Mazda DTC P0071 Diagnostic

DTC P0071	Ambient air thermistor circuit failure
DETECTION CONDITION	Open circuit or short to power supply or GND in wiring harness between PJB and ambient temperature sensor
POSSIBLE CAUSE	• Open circuit in wiring harness between PJB terminal J-02 AD and ambient temperature sensor terminal A • Open circuit in wiring harness between PJB terminal J-02 AF and ambient temperature sensor terminal B • Short to power supply in wiring harness between PJB terminal J-02 AD and ambient temperature sensor terminal A • Short to GND in wiring harness between PJB terminal J-02 AD and ambient temperature sensor terminal A • Ambient temperature sensor circuit short each other • Ambient temperature sensor malfunction • PJB malfunction

DTC P0071

Ambient air thermistor circuit failure

DETECTION CONDITION

Open circuit or short to power supply or GND in wiring harness between PJB and ambient temperature sensor

POSSIBLE CAUSE

• Open circuit in wiring harness between PJB terminal J-02 AD and ambient temperature sensor terminal A

• Open circuit in wiring harness between PJB terminal J-02 AF and ambient temperature sensor terminal B

• Short to power supply in wiring harness between PJB terminal J-02 AD and ambient temperature sensor terminal A

• Short to GND in wiring harness between PJB terminal J-02 AD and ambient temperature sensor terminal A

• Ambient temperature sensor circuit short each other

• Ambient temperature sensor malfunction

• PJB malfunction

Diagnostic procedure


STEP	INSPECTION		ACTION
1	INSPECT AMBIENT TEMPERATURE SENSOR CONNECTOR • Turn the ignition switch off. • Disconnect the ambient temperature sensor connector. • Inspect the ambient temperature sensor connector terminals for poor connection (such as damaged/pulled-out pins, and corrosion). • Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 8.
1		No	Go to the next step.
2	INSPECT PJB CONNECTOR • Disconnect the PJB connector. • Inspect the PJB connector terminals for poor connection (such as damaged/pulled-out pins, and corrosion). • Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 8.
2		No	Go to the next step.
3	INSPECT AMBIENT TEMPERATURE SENSOR CIRCUIT FOR OPEN CIRCUIT • Inspect for continuity between following terminals: – PJB terminal J-02 AD (wiring harness-side) – ambient temperature sensor terminal A (wiring harness-side) – PJB terminal J-02 AF (wiring harness-side) – ambient temperature sensor terminal B (wiring harness-side) • Is there continuity?	Yes	Go to the next step.
3		No	Repair or replace the wiring harness for a possible open circuit, then go to Step 8.
4	INSPECT AMBIENT TEMPERATURE SENSOR SIGNAL CIRCUIT FOR SHORT TO GND • Inspect for continuity between PJB terminal J-02 AD (wiring harness-side) and body GND. • Is there continuity?	Yes	Repair or replace the wiring harness for a possible short to GND, then go to Step 8.
4		No	Go to the next step.
5	INSPECT AMBIENT TEMPERATURE SENSOR SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY • Turn the ignition switch to the ON position (Engine off). • Measure the voltage between PJB terminal J-02 AD (wiring harness-side) and body GND. • Is the voltage B+?	Yes	Repair or replace the wiring harness for a possible short to power supply, then go to Step 8.
5		No	Go to the next step.
6	INSPECT AMBIENT TEMPERATURE SENSOR CIRCUIT FOR SHORT EACH OTHER • Turn the ignition switch to the LOCK position. • Inspect for continuity between ambient temperature sensor terminals A and B (wiring harness-side). • Is there continuity?	Yes	Repair or replace the wiring harness for a possible short each other, then go to Step 8.
6		No	Go to the next step.
7	INSPECT AMBIENT TEMPERATURE SENSOR • Inspect the ambient temperature sensor. • Is there any malfunction?	Yes	Replace the ambient temperature sensor, then go to the next step.
7		No	Go to the next step.
8	VERIFY TROUBLESHOOTING COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PJB memory using the WDS or equivalent. • Perform the self-test. • Is the same DTC present?	Yes	Replace the PJB.
8		No	Troubleshooting completed.