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.
2007 Mazda 3 L4-2.0LFACTORY OEM SERVICE PROCEDURE
Body Control Systems: Testing and Inspection
PROCEDURES FOR DETERMINING THE LOCATION OF A MALFUNCTION[MULTIPLEX COMMUNICATION SYSTEM]
System Wiring Diagram
PCM
1. Inspect the display of DTC U0101, U0121 and/or U0155, using the M-MDS. (See DTC TABLE [MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
TCM
1. Inspect the display of DTC U0100 using the M-MDS. (See DTC TABLE[MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
EHPAS Control Module
1. Inspect the display of DTC U0100 and/or U2023, using the M-MDS. (See DTC TABLE[MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
DSC HU/CM or ABS HU/CM
1. Inspect the display of DTC U1900, U2202 and/or U2523, using the M-MDS. (See DTC TABLE [MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
Instrument Cluster
1. Inspect the display of DTC U0100, U0101, U0121, U0127 and/or U0131 using the M-MDS. (See DTC TABLE[MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
3. Inspect the display of DTC U0140, U0151 and/or U0184, using the M-MDS. (See DTC TABLE[MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
4. Referring to the above table, determine the malfunctioning part of the CAN system.
Climate Control Unit
1. Inspect the display of DTC U0140, U0155 and/or U0184, using the M-MDS. (See DTC TABLE [MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
SAS Control Module
1. Inspect the display of DTC U1900 using the M-MDS. (See DTC TABLE [MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
Information Display
1. Inspect the display of DTC U0164, U0181 and/or U0184 using the M-MDS. (See DTC TABLE [MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
PJB
1. Inspect the display of DTC U1900 using the M-MDS. (See DTC TABLE [MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
Repair Procedure
1. Inspect the connector of malfunctioning module.
- If there is any malfunction, repair or replace the connector.
2. Inspect the malfunctioning wiring harnesses as follow:
- If there is any malfunction, repair or replace the wiring harnesses.
- If there is no malfunction, replace the malfunctioning module.
- Short to GND
- Short to power supply
- Twisted pair short each other
- Open circuit
3. Make sure to reconnect all disconnected connectors.
4. Clear the CAN system related DTCs using the M-MDS.
5. Verify if the CAN system related DTCs are displayed using the M-MDS.
- If the same following DTCs are present, replace the malfunctioning module.
- U0073 (PCM, TCM, EHPAS control module, TPMS control module, instrument cluster, climate control unit, SAS control module)
- U0516 (TPMS control module, climate control unit)
- U1900(PJB)
- U2012 (DSC HU/CM, ABS HU/CM)
- U2516 (Instrument cluster)
- If other DTC is present, perform the appropriate DTC inspection. (See DTC TABLE[MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
System Wiring Diagram:
System Wiring Diagram
PCM
1. Inspect the display of DTC U0101, U0121 and/or U0155, using the M-MDS. (See DTC TABLE [MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
TCM
1. Inspect the display of DTC U0100 using the M-MDS. (See DTC TABLE[MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
EHPAS Control Module
1. Inspect the display of DTC U0100 and/or U2023, using the M-MDS. (See DTC TABLE[MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
DSC HU/CM or ABS HU/CM
1. Inspect the display of DTC U1900, U2202 and/or U2523, using the M-MDS. (See DTC TABLE [MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
Instrument Cluster
1. Inspect the display of DTC U0100, U0101, U0121, U0127 and/or U0131 using the M-MDS. (See DTC TABLE[MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
3. Inspect the display of DTC U0140, U0151 and/or U0184, using the M-MDS. (See DTC TABLE[MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
4. Referring to the above table, determine the malfunctioning part of the CAN system.
Climate Control Unit
1. Inspect the display of DTC U0140, U0155 and/or U0184, using the M-MDS. (See DTC TABLE [MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
SAS Control Module
1. Inspect the display of DTC U1900 using the M-MDS. (See DTC TABLE [MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
Information Display
1. Inspect the display of DTC U0164, U0181 and/or U0184 using the M-MDS. (See DTC TABLE [MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
PJB
1. Inspect the display of DTC U1900 using the M-MDS. (See DTC TABLE [MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
2. Referring to the above table, determine the malfunctioning part of the CAN system.
Repair Procedure
1. Inspect the connector of malfunctioning module.
- If there is any malfunction, repair or replace the connector.
2. Inspect the malfunctioning wiring harnesses as follow:
- If there is any malfunction, repair or replace the wiring harnesses.
- If there is no malfunction, replace the malfunctioning module.
- Short to GND
- Short to power supply
- Twisted pair short each other
- Open circuit
3. Make sure to reconnect all disconnected connectors.
4. Clear the CAN system related DTCs using the M-MDS.
5. Verify if the CAN system related DTCs are displayed using the M-MDS.
- If the same following DTCs are present, replace the malfunctioning module.
- U0073 (PCM, TCM, EHPAS control module, TPMS control module, instrument cluster, climate control unit, SAS control module)
- U0516 (TPMS control module, climate control unit)
- U1900(PJB)
- U2012 (DSC HU/CM, ABS HU/CM)
- U2516 (Instrument cluster)
- If other DTC is present, perform the appropriate DTC inspection. (See DTC TABLE[MULTIPLEX COMMUNICATION SYSTEM].) Diagnostic Trouble Code Descriptions
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
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.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
Comes to youSame-day available12-month warranty
Get a Free QuoteNo obligation. See pricing before you book.