| DTC Code | DTC Name |
|---|---|
| U0100 | Lost Communication with ECM / PCM "A" |
| U0121 | Lost Communication with Anti-lock Brake System (ABS) Control Module |
| U0131 | Lost Communication with Electric Power Steering ECU |
| U0140 | Lost Communication with Main Body ECU |
| U0151 | Lost Communication with Airbag ECU |
| U0155 | Lost Communication with Instrument Panel Cluster Control Module (Combination Meter) |
| U0164 | Lost Communication with HVAC Control Module |
DESCRIPTION
The engine stop and start ECU communicates with the SFI system, ABS/VSC system, EPS, combination meter system, and air conditioning system via CAN. If any of these CAN communication malfunctions occurs, the respective DTC will be stored.
Tech Tips
If the backup boost converter detects overcurrent in a power source circuit, power supply to the circuit is shut off. Therefore a DTC indicating a CAN communication error with the applicable system will be stored in addition to DTC P323B.
Example: If the backup boost converter detects overcurrent in the power source circuit for EPS and the power supply is shut off, DTC U0131 and P323B (Backup Boost Converter) will be stored.
The Controller Area Network (CAN) is a serial data communication system for real time applications. This is a vehicle multiplex communication system which has a high communication speed (500 kbps) and a high level of ability to detect malfunctions. By pairing CANH and CANL bus wires, CAN communication is performed using the voltage differential between the wires.
Tech Tips
Malfunctions in the CAN bus wires can be confirmed using the DLC3. However, if there is an open in the branch wire to the DLC3, malfunctions in the CAN bus wires cannot be detected.
Using the intelligent tester makes it possible to check for CAN communication system DTCs.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| U0100 | No communication between the engine stop and start ECU and the ECM for 0.76 seconds. |
|
| U0121 | No communication between the engine stop and start ECU and the skid control ECU for 2.4 seconds. |
|
| U0131 | No communication between the engine stop and start ECU and the power steering ECU for 0.8 seconds. |
|
| U0140 | No communication between the engine stop and start ECU and the main body ECU for 3.6 seconds. |
|
| U0151 | No communication between the engine stop and start ECU and the center airbag sensor for 10.6 seconds. |
|
| U0155 | No communication between the engine stop and start ECU and the combination meter for 10.6 seconds. |
|
| U0164 | No communication between the engine stop and start ECU and the A/C amplifier for 10.6 seconds. |
|
INSPECTION PROCEDURE
Proceed to CAN Communication System Click here.
Tech Tips
When any DTCs indicating a CAN communication system malfunction are output, troubleshoot the CAN communication system before repairing each corresponding component.