DTC U0001 (Flash Code 84) High Speed CAN Communication Bus (RZ4E-TC)

1. DTC U0001 description

Models with radar sensors/stereo cameras

The ECM, battery sensor, TCCM, rear differential lock control unit, TCM, information module, DRM, and central gateway control unit communicate the control information and diagnosis information via the CAN communication circuit. The ECM monitors the CAN operational status by expecting a constant message flow from each module. If the ECM fails to receive an expected message, the DTC is set.

Models without radar sensors and stereo cameras

The ECM, battery sensor, TCCM, rear differential lock control unit, EHCU, parking aid system control unit, TCM, steering angle sensor, SRS control unit, control panel, BCM, wireless access module, DRM, headlight auto leveling control unit, information module, eCall unit, audio center unit, and instrument panel cluster communicate the control information and diagnosis information via the CAN communication circuit. The ECM monitors the CAN operational status by expecting a constant message flow from each module. If the ECM fails to receive an expected message, the DTC is set.

2. Condition for setting DTC U0001

Condition for running the DTC

The battery voltage is 9 to 16 V.
The ignition voltage is 9 to 16 V.
The ignition switch is ON.

Condition for setting the DTC

The ECM detects a CAN Bus OFF status.

3. Action taken when DTC U0001 sets

Euro4: The ECM illuminates the MIL. Refer to Action taken when DTC sets - Type A (Euro4).
Except Euro4: The ECM illuminates the check engine warning light. Refer to Action taken when DTC sets - Type A (Except Euro4).

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) DTC type definitions".

The ECM limits the fuel injection quantity.
The ECM inhibits the cruise control.

4. Condition for clearing DTC U0001

Euro4: Refer to Condition for clearing the MIL/DTC - Type A or Type B (Euro4).
Except Euro4: Refer to Condition for clearing the check engine warning light/DTC - Type A or Type B (Except Euro4).

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) DTC type definitions".