DTC P0131

BHE010200100W15

DTC P0131

Front HO2S circuit low voltage

DETECTION CONDITION

• The PCM monitors the input voltage from the front HO2S and the front HO2S output current when the engine is running. If the input voltage is less than 1.8 V or the output current is less than -5 mA, the PCM determines that the front HO2S circuit voltage is low.

Diagnostic support note

• This is an intermittent monitor (HO2S).
• The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
• PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle.
• FREEZE FRAME DATA is available.
• The DTC is stored in the PCM memory.

POSSIBLE CAUSE

• Front HO2S malfunction
• Connector or terminal malfunction
• Open circuit in wiring harness between front HO2S terminal A and PCM terminal 2B
• Short to GND in wiring harness between front HO2S terminal A and PCM terminal 2B
• Open circuit in wiring harness between front HO2S terminal B and PCM terminal 2C
• Short to GND in wiring harness between front HO2S terminal B and PCM terminal 2C
• PCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1

VERIFY FREEZE FRAME DATA HAS BEEN RECORDED

• Has 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

INSPECT FRONT HO2S CONNECTOR FOR POOR CONNECTION

• Turn the ignition switch off.
• Disconnect the front HO2S connector.
• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
• Is there any malfunction?
Yes
Repair or replace the terminal, then go to Step 8.
No
Go to the next step.
4

INSPECT FRONT HO2S CIRCUIT FOR SHORT TO GND

• Turn the ignition switch off.
• Inspect for continuity between the following circuits:
– Front HO2S terminal A (wiring harness-side) and body GND
– Front HO2S terminal B (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.
No
Go to the next step.
5

INSPECT FRONT HO2S

• Inspect the front HO2S.
• Is there any malfunction?
Yes
Replace the front HO2S, then go to Step 8.
No
Go to the next step.
6

INSPECT PCM CONNECTOR FOR POOR CONNECTION

• Turn the ignition switch off.
• Disconnect the PCM connector.
• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
• Is there any malfunction?
Yes
Repair or replace the terminal, then go to Step 8.
No
Go to the next step.
7

INSPECT FRONT HO2S CIRCUIT FOR OPEN CIRCUIT

• Turn the ignition switch off.
• Inspect for continuity between the following circuits:
– Front HO2S terminal A (wiring harness-side) and PCM terminal 2B (wiring harness-side)
– Front HO2S terminal B (wiring harness-side) and PCM terminal 2C (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.
8

VERIFY TROUBLESHOOTING OF DTC P0131 COMPLETED

• Make sure to reconnect all disconnected connectors.
• Clear the DTC from the PCM memory using the WDS or equivalent.
• Perform the DRIVE MODE 1 and 3.
• Is the PENDING CODE same as the DTC present?
Yes
Replace the PCM, then go to the next step.
No
Go to the next step.
9

VERIFY AFTER REPAIR PROCEDURE

• Perform the "AFTER REPAIR PROCEDURE".
• Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE.)
No
DTC troubleshooting completed.