DTC P0073:00 [MZR 1.6]

id0102h3146000

DTC P0073:00

Ambient temperature sensor circuit high input
DETECTION CONDITION
•  The PCM monitors the input signal from the ambient temperature sensor. If the voltage from the ambient temperature sensor is above 4.84 V, the PCM determines that the ambient temperature sensor circuit has a malfunction.
Diagnostic support note
•  This is a continuous monitor (other).
•  The check engine light does not illuminate.
•  FREEZE FRAME DATA (Mode 2)/Snapshot data is not available.
•  DTC is stored in the PCM memory.
FAIL-SAFE FUNCTION
Not applicable
POSSIBLE CAUSE
•  Ambient temperature sensor connector or terminals malfunction
•  Ambient temperature sensor malfunction
•  PCM connector or terminals malfunction
•  Short to power supply in wiring harness between ambient temperature sensor terminal A and PCM terminal 1AL
•  Open circuit in wiring harness between the following terminals:
―  Ambient temperature sensor terminal A—PCM terminal 1AL
―  Ambient temperature sensor terminal B—PCM terminal 1AN
•  PCM malfunction

Diagnostic Procedure

STEP

INSPECTION

ACTION
1
VERIFY RELATED SERVICE INFORMATION AVAILABILITY
•  Verify related Service Information availability.
•  Is any related Service Information available?
Yes
Perform repair or diagnosis according to the available Service Information.
•  If the vehicle is not repaired, go to the next step.
No
Go to the next step.
2
INSPECT AMBIENT TEMPERATURE SENSOR CONNECTOR CONDITION
•  Switch the ignition off.
•  Disconnect the ambient temperature sensor connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is there any malfunction?
Yes
Repair or replace the connector and/or terminals, then go to Step 7.
No
Go to the next step.
3
INSPECT AMBIENT TEMPERATURE SENSOR
•  Inspect the ambient temperature sensor.
•  Is there any malfunction?
Yes
Replace the ambient temperature sensor, then go to Step 7.
(See AMBIENT TEMPERATURE SENSOR REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER].)
(See AMBIENT TEMPERATURE SENSOR REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].)
No
Go to the next step.
4
INSPECT PCM CONNECTOR CONDITION
•  Disconnect the PCM connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is there any malfunction?
Yes
Repair or replace the connector and/or terminals, then go to Step 7.
No
Go to the next step.
5
INSPECT AMBIENT TEMPERATURE SENSOR SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY
•  Verify that the ambient temperature sensor and PCM connectors are disconnected.
•  Switch the ignition ON (engine off).
Note
•  Another DTC may be stored by the PCM detecting an open circuit.
•  Measure the voltage at the ambient temperature sensor terminal A (wiring harness-side).
•  Is the voltage 0 V?
Yes
Go to the next step.
No
Refer to the wiring diagram and verify whether or not there is a common connector between ambient temperature sensor terminal A and PCM terminal 1AL.
If there is a common connector:
•  Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to power supply.
•  Repair or replace the malfunctioning part.
If there is no common connector:
•  Repair or replace the wiring harness which has a short to power supply.
Go to Step 7.
6
INSPECT AMBIENT TEMPERATURE SENSOR CIRCUIT FOR OPEN CIRCUIT
•  Verify that the ambient temperature sensor and PCM connectors are disconnected.
•  Switch the ignition off.
•  Inspect for continuity between the following terminals (wiring harness-side):
―  Ambient temperature sensor terminal A—PCM terminal 1AL
―  Ambient temperature sensor terminal B—PCM terminal 1AN
•  Is there continuity?
Yes
Go to the next step.
No
Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals:
•  Ambient temperature sensor terminal A—PCM terminal 1AL
•  Ambient temperature sensor terminal B—PCM terminal 1AN
If there is a common connector:
•  Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
•  Repair or replace the malfunctioning part.
If there is no common connector:
•  Repair or replace the wiring harness which has an open circuit.
Go to the next step.
7
VERIFY DTC TROUBLESHOOTING COMPLETED
•  Always reconnect all disconnected connectors.
•  Clear the DTC from the PCM memory using the M-MDS.
•  Perform the KOEO or KOER self test.
•  Is the same DTC present?
Yes
Repeat the inspection from Step 1.
•  If the malfunction recurs, replace the PCM.
Go to the next step.
No
Go to the next step.
8
VERIFY AFTER REPAIR PROCEDURE
•  Perform the “AFTER REPAIR PROCEDURE”.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [MZR 1.6].)
No
DTC troubleshooting completed.