P0420 / P0171 / P0135 / P0125 Corolla T-Sport

[KennyKen1988]

Luckily this is now resolved but I thought I'd share my experiences after having my catalytic converter and O2 sensors stolen.

Complete exhaust centre section with cat replaced for third party standard equipment.

Febi bank 1 sensor 1 replaced

£25 eBay bank 1 sensor 2 replaced

Initial codes when running new parts:

P0420 - This was an exhaust leak at the manifold to exhaust connection.

A couple of months on suddenly PO171 - Resolved by removing  cleaning MAF.

Smoke tested intake via brake booster.

Two days later P0135 came up followed by PO125:

Checked O2 sensor wiring and heater circuit fuse all okay.

Fault log report generated by Torque for Android
=================================================

Vehicle VIN: Not present
Vehicle Manufacturer: Unknown
Vehicle Calibration ID: Not present

Current Fault Log
------------------
P0125: Insufficient Coolant Temperature for Closed Loop Fuel Control
P0135: O2 Sensor Heater Circuit (Bank 1 Sensor 1)

Pending Fault Log
------------------
ECU reports no pending faults

Historic Fault Log
------------------
ECU reports no historic faults
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------

End of report.

Mode $06 report generated by Torque for Android ================================================  Vehicle VIN: Not present Vehicle Manufacturer: Unknown Vehicle Calibration ID: Not present  Unit and scaling information are not supplied with the data from the ECU for this type of vehicle. Consulting the manufacturers service book for this information is recommended.  Test report: ------------------ TID:$04 CID:$01  - High sensor Voltage for switch time calculation Min: 3,276 Test result value: 1 FAIL ---- TID:$04 CID:$02  - High sensor Voltage for switch time calculation Min: 3,276 Test result value: 7,382 PASS ---- TID:$0a CID:$02  - Sensor period(calculated) Min: 0 Test result value: 255 PASS ---- TID:$0a CID:$03  - Sensor period(calculated) Min: 0 Test result value: 255 PASS ---- TID:$04 CID:$01  - High sensor Voltage for switch time calculation Min: 3,276 Test result value: 1 FAIL ---- TID:$04 CID:$02  - High sensor Voltage for switch time calculation Min: 3,276 Test result value: 7,382 PASS ---- TID:$0a CID:$02  - Sensor period(calculated) Min: 0 Test result value: 255 PASS ---- TID:$0a CID:$03  - Sensor period(calculated) Min: 0 Test result value: 255 PASS ----   End of report.

Checked waveform for the O2 sensors and bank 1 sensor 1 showed no activity whilst engine was running.

Turns out the O2 sensor had failed after four months. Replaced for a proper Denso DOX-0280 and all is now well.

I have posted this just to help others.

[APS]

Well done on the troubleshooting. Yet more evidence not to bother with cheaper O2 sensors. Thanks for sharing.

[KennyKen1988]

Absolutely APS. Surprisingly the febi sensor was not cheap but still a bit letdown.

I strongly advise Denso sensors only for Toyota.