DTC C1A77:12/C1A77:13/C1A77:16 [DYNAMIC STABILITY CONTROL (DSC)]

id0402b2880000

DTC
C1A77:12/C1A77:13/C1A77:16
Valve relay
DETECTION CONDITION
•  C1A77:12
―  Valve relay in DSC HU/CM stuck ON when switched the ignition to ON, valve relay OFF is commanded.
•  C1A77:13/C1A77:16
―  Valve relay in DSC HU/CM stuck OFF when valve relay ON is commanded.
FAIL-SAFE FUNCTION
•  Illuminates the ABS warning light, brake system warning light, TCS/DSC indicator light, and master warning light*1.
•  Inhibits the ABS, EBD, brake assist, TCS, Hill Launch Assist (HLA), vehicle roll prevention function*2, DSC, Mazda Radar Cruise Control (MRCC)*2, Smart Brake Support (SBS)*2, Smart City Brake Support (SCBS)*2, and Secondary Collision Reduction (SCR)*2.
*1: Vehicles with Smart City Brake Support (SCBS), Mazda Radar Cruise Control (MRCC) and/or Smart Brake Support (SBS).
*2: If equipped.
POSSIBLE CAUSE
•  Malfunction of fuse (ABS/DSC S 30A)
•  Open circuit in harness between DSC HU/CM terminal AG and battery positive terminal
•  Open circuit or short of valve relay in DSC HU/CM
•  Stuck valve relay in DSC HU/CM

Diagnostic procedure

STEP

INSPECTION

ACTION
1
INSPECT DSC FUSE CONDITION
•  Is DSC fuse (ABS/DSC S 30A) normal?
Yes
Go to the next step.
No
Replace the fuse, then go to Step 3.
2
INSPECT VALVE RELAY POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT
•  Switch the ignition to off.
•  Disconnect DSC HU/CM connector.
•  Switch the ignition to ON (engine off).
•  Measure voltage between DSC HU/CM terminal AG (harness-side) and ground.
•  Is voltage B+?
Yes
Go to the next step.
No
Refer to the wiring diagram and verify whether or not there is a common connector between battery positive terminal and DSC HU/CM terminal AG.
If there is a common connector:
•  Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
•  Repair or replace the malfunctioning part.
If there is no common connector:
•  Repair or replace the wiring harness which has an open circuit.
Go to next step.
3
VERIFY TROUBLESHOOTING COMPLETED
•  Reconnect all disconnected connectors.
•  Clear the DTC from the memory.
•  Is same DTC present?
Yes
Replace DSC HU/CM, then go to the next step.
(See DSC HU/CM REMOVAL/INSTALLATION.)
No
Go to the next step.
4
VERIFY AFTER REPAIR PROCEDURE
•  Is there any other DTC present?
Yes
Go to the applicable DTC inspection.
(See ON-BOARD DIAGNOSIS [DYNAMIC STABILITY CONTROL (DSC)].)
No
Troubleshooting completed.