughly read and understand the vehicle specification. The new ECU may not operate correctly if the incorrect setting values are selected. If there is only one item listed for a particular “Setting Value,” it means there is only one choice for that option on that vehicle.

When replacing a configurable ECU, always perform configuration (“Read/Write” or “Manual”). In some cases (such as many BCMs), there is configuration information that must be downloaded into the new ECU that is not listed (not visible) on the C-III plus screen.

For example, an ECU is replaced; the technician reviews the configurable settings under “Manual Configuration” and notes that they are all set correctly. The technician may assume that executing configuration is not needed because the settings are already correct, but that assumption would be wrong. Configuration must be executed on all configurable ECUs when they are replaced.

For ECU replacement use “Read/Write Configuration.” The original ECU’s configuration is stored in C-III plus, and then “written” or transferred into the new ECU.

Use “Manual Configuration” if the original configuration is lost or not accessible (such as a damaged ECU) and was not stored in C-III plus prior to the replacement.

Progress bar indicates that configuration data is being written into the new control unit.

WAS THE CONFIGURATION PERFORMED CORRECTLY?

To ensure that the configuration was successful, check the systems operated by the new ECU. Check for proper component function compared to the settings (configuration) that were performed. If the component responds appropriately, the configuration was successful.

IF CONFIGURATION IS NOT PERFORMED CORRECTLY

In the event that the configuration is not performed or not performed correctly, the ECU may be partially inoperative.

This depends solely on the system that was incorrectly set. Typical errors observed are CAN-related messaging such as U1000 where a part is not communicating with other modules in the vehicle. One example is the power back door; if the BCM is not configured “WITH PBD,” the result would be that control switches used to operate the power back door will not function when pressed.

When using Manual Configuration, there are some setting values that are configured “automatically” for the specific vehicle. C-III Plus will download both Manual Configuration (setting values selected by the technician) and “Automatic Configuration” (automatic setting values for the specific vehicle) at the same time when the write configuration command is executed.

NOTE: Always make sure to select “OK” EVEN if the indicated configuration items list is blank, or the brand new control module lists the same items as the desired configuration. If “OK” is not selected, configuration WILL NOT be performed correctly as the value settings that aren’t visible will not be configured to the new ECU.