DTC P0031:00 [MZ-CD 1.6]

id0102g8700400

DTC P0031:00

A/F sensor heater circuit low input
DETECTION CONDITION
•  If the input voltage to the A/F sensor heater drive terminal in the PCM is low for 5 s or more even though the A/F sensor is duty-controlled at 93 % or less by the PCM.
POSSIBLE CAUSE
•  A/F sensor connector or terminals malfunction
•  Open circuit or short to ground in wiring harness between A/F sensor terminal C and PCM terminal 205
•  A/F sensor heater malfunction
•  PCM connector or terminals malfunction
•  Short to ground in wiring harness between A/F sensor terminal D and PCM terminal 203
•  Open circuit in wiring harness between A/F sensor terminal D and PCM terminal 203
•  PCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION
1
VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
•   Has the FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2
VERIFY RELATED REPAIR INFORMATION AVAILABILITY
•  Verify related service repair information availability.
•  Is any related repair information available?
Yes
Perform repair or diagnosis according to the available repair information.
•   If the vehicle is not repaired, go to the next step.
No
Go to the next step.
3
VERIFY RELATED PENDING CODE AND/OR DTC
•  Switch the ignition to ON (engine off).
•  Perform the Pending Trouble Code Access Procedure and DTC Reading Procedure.
•  Is the other PENDING CODE/DTC also present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [MZ-CD 1.6].)
No
Go to the next step.
4
INSPECT A/F SENSOR CONNECTOR AND TERMINALS
•  Disconnect the A/F sensor connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, and corrosion).
•  Is there any malfunction?
Yes
Repair or replace the connector or terminals, then go to Step 10.
No
Go to the next step.
5
INSPECT A/F SENSOR HEATER CIRCUIT FOR OPEN CIRCUIT OR SHORT TO GROUND
•  A/F sensor connector is disconnected.
•  Switch the ignition to ON (engine off).
•  Measure the voltage at A/F sensor terminal C (wiring harness-side).
•  Is the voltage B+?
Yes
Go to the next step.
No
Repair or replace the connector or terminals, then go to Step 10.
6
INSPECT A/F SENSOR HEATER
•  Switch the ignition to off.
•  Inspect the A/F sensor heater.
•  Is there any malfunction?
Yes
Replace the A/F sensor, then go to Step 10.
(See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [MZ-CD 1.6].)
No
Go to the next step.
7
INSPECT PCM CONNECTOR AND TERMINALS
•  Disconnect the PCM connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, and corrosion).
•  Is there any malfunction?
Yes
Repair or replace the connector or terminals, then go to Step 10.
No
Go to the next step.
8
INSPECT A/F SENSOR HEATER CIRCUIT FOR SHORT TO GROUND
•  A/F sensor and PCM connectors are disconnected.
•  Inspect for continuity between A/F sensor terminal D (wiring harness-side) and body ground.
•  Is there continuity?
Yes
Repair or replace the wiring harness for a possible short to ground, then go to Step 10.
No
Go to the next step.
9
INSPECT A/F SENSOR HEATER CIRCUIT FOR OPEN CIRCUIT
•  A/F sensor and PCM connectors are disconnected.
•  Inspect for continuity between A/F sensor terminal D (wiring harness-side) and PCM terminal 203 (wiring harness-side).
•  Is there continuity?
Yes
Go to the next step.
No
Repair or replace the wiring harness for a possible open circuit, then go to the next step.
10
VERIFY THAT DTC P0031:00 TROUBLESHOOTING IS COMPLETED
•  Make sure to reconnect all disconnected connectors.
•  Clear the DTC from the PCM memory using the M-MDS.
•  Perform the KOEO self test.
•  Is the PENDING CODE for this 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.
11
VERIFY AFTER REPAIR PROCEDURE
•  Perform the after repair procedure.
•  Are any DTCs present?
Yes
Go to the applicable DTC troubleshooting.
(See DTC TABLE [MZ-CD 1.6].)
No
DTC troubleshooting completed.