Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2021 Mazda 3 BaseFACTORY OEM SERVICE PROCEDURE
DSC HU/Control Module INSPECTION
- Disconnect the DSC HU/Control Module connector. (See DSC HU/Control Module REMOVAL/INSTALLATION [L.H.D. (US)] .)
- Connect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .)
- Attach the tester lead to the DSC HU/Control Module wiring harness-side connector and inspect the voltage, continuity, or resistance according to the standard (reference) on the table.
Standard (Reference)
-: Not applicable
VOLTAGE, CONTINUITY, RESISTANCE - STANDARD DESCRIPTION
| Terminal | Signal name | Connected to | Measured item | Measured terminal (measurement condition) | Standard | Inspection item(s) |
|---|---|---|---|---|---|---|
| A | Ground | Ground point | Continuity | A-Ground point | Continuity detected |
|
| B | - | - | - | - | - | - |
| C | Electric parking brake motor gear unit (LH) | Electric parking brake motor gear unit (LH) | Continuity | C-Electric parking brake motor gear unit (LH) terminal B | Continuity detected |
|
| D | - | - | - | - | - | - |
| E | - | - | - | - | - | - |
| F | - | - | - | - | - | - |
| G | - | - | - | - | - | - |
| H | Electric parking brake motor gear unit (LH) | Electric parking brake motor gear unit (LH) | Continuity | H -Electric parking brake motor gear unit (LH) terminal A | Continuity detected |
|
| I | Brake fluid level sensor | Brake fluid level sensor | Continuity | I - brake fluid level sensor terminal A | Continuity detected |
|
| J | CAN1_L | CAN module | This terminal is used for communication and cannot be used for malfunction determination during terminal voltage inspection. Perform a DTC inspection. | |||
| K | - | - | - | - | - | - |
| L | CAN1_H | CAN module | This terminal is used for communication and cannot be used for malfunction determination during terminal voltage inspection. Perform a DTC inspection. | |||
| M | RR wheel-speed sensor (+) | ABS wheel-speed sensor (RR) | Continuity | M -ABS wheel-speed sensor (RR) terminal B | Continuity detected |
|
| N | - | - | - | - | - | - |
| O | - | - | - | - | - | - |
| P | RR wheel-speed sensor (-) | ABS wheel-speed sensor (RR) | Continuity | P-ABS wheel-speed sensor (RR) terminal D | Continuity detected |
|
| Q | - | - | - | - | - | - |
| R | Stop signal | Electrical supply unit | Continuity | R-Electrical supply unit terminal 3L | Continuity detected |
|
| S | LF wheel-speed sensor (+) | ABS wheel-speed sensor (LF) | Continuity | S-ABS wheel-speed sensor (LF) terminal B | Continuity detected |
|
| T | - | - | - | - | - | - |
| U | - | - | - | - | - | - |
| V | LF wheel-speed sensor (-) | ABS wheel-speed sensor (LF) | Continuity | V-ABS wheel-speed sensor (LF) terminal A | Continuity detected |
|
| W | Electric parking brake switch | Electric parking brake switch | Continuity | W-Electric parking brake switch terminal H | Continuity detected |
|
| X | - | - | - | - | - | - |
| Y | LR wheel-speed sensor (+) | ABS wheel-speed sensor (LR) | Continuity | Y-ABS wheel-speed sensor (LR) terminal B | Continuity detected |
|
| Z | - | - | - | - | - | - |
| AA | - | - | - | - | - | - |
| AB | LR wheel-speed sensor (-) | ABS wheel-speed sensor (LR) | Continuity | AB-ABS wheel-speed sensor (LR) terminal D | Continuity detected |
|
| AC | - | - | - | - | - | - |
| AD | Electric parking brake switch indicator light | Electric parking brake switch indicator light (built into electric parking brake switch) | Continuity | AD-Electric parking brake switch terminal F | Continuity detected |
|
| AE | RF wheel-speed sensor (+) | ABS wheel-speed sensor (RF) | Continuity | AE-ABS wheel-speed sensor (RF) terminal B | Continuity detected |
|
| AF | Electric parking brake switch | Electric parking brake switch | Continuity | AF-Electric parking brake switch terminal E | Continuity detected |
|
| AG |
Power supply (system) | IG1 relay No. 2 | Voltage | Ignition switched ON (engine off). | B+ |
|
| Switch the ignition off. | 1 V or less | |||||
| AH | RF wheel-speed sensor (-) | ABS wheel-speed sensor (RF) | Continuity | AH-ABS wheel-speed sensor (RF) terminal A | Continuity detected |
|
| AI | Electric parking brake switch | Electric parking brake switch | Continuity | AI-Electric parking brake switch terminal I | Continuity detected |
|
| AJ | - | - | - | - | - | - |
| AK | Electric parking brake motor gear unit (RH) | Electric parking brake motor gear unit (RH) | Continuity | AK-Electric parking brake motor gear unit (RH) terminal A | Continuity detected |
|
| AL | Electric parking brake switch | Electric parking brake switch | Continuity | AL-Electric parking brake switch terminal D | Continuity detected |
|
| AM | - | - | - | - | - | - |
| AN | CAN2_L | CAN module | This terminal is used for communication and cannot be used for malfunction determination during terminal voltage inspection. Perform a DTC inspection. | |||
| AO | - | - | - | - | - | - |
| AP | Electric parking brake motor gear unit (RH) | Electric parking brake motor gear unit (RH) | Continuity | AP-Electric parking brake motor gear unit (RH) terminal B | Continuity detected |
|
| AQ | CAN2_H | CAN module | This terminal is used for communication and cannot be used for malfunction determination during terminal voltage inspection. Perform a DTC inspection. | |||
| AR | - | - | - | - | - | - |
| AS | Power supply (pump motor operation) | Battery | Voltage | Under any condition | B+ |
|
| AT | Power supply (solenoid operation) | Battery | Voltage | Under any condition | B+ |
|
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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