DTC U0402:00 [RADAR UNIT]

id1502a6019300

Description

Error signal received from TCM

Detection condition

•  Communication error between TCM and radar unit

Fail-safe

•  Inhibits the Mazda radar cruise control (MRCC) system control

Possible cause

•  DTCs are stored in the TCM.

―  TCM malfunction

•  Radar unit malfunction

System wiring diagram

Not applicable

Description	Error signal received from TCM
Detection condition	• Communication error between TCM and radar unit
Fail-safe	• Inhibits the Mazda radar cruise control (MRCC) system control
Possible cause	• DTCs are stored in the TCM. ― TCM malfunction • Radar unit malfunction
System wiring diagram	Not applicable

Diagnostic Procedure

Step

Inspection

Action

1

PERFORM DTC INSPECTION FOR TCM

•  Perform the TCM DTC inspection using the M-MDS.
(See ON-BOARD DIAGNOSTIC SYSTEM DTC INSPECTION [TCM (FW6A-EL)].)

(See ON-BOARD DIAGNOSTIC SYSTEM DTC INSPECTION [TCM (GW6A-EL, GW6AX-EL)].)

•  Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [TCM (FW6A-EL)].)

(See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [TCM (GW6A-EL, GW6AX-EL)].)

Go to Step 3.

No

Go to the next step.

2

VERIFY IF MALFUNCTIONING LOCATION IS TCM DEPENDING ON REPEATABILITY

•  Clear radar unit DTCs using the M-MDS.
(See CLEARING DTC [RADAR UNIT].)

•  Switch the ignition ON (engine on).

•  Perform the radar unit DTC inspection using the M-MDS.
(See DTC INSPECTION [RADAR UNIT].)

•  Is the same Pending DTC present?

Yes

Replace the TCM, then go to the next step.

(See CONTROL VALVE BODY REMOVAL/INSTALLATION [FW6A-EL].)

(See CONTROL VALVE BODY REMOVAL/INSTALLATION [GW6A-EL, GW6AX-EL].)

No

Go to Step 4.

3

VERIFY THAT REPAIRS HAVE BEEN COMPLETED

•  Clear radar unit DTCs using the M-MDS.
(See CLEARING DTC [RADAR UNIT].)

•  Switch the ignition ON (engine on).

•  Perform the radar unit DTC inspection using the M-MDS.
(See DTC INSPECTION [RADAR UNIT].)

•  Is the same Pending DTC present?

Yes

Repeat the inspection from Step 1.

•  If the malfunction does not recur, go to the next step.

•  If the malfunction recurs, replace the radar unit.
(See RADAR UNIT REMOVAL/INSTALLATION.)

Go to the next step.

No

Go to the next step.

4

VERIFY THAT NO OTHER DTCs ARE PRESENT

•  Verify other DTCs displayed.

•  Are any other DTCs output?

Yes

Perform the corresponding DTC inspection.

No

DTC troubleshooting completed.

Step	Inspection		Action
1	PERFORM DTC INSPECTION FOR TCM • Perform the TCM DTC inspection using the M-MDS. (See ON-BOARD DIAGNOSTIC SYSTEM DTC INSPECTION [TCM (FW6A-EL)].) (See ON-BOARD DIAGNOSTIC SYSTEM DTC INSPECTION [TCM (GW6A-EL, GW6AX-EL)].) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [TCM (FW6A-EL)].) (See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [TCM (GW6A-EL, GW6AX-EL)].) Go to Step 3.
1		No	Go to the next step.
2	VERIFY IF MALFUNCTIONING LOCATION IS TCM DEPENDING ON REPEATABILITY • Clear radar unit DTCs using the M-MDS. (See CLEARING DTC [RADAR UNIT].) • Switch the ignition ON (engine on). • Perform the radar unit DTC inspection using the M-MDS. (See DTC INSPECTION [RADAR UNIT].) • Is the same Pending DTC present?	Yes	Replace the TCM, then go to the next step. (See CONTROL VALVE BODY REMOVAL/INSTALLATION [FW6A-EL].) (See CONTROL VALVE BODY REMOVAL/INSTALLATION [GW6A-EL, GW6AX-EL].)
2		No	Go to Step 4.
3	VERIFY THAT REPAIRS HAVE BEEN COMPLETED • Clear radar unit DTCs using the M-MDS. (See CLEARING DTC [RADAR UNIT].) • Switch the ignition ON (engine on). • Perform the radar unit DTC inspection using the M-MDS. (See DTC INSPECTION [RADAR UNIT].) • Is the same Pending DTC present?	Yes	Repeat the inspection from Step 1. • If the malfunction does not recur, go to the next step. • If the malfunction recurs, replace the radar unit. (See RADAR UNIT REMOVAL/INSTALLATION.) Go to the next step.
3		No	Go to the next step.
4	VERIFY THAT NO OTHER DTCs ARE PRESENT • Verify other DTCs displayed. • Are any other DTCs output?	Yes	Perform the corresponding DTC inspection.
4		No	DTC troubleshooting completed.