Poor Mpg

[jako999]

Hi I'm new to this site so HELLO for the first time. My wife has owned a Rav4 VX auto on a 52 plate (42000 miles) now for 2 years 90% of the time is around town and she gets around 18-19 mpg I asked Toyota about this and they said it was fine we get around 24 on the mototway at around 75-80. The fuel seams to be getting worse and I now think its more like 15-16mpg around town so I had a small sevice done (not by Toyota) oil and air filter were changed, but its no better.

Would I be correct in saying a sensor failure would show up on the engine light on the dash, it also passed its emissions on the Mot. It drives well although I have to say it does feel like its holding back somtimes, but no missfire. I did think about the plugs but there not due for another 18000 miles and there not cheap.

Sorry to be a pain but has anyone got any ideas and can I read the ECU codes my self in any way as I have a Mazda MX5 and you car read the codes on that with a LED and a paper clip.

Thanks for your help.

[anchorman]

Hi jako, welcome to the club.

What you are saying doesn't surprise me that much, A 2.0 litre petrol driving a ton and a half of permanent 4WD with an auto box has a heck of a lot of work to do. For other markets they fit a 2.4 and I think that it is one of those cases where in practice the bigger engine might turn out better fuel consumption as it doesn't have to be worked so hard.

I,m off to work now and if somebody hasn't done so by the time I get home I will tell you how to extract the codes by your paper clip method. Whether there is anything stored would depend on the nature of the fault but my feeling is that anything bad enough to cause excessive fuel consumption would have put it on.

The recent spell of cold weather will have your engine running rich for significantly longer when the engine is warming up and the ever rising price of fuel will make you notice it more.

Regards

[anchorman]

Hi jako

As promised here is the method for using the engine fault light to read DTCs (diagnostic trouble codes).

Get ready! Have a pen and paper ready to note the codes.

The diagnostic plug is just up behind the bonnet pull. If you look at it you will see 2 rows of 8 terminals. The top row is numbered 1 - 8 and the bottom row is numbered 9 - 16.

Switch the ignition on. Use your paper clip or similar test wire to connect terminals 13 and 4. It might help you to mark these with a felt pen before starting. Do not connect any other terminals as a mistake could cause some damage to the ECU or other components.

The engine fault light will begin to flash out the code after 4.5 seconds. The codes are flashed to represent a 2 digit number. Each flash is 0.5 seconds long and each space is 0.5 seconds long. A space of 1.5 seconds will occur between the first and second number.

Example;

Code 12 (represented by dashes and asterisks here)

START*********-***-*-

Each dash (flash) is 0.5 secs and each asterisk (space between flashes) is 0.5 secs

Code 31

START*********-*-*-***-

There may be more than one code stored in the memory in which case the will be displayed with the lowest number starting first. There will be a 2.5 second space between the first and second code, e.g.

Codes 12 and 31;

START*********-***-*-*****-*-*-***-

If you leave it connected, after 4.5 seconds the codes will be repeated and so on.

To finish testing remove the connector the turn off the ignition - not the other way around. Note that disconnecting the Battery at any time will erase stored codes.

There are quite a few codes and I haven't got time to list them all now. The best thing is to read them (if they exist) and let us know and I or somebody else will tell you what they are.

Good luck

[jako999]

Thanks for that I will have a go but at work for the next four days so will have to be after that.

Thanks again

[bothwell_buyer]

Which petrol are you using?