|WABCO C TYPE (P38 NRR) - System Overview|
|This family of ABS ECU's, denoted C type, have common characteristic in the diagnostic element of their design. This is that once they have been communicated with diagnostically and then put to sleep they inhibit the communication with other ECUs sharing the same data bus and even with themselves. To re-establish diagnostic communication, the ignition must be turned off for approximately five seconds.
It is only possible to communicate with the ABS ECU when the system is in its idle state, that is with the ignition on and the engine running or not. Once the ECU has detected a signal from all sensors that indicates each one has exceeded 2km/h the ECU turns off the dash lamp and exits diagnostic mode. All ECU resources are then used to monitor the sensors and diagnostic communication is no longer possible until the ignition supply has been disconnected and then re-connected.
Despite sharing a common communication standard which means they all start communicating the same, and share some very basic features, these ECUís are actually laid out very differently in respect of their memory usage meaning codes read from one ECU with the wrong program may give incorrect meaning and other codes may not be shown. Also some of them actually require each memory location used for the fault code storage to be re programmed to 0 individually. This means that using the wrong module on an ECU can alter the ECU and make it non functional, re using the right module after will not correct this. So although the ECUís look identical to that used in other vehicles of the same age and can be plugged in, they are NOT diagnostically interchangeable.
|SM021 - WABCO C TYPE (P38 NRR) - System Help file|
|WABCO C TYPE (P38 NRR) - Known Fitments|
|Vehicle makes, models and variants known or believed to be using this vehicle system, required diagnostic lead and degree of known compatibility.
|WABCO C TYPE (P38 NRR) - Physical Details|
|WABCO C TYPE (P38 NRR) - Pin Outs|
|Details of the pin usage for the ECU connector.
|SM021 - WABCO C TYPE (P38 NRR) - Diagnostic Capabilities (Read Fault Codes)|
|This ABS system can self-detect up to 88 faults. These are an even mix of major faults which are safety related, causing full system shutdown and the warning light to illuminate and minor faults caused by flat batteries, power having been temporarily lost.|
|SM021 - WABCO C TYPE (P38 NRR) - Diagnostic Capabilities (Clear Fault Codes)|
|This function first reads the fault code memory to ensure that there are faults to clear and if there are completely erases and clears the fault code memory. Having deleted the faults it then re-checks the fault memory to check that it is clear, reporting success if it is. Failure to clear the fault memory successfully is usually due to the system re-logging the fault the moment the fault memory is clear. This indicates that the fault has not been rectified properly and as far as the system is concerned still exists. A re-check for successful clearing of the fault code memory may be successful but then the system may re-log the fault shortly after.|
|SM021 - WABCO C TYPE (P38 NRR) - Diagnostic Capabilities (Settings)|
|Values, configuration settings, and other stored information which can be read from the ECU, edited and then rewritten back. Read settings can also be stored as a standard HTML page for reference. These pages can then later be re loaded and re written back to the ECU. Please note that some values may be read only due to the fact that they are supplied from the ECUís ROM or are internally calculated.
|SM021 - WABCO C TYPE (P38 NRR) - Diagnostic Capabilities (Inputs)|
|Realtime live display of the information the electronic control unit of the selected vehicle system is currently deriving from its input sensors. The ECU will stop communicating at a speed over 1.6mph (2km/h).
|SM021 - WABCO C TYPE (P38 NRR) - Diagnostic Capabilities (Outputs)|
|Choice of outputs that can be tested.
|SM021 - WABCO C TYPE (P38 NRR) - Diagnostic Capabilities (Other)|
|Choice of functions that can be performed.