DTC P0140:00 [MZR 1.6]

id0102h3702700

DTC P0140:00

HO2S circuit no activity detected
DETECTION CONDITION
•  The PCM monitors the input voltage from the HO2S when the following conditions are met. Under the following monitoring conditions, if the input voltage from the HO2S does not even exceed 0.7 V though the short term fuel trim is controlled up to 20.5% for 9.6 s, the PCM determines that HO2S circuit is not activated.
MONITORING CONDITIONS
―  Drive Mode 03 (A/F sensor heater, HO2S heater, A/F sensor, HO2S and TWC Repair Verification Drive Mode)
―  Following conditions are met for above 20.8 s:
•  Engine speed: above 1,500 rpm
•  Engine coolant temperature: above 70 °C {158 °F}
•  HO2S voltage: above 0.1 V
Diagnostic support note
•  This is an intermittent monitor (A/F sensor, HO2S).
•  The check engine light 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 (Mode 2)/Snapshot data is available.
•  DTC is stored in the PCM memory.
POSSIBLE CAUSE
•  HO2S looseness
•  Leakage exhaust system
•  HO2S connector or terminals malfunction
•  HO2S heater malfunction
•  PCM connector or terminals malfunction
•  Short to ground in wiring harness between HO2S terminal A and PCM terminal 1AB
•  Open circuit in wiring harness between HO2S terminal A and PCM terminal 1AB
•  Engine internal malfunction
―  Engine coolant leakage to combustion chamber
―  Insufficient engine compression
•  HO2S deterioration
•  PCM malfunction

Diagnostic Procedure

STEP

INSPECTION

ACTION
1
VERIFY FREEZE FRAME DATA (MODE 2)/SNAPSHOT DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED
•  Have the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS (A/F sensor, HO2S related) been recorded?
Yes
Go to the next step.
No
Record the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS on repair order, then go to the next step.
2
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.
3
VERIFY RELATED PENDING CODE AND STORED DTC
Note
•  If the fuel monitor DTC, DTC P0132:00 is retrieved, ignore it until P0140:00 is fixed.
•  Switch the ignition off, then ON (engine off).
•  Verify the related PENDING CODE and stored DTCs using the M-MDS.
•  Are any other DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [MZR 1.6].)
No
Go to the next step.
4
INSPECT INSTALLATION OF HO2S
•  Inspect if the HO2S is loosely installed.
•  Is the HO2S installed securely?
Yes
Go to the next step.
No
Retighten the HO2S, then go to Step 14.
(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [MZR 1.6].)
5
INSPECT GAS LEAKAGE FROM EXHAUST SYSTEM
•  Visually inspect if there is any gas leakage between the exhaust manifold and HO2S.
•  Is there any leakage?
Yes
Repair or replace the malfunctioning part according to the inspection results, then go to Step 14.
No
Go to the next step.
6
INSPECT HO2S CONNECTOR CONDITION
•  Switch the ignition off.
•  Disconnect the HO2S connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is there any malfunction?
Yes
Repair or replace the connector or terminals, then go to Step 14.
No
Go to the next step.
7
INSPECT HO2S HEATER
•  Inspect the HO2S heater.
•  Is there any malfunction?
Yes
Replace the HO2S, then go to Step 14.
(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [MZR 1.6].)
No
Go to the next step.
8
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 or terminals, then go to Step 14.
No
Go to the next step.
9
INSPECT HO2S SIGNAL CIRCUIT FOR SHORT TO GROUND
•  Verify that the HO2S and PCM connectors are disconnected.
•  Inspect for continuity between HO2S terminal A (wiring harness-side) and body ground.
•  Is there continuity?
Yes
Refer to the wiring diagram and verify whether or not there is a common connector between HO2S terminal A and PCM terminal 1AB.
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 ground.
•  Repair or replace the malfunctioning part.
If there is no common connector:
•  Repair or replace the wiring harness which has a short to ground.
Go to Step 14.
No
Go to the next step.
10
INSPECT HO2S SIGNAL CIRCUIT FOR OPEN CIRCUIT
•  Verify that the HO2S and PCM connectors are disconnected.
•  Inspect for continuity between HO2S terminal A (wiring harness-side) and PCM terminal 1AB (wiring harness-side).
•  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 HO2S terminal A and PCM terminal 1AB.
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 Step 14.
11
INSPECT SEALING OF ENGINE COOLANT PASSAGE
•  Perform the “ENGINE COOLANT LEAKAGE INSPECTION”.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results, then go to Step 14.
No
Go to the next step.
12
INSPECT ENGINE COMPRESSION
•  Inspect the engine compression.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning parts according to the inspection results, then go to Step 14.
No
Go to the next step.
13
INSPECT HO2S
•  Reconnect all disconnected connectors.
•  Inspect the HO2S.
•  Is there any malfunction?
Yes
Replace the HO2S, then go to the next step.
(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [MZR 1.6].)
No
Go to the next step.
14
VERIFY DTC TROUBLESHOOTING COMPLETED
•  Always reconnect all disconnected connectors.
•  Clear the DTC from the PCM memory using the M-MDS.
•  Perform the Drive Mode 03 (A/F sensor heater, HO2S heater, A/F sensor, HO2S and TWC Repair Verification Drive Mode).
•  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.
15
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.