Help with O2 sensors / MAF *Avensis T25 2.0vvti 2005*

[noclue]

Hi Everyone (long time member, first time poster 🙂 )

I have a 2005 T25 (pre facelift) 2.0 vvti auto.

I've had the following symptoms - MPG down, power down (so much so, that the auto box changes down upon almost any acceleration), fuel smell at idol is high, occasional EML. 

So I read the codes (below)

Clearly the Air/Fuel is broken. 

My question is: 

I'm planning the sequence of repairs. Do I..

1. Replace the MAF? (Previous cars have led me to believe the MAF is often the route of all problems )

2. Replace the O2 sensors one or two at a time - If so, what ones first? Top or bottom? Bank 1 S1&2 first?

3. Replace all 4 sensors?

4. Anything else?

 

Many thanks 🙂 

 

P0156
Raw code: 0156
ECU: 10
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 2, bank 2 - circuit malfunction
Toyota: Oxygen Sensor Bank 2 Sensor 2 Circuit Malfunction

============2==============

P0136
Raw code: 0136
ECU: 10
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 2, bank 1 - circuit malfunction
Toyota: Oxygen Sensor Bank 1 Sensor 2 Malfunction

============3==============

P0133
Raw code: 0133
ECU: 10
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 1, bank 1 - slow response
Toyota: Oxygen Sensor Bank 1 Sensor 1 Slow Response 

============4==============

P0156
Raw code: 0156
ECU: 10
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 2, bank 2 - circuit malfunction
Toyota: Oxygen Sensor Bank 2 Sensor 2 Circuit Malfunction 

============5==============

P0136
Raw code: 0136
ECU: 10
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 2, bank 1 - circuit malfunction
Toyota: Oxygen Sensor Bank 1 Sensor 2 Malfunction 

============6==============

P0133
Raw code: 0133
ECU: 10
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 1, bank 1 - slow response
Toyota: Oxygen Sensor Bank 1 Sensor 1 Slow Response

[TonyHSD]

Hi, does the car burn oil and how much? Have you checked the spark plugs condition recently, replaced? You may try to clean the all 4 O2 sensors, clean maf and throttle body, replace air filter and spark plugs if needed. Add some injector cleaner into the fuel and take the car on the motorway for at least 20-30 min drive at around 2500-3000rpm, watch the speed , no need to be fast , rpm and time are important. Check also all rubber vacuum hoses , may have vacuum leak somewhere. If difficult to access the lambda sensors you can try cleaning first with cataclean or similar O2 cleaner that adds to the fuel and again motorway drive is needed to rise temperature and burn the carbon buildup. These are cheaper solutions, if they doesn’t work then replace might be the option.

[noclue]

Quote

 

Thank you Tony. I admit, it seems odd for ALL the sensors to fail... points elsewhere.

Not using oil. No nasty smoke (just smells of fuel). Air filter is weeks old. 

I'll do a little more investigating this weekend.

£300 for the sensors hurts a little, but not as much as my hands will hurt trying to get to the bl00dy things!

[TonyHSD]

It seems like you have rich fuel mixture, that can be as a result of dirty or faulty sensors or the sensors fail as a result of something else on the system. Family member has the same issues recently, looking now at cleaning and eventually replace of lambda sensor as pretty much anything else is done to date. 👍 Good luck with yours and please update any changes. 

[doc_14]

Hi there.

Have you checked the O2 sensors fuse? The errors are a bit annoying. Maybe the sensors are old or can be dirt in the system.

Check the connections between the sensors and the ECU, can be a short circuit too.