DTC U0402:00 [DYNAMIC STABILITY CONTROL (DSC)]

id0402b2881800

DTC
U0402:00
Abnormal message from transmission/transaxle
DETECTION CONDITION
•  The DSC HU/CM received error signals from the transmission/transaxle for 1 s or more with the ignition switched ON (engine off or on).
FAIL-SAFE FUNCTION
•  Illuminates the TCS/DSC indicator light, Mazda Radar Cruise Control (MRCC) warning light*1, and Smart Brake Support/Smart City Brake Support (SBS/SCBS) indicator light (amber)*1.
•  Tire pressure monitoring system warning light*1 illuminates after flashes.
•  Inhibits the TCS, DSC, vehicle roll prevention function*1, Hill Launch Assist (HLA), TPMS*1, Secondary Collision Reduction (SCR)*1, Mazda Radar Cruise Control (MRCC)*1, Smart Brake Support (SBS)*1, and Smart City Brake Support (SCBS)*1 controls.
*1: If equipped.
POSSIBLE CAUSE
•  The transmission/transaxle could not send a normal signal temporarily. (DTCs are stored in the TCM (Except MZR 1.6)/PCM (MZR 1.6).)
•  PCM or TCM malfunction
SYSTEM WIRING DIAGRAM
Not applicable

Diagnostic procedure

STEP

INSPECTION

ACTION
1
VERIFY DTCs FOR TCM or PCM
•  Switch the ignition to off.
•  Verify DTCs for the TCM or PCM using the M-MDS.
•  Is the DTC displayed?
Yes
Repair the malfunctioning part according to the applicable DTC troubleshooting.
(See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [FN4A-EL].)
(See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [CW6A-EL].)
(See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [FW6A-EL].)
(See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [EW6A-EL].)
(See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [GW6A-EL].)
No
Go to the next step.
2
VERIFY THAT THE SAME DTC IS NOT PRESENT
•  Clear DTC for the DSC HU/CM using the M-MDS.
•  Are the same DTCs present?
Yes
Repeat the inspection from Step 1.
If the malfunction recurs, replace the TCM or PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION [FN4A-EL].)
(See CONTROL VALVE BODY REMOVAL/INSTALLATION [CW6A-EL].)
(See CONTROL VALVE BODY REMOVAL/INSTALLATION [FW6A-EL].)
(See CONTROL VALVE BODY REMOVAL/INSTALLATION [EW6A-EL].)
(See CONTROL VALVE BODY REMOVAL/INSTALLATION [GW6A-EL].)
No
Go to the next step.
3
VERIFY IF OTHER DTCs DISPLAYED
•  Are any other DTCs displayed?
Yes
Repair the malfunctioning part according to the applicable DTC troubleshooting.
(See ON-BOARD DIAGNOSIS [DYNAMIC STABILITY CONTROL (DSC)].)
No
DTC troubleshooting completed.