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.
Door Unit
2002 Honda Civic SiSECTION Door Unit
WARNING: This page is about a different car, the 2006 Acura MDX, 2005 Acura MDX, 2004 Acura MDX, and 2003 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.
- Remove the door multiplex control unit, and disconnect its connector.
- Inspect the connector and socket terminals to be sure they are making good contact.
- If the terminals are bent, loose or corroded, repair them as necessary, and recheck the system.
- If the terminals look OK, go to step 3.
- Reconnect the connector to the door multiplex control unit, turn the ignition switch ON (II) to keep the system awake, perform these input tests at the connector.
- If any test indicates a problem, find and correct the cause, then recheck the system.
- If all the input tests prove OK, go to step 4.CONTROL UNIT INPUT TEST (DOOR UNIT)
Cavity Wire Test condition Test: Desired result Possible cause if result is not obtained A1 WHT/YEL Under all conditions Check for voltage to ground:
There should be battery voltage.- Blown No. 13 (7.5 A) fuse in the passenger's under-dash fuse/relay box
- An open in the wire
A12 BLK Under all conditions Check for voltage to ground:
There should be less than 1 V.- Poor ground (G401)
- An open in the wire
A6 BLU/WHT Driver's door key cylinder switch in LOCK Check for voltage to ground:
There should be less than 1 V.- Faulty driver's door key cylinder switch
- Poor ground (G401)
- An open in the wire
- Short to ground
Driver's door key cylinder switch in the neutral position Check for voltage to ground:
There should be 5 V or more.Driver's door key cylinder switch in UNLOCK Check for voltage to ground:
There should be 5 V or more.A16 BLU Driver's door key cylinder switch in UNLOCK Check for voltage to ground:
There should be less than 1 V.- Faulty driver's door key cylinder switch
- Poor ground (G401)
- An open in the wire
- Short to ground
Driver's door key cylinder switch in the neutral position Check for voltage to ground:
There should be 5 V or more.Driver's door key cylinder switch in LOCK Check for voltage to ground:
There should be 5 V or more.A7 PNK Driver's door lock knob locked Check for voltage to ground:
There should be less than 1 V.- Faulty driver's door lock actuator
- Poor ground (G401)
- An open in the wire
Driver's door lock knob unlocked Check for voltage to ground:
There should be 5 V or more.- Faulty driver's door lock actuator
- Short to ground in the wire
A17 BLK/RED Driver's door lock knob unlocked Check for voltage to ground:
There should be less than 1 V.- Faulty driver's door lock actuator
- Poor ground (G401)
- An open in the wire
Driver's door lock knob locked Check for voltage to ground:
There should be 5 V or more.- Faulty driver's door lock actuator
- Short to ground in the wire
A8 BLK/WHT Driver's door lock switch in LOCK Check for voltage to ground:
There should be less than 1 V.- Faulty driver's door lock switch
- Poor ground (G401)
- An open in the wire
Driver's door lock switch in the neutral position Check for voltage to ground:
There should be 5 V or more.- Faulty driver's door lock switch
- Short to ground in the wire
A18 GRN/RED Driver's door lock switch in UNLOCK Check for voltage to ground:
There should be less than 1 V.- Faulty driver's door lock switch
- Poor ground (G401)
- An open in the wire
Driver's door lock switch in the neutral position Check for voltage to ground:
There should be 5 V or more.- Faulty driver's door lock switch
- Short to ground in the wire
- If all the input tests prove OK, one of the control units must be faulty, substitute a known-good control unit for the one that is most likely at fault, then recheck the system. If the system works properly, the original control unit is faulty; replace it. If there is still a malfunction, substitute a known-good control unit for the next most likely unit to be at fault, and recheck. If the system works properly, the original unit is faulty; replace it.
RENDER: 1.0x
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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.