U2100
DTC U2100
CIRCUIT DESCRIPTION
The controller area network (CAN) serial data line is a high speed serial data bus used to communicate information between the engine control module (ECM), body control module (BCM), and the transmission control module (TCM). Typical data-transmission speeds must be high enough to ensure that the required real-time response is maintained. The CAN serial data line does not communicate with the scan tool via the data link connector (DLC). CAN serial data information is interpreted by the BCM and transmitted to the serial data line by the BCM.
Modules connected to the CAN serial data circuit monitors communication during normal vehicle operation, where operation information is exchanged among the modules. Each module on the CAN network maintains a transmit error counter (TEC) and a receive error counter (REC). The counter values increase with detected errors and will decrease with error-free messages. If the TEC value exceeds 255, the controller removes itself for the network and DTC U2100 will result.
DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC U2100 Controller Area Network (CAN) Bus Communication
CONDITIONS FOR RUNNING THE DTC
- Supply voltage to the modules that are in the normal operating range.
- The vehicle is in the RUN power mode.
CONDITIONS FOR SETTING THE DTC
The module setting the DTC has attempted to establish communications on the CAN circuits more than 7 times.
ACTION TAKEN WHEN THE DTC SETS
- The ECM turns ON the malfunction indicator lamp (MIL) during the second consecutive drive cycle with the error detected.
- The ECM records the operating conditions at the time of turning ON the MIL and stores the data as Freeze Frame information.
CONDITIONS FOR CLEARING THE MIL/DTC
- A current DTC Last Test Failed clears when the diagnostic runs and passes after 3 consecutive drive cycles.
- A current DTC clears and the MIL is turned OFF when the fault is no longer present.
- A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the fault, or after 40 consecutive drive cycles.
TEST
