O2 Sensor before or after the Catalyst

Hi all,

I have a 1997 Toyota Corolla, my Engine Check light is on and the ODBII gave the following diagnostic report:

Scan Data:

MIL Status ON DTC Count O2 Readiness Complete Y Freeze Data Exists Y

Operational Data:

Readiness Monitors Complete Yes 01 Fuel System 1 Open Loop 02 Fuel System 2 Not Supported 03 Load Value 27.8% & 27.4% 04

Freeze Frame Data:

P0133 O2 Sensor Circuit Slow Response (Bank 1 Sensor 1) Fuel System 1 Closed Loop 01 Fuel System 2 Not Supported 02 Load Value 28.2 % 03 Coolant Temp 185 F 04

Trouble Codes: 1.- Trouble Codes P0130 O2 Sensor Circuit Malfunction (Bank 1 Sensor 1) P0130 O2 Sensor Circuit Slow Response (Bank 1 Sensor 1) 2.- Pending Codes No Trouble Codes Found

O2 Sensor Tests: 1.- O2 Sensor 1 Low Volt Switch Time 0.400v 01 High Volt Switch Time 0.550v 02 Min Sensor Volt 1.275v 03 Max Sensor Volt 0.000v 04 2.- O2 Sensor 2 Min Sensor Volt 1.275v 01 Max Sensor Volt 0.000v 02

Can anybody tell me which Oxygen sensor (before or after the catalyst) is having a problem?

Thank you, Vance

Reply to
vwu
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According to the trouble codes, it is the circuit for the O2 sensor before the catalyst.

Reply to
Ray O

Ray,

Thank you for your response, do you mean the following trouble codes:

1.- Trouble Codes P0130 O2 Sensor Circuit Malfunction (Bank 1 Sensor 1) P0130 O2 Sensor Circuit Slow Response (Bank 1 Sensor 1)

Is the O2 sensor located before the catalyst, how do I interpret the above trouble code is the one before the catalyst, not the one after the catalyst?

Thank you, Vance

Reply to
vwu

Here:

Circuit Malfunction (Bank 1 Sensor 1)

Reply to
hachiroku

I have a 97 Avalon and the bank 1 sensor 1 on my car was located after the Cat Conv.

Reply to
Da Ghost

Bank 1 refers to the cylinder bank that contains cylinder #1 - in the case of a 4 cylinder engine, there is no bank 2.

Sensor 1 refers to the sensor that is closest to the engine.

Reply to
Ray O

I also have a 97 Avalon and according to the Factory Service Manual, Page EG

259 (PO130), Sensor 1 refers to the sensor closest to the engine.
Reply to
Ray O

Thanks to all input's and now I know for sure to order the right O2 sensor.

Thanks aga> > Thank you for your response, do you mean the following trouble codes: > >

Reply to
vwu

Told Ya So...

Reply to
hachiroku

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