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)ENGINE PERFORMANCESYSTEMON-BOARD DIAGNOSTIC [ENGINE CONTROL SYSTEM L3)DTC P2123NOTES

2006 Mazda 6 i, 4D Sedan, Automatic

DTC P2123: Notes

2006 Mazda 6 i, 4D Sedan, AutomaticSECTION Notes

DTC P2123 DETECTION CONDITION AND POSSIBLE CAUSES

DTC P2123

APP sensor No. 1 circuit high input

DETECTION CONDITION

The PCM monitors the input voltage from APP sensor No. 1 when the engine is running. If the input voltage is above 4.8 ⁽¹⁾ , 4.5 V ⁽²⁾ , the PCM determines that the APP sensor No. 1 circuit input voltage is high.

Diagnostic support note

This is a continuous monitor (CCM).
The MIL illuminates if the PCM detects the above malfunction condition in the first drive cycle.
PENDING CODE is available if the PCM detects the above malfunction condition.
FREEZE FRAME DATA is available.
Are any DTCs is stored in the PCM memory.

POSSIBLE CAUSE

APP sensor No. 1 malfunction
Connector or terminal malfunction
Short to power supply in wiring harness between APP sensor terminal F and PCM terminal 1AO
Open circuit in wiring harness between APP sensor terminal E and PCM terminal 1AS
PCM malfunction

Courtesy of MAZDA MOTORS CORP.

⁽¹⁾	California emission regulation applicable ATX model

⁽²⁾	Except for California emission regulation applicable ATX model

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.