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 DTC P0140 [L8, LF, L3]

DTC P0140 [L8, LF, L3]

id0102a1805300

DTC P0140

HO2S 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 0.55 V though the short term fuel trim is controlled up to 20.5 % for 9.6 s, the PCM determines that sensor circuit is not activated.
MONITORING CONDITIONS
- 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 is above 1,500 rpm.
• Engine coolant temperature is above 70 °C {158 °F}.
Diagnostic support note
• This is an intermittent monitor (A/F sensor , HO2S).
• 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 first drive cycle.
• FREEZE FRAME DATA is available.
• Are any DTCs is stored in the PCM memory.

POSSIBLE CAUSE

• HO2S deterioration
• HO2S heater malfunction
• Leakage exhaust system
• Open circuit or short to ground in wiring harness between HO2S terminal A and PCM terminal 2Q
• Insufficient compression
• Engine malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1
VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAS BEEN RECORDED
• Has FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record the FREEZE FRAME on the repair order, then go to the next step.
2
VERIFY RELATED REPAIR 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 AND STORED DTC
Note
• If fuel monitor DTC, DTC P0132 is retrieved, ignore it until P0140 is fixed.
• Turn the ignition switch off, then to the ON position. (Engine off)
• Verify pending and stored DTCs using the WDS or equivalent.
• Are other DTCs present?
Yes
Go to the appropriate DTC troubleshooting procedures.
No
Go to the next step.
4
IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA
• Is the DTC P0140 on FREEZE FRAME DATA?
Yes
Go to the next step.
No
Go to troubleshooting procedures for DTC on FREEZE FRAME DATA.
5
VERIFY CURRENT INPUT SIGNAL STATUS
• Warm up the engine.
• Access O2S12 for P0140 PID using the WDS or equivalent.
• Verify PID while racing the engine at least 10 times in PARK (ATX) or NEUTRAL (MTX).
• Is PID reading normal?

- More than 0.55 V at least once during engine racing

Yes
Go to Step 8.
No
Go to the next step.
6
INSPECT INSTALLATION OF HO2S
• Check if HO2S is loosely installed.
• Is sensor installed securely?
Yes
Go to the next step.
No
Install sensor securely, then go to Step 10.
7
INSPECT GAS LEAKAGE FROM EXHAUST SYSTEM
• Visually check if any gas leakage is found between exhaust pipe and HO2S.
• Is there gas leakage?
Yes
Repair or replace any malfunctioning exhaust part, then go to Step 10.
No
• Inspect the following wiring harnesses for open or short to ground circuit, repair or replace wiring harness if necessary.
- HO2S terminal A (wiring harness-side) to PCM terminal 2Q (wiring harness-side)
• Repair or replace wiring harness if necessary.
• If all items above are normal, replace malfunctioning sensor.
Then go to Step 10.
8
INSPECT SEALING OF ENGINE COOLANT PASSAGE
• Perform ENGINE COOLANT LEAKAGE INSPECTION.
•  Is the cooling system hold pressure normal?
Yes
Repair or replace malfunctioning part according to inspection result.
Then go to Step 10.
No
Go to the next step.
9
INSPECT ENGINE COMPRESSION
• Inspect engine compression.
• Is it normal?
Yes
Go to the next step.
No
Perform the engine overhaul for repairs, then go to the next step.
10
VERIFY TROUBLESHOOTING OF DTC P0140 COMPLETED
• Make sure to reconnect all disconnected connectors.
• Turn the ignition switch to the ON position. (Engine off)
• Clear the DTC from the memory using the WDS or equivalent.
• Perform the KOER self-test.
• Is the DTC P0140 present?
Yes
Replace the PCM, then go to the next step.
No
Go to the next step.
11
VERIFY AFTER REPAIR PROCEDURE
• Perform the "AFTER REPAIR PROCEDURE".
• Are any DTC present?
Yes
Go to the applicable DTC troubleshooting.
No
Troubleshooting completed.