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.

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HOMESERVICE MANUALSMAZDA20066 I, 4D SEDAN, AUTOMATICREPAIR AND DIAGNOSIS (SINGLE PAGE)BODY & FRAMEDOOR LOCKSON-BOARD DIAGNOSTIC [IMMOBILIZER SYSTEM (WITH ADVANCED KEYLESS SYSTEM)]SECURITY LIGHT: DTC 14 (WDS OR EQUIVALENT: DTC -/B1602)DIAGNOSTIC PROCEDURE

2006 Mazda 6 i, 4D Sedan, Automatic

Diagnostic procedure

2006 Mazda 6 i, 4D Sedan, AutomaticSECTION Diagnostic procedure

DTC B1602 DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	INSPECT FOR OTHER PROPER KEYS Using any other valid key, turn ignition switch to ON position. If there are no other valid keys, then register an additional key using SST (WDS or equivalent) and turn ignition switch to ON position. (See IMMOBILIZER SYSTEM COMPONENT REPLACEMENT/KEY ADDITION AND CLEARING [WITH ADVANCED KEYLESS SYSTEM]. ) Does SST (WDS or equivalent) indicate DTC -/B1602 again?	Yes	Replace coil antenna, then go to next step. (See COIL REMOVAL/INSTALLATION )
1		No	Dispose of defective key. Duplicate key if necessary. (See IMMOBILIZER SYSTEM COMPONENT REPLACEMENT/KEY ADDITION AND CLEARING [WITH ADVANCED KEYLESS SYSTEM]. )
2	INSPECT KEYLESS CONTROL MODULE. Turn the ignition switch to the ON position. Is the DTC displayed? Security light: 14 WDS or equivalent: -/B1602	Yes	Replace keyless control module, then go to the next step. (See KEYLESS CONTROL MODULE REMOVAL/INSTALLATION [WITH ADVANCED KEYLESS SYSTEM]. )
2		No	DTC troubleshooting completed.

RENDER: 1.0x

NO RELATED

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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.