Corolla T-Sport (2004) Warning Lights

[SLH]

Hi folks,

I had some issues with accelerator pedal sticking, which subsequently turned into warning lights (engine, VSC, TRC).

Official Toyota dealer stumped but found some error codes:

P0171 - System too lean bank 1
C1330 - Open circuit to right front speed sensor
C1541 - Speed signal abnormal 

Their proposed approach was (at a very high cost) to:

Replace OSF speed sensor
Replace throttle body and cable

A local garage found a rat infestation in the engine bay, cleared it out, cleaned up.

Throttle sticking resolved, but after several days with my car they've given up and said wiring all looks good, they did notice that when the abs pump was disconnected one of the warning lights went out, but the error codes don't correspond at all.

I cannot really afford to pay Toyota nearly £3k when they can't guarantee a fix, I also can't really afford to replace the car at the moment, ideally need another couple of years out of it.

I would welcome any suggestions on where to turn next!

 

Thanks,

Rob.

[DerekHa]

Hi Rob,

Sorry to hear about your problems with your Corolla.

Are you ok with some simple DIY with the spanners or are you reliant on a garage for sorting stuff for you?

 

[SLH]

Mostly reliant on garages Derek.

[DerekHa]

43 minutes ago, SLH said:

Mostly reliant on garages Derek.

Best to ask around and find a trusted local mechanic, even in London there must be some local to you! Main Dealers aren't called Stealers for nothing, £3k is a huge amount of money on an older car a good garage would be lots cheaper than that. If whoever you've been to has thrown in the towel already they're likely not that good, knowledgable or reliable.

I think there's a good chance the C1330 code you have and the C1541 are related. If the right hand ABS sensor is open ciruit (C1330) that could also cause a C1541 code which relates to the power steering vehicle speed sensor which is also relies on the right hand ABS sensor to confirm the speed of your car for the power steering system. You could have a broken/damaged cable or connection (possibley rodent damage) or the ABS sensor connections are loose.

Your P0171 code can be a dirty Airflow sensor or an air leak the other side of the airfilter. There can be other causes as well. Even if your not that mechanically mindy there are a lot of Howto's on Youtube to give you an idea it's just a case of searching for the right codes and your vehicle model/engine.

Here's a Youtube video on the P0171 that might be of some use:-

 

 

 

[oldcodger]

Just to follow on from Dereks good advice.  its not that diffiucult to check the front abs sensor,  you need to partially remove the wheel arch liner which reveals the abs sensor connector way up under the wing metal work. where you can do a simple resistiance check with any little multimeter as detailed below.

A new sensor is typically £25+, the hard part is likely to be getting the corroded bolt out of the sensor, so plenty of penetrating oil first as the bolt heads can shear off !

 

[SLH]

Thanks both - I'll have a think and either have a go myself or go to a mechanic with a more specific brief thanks to you both.

[SLH]

Bit of an update @oldcodger @DerekHa

Taken the car to a third garage and they had it for a week, communication was not great throughout.

They said the car has "loads of error codes coming up, we can't find any problems, if you start replacing everything you may spend a fortune and never actually solve it".

Originally they had said they'd have a specialist come out to look at ECU and electrical system, but then said "who said that", and "oh you can go see them yourself", and then completely forgot to charge me amongst some vague grunting and shoulder shrugging...

Thoughts on this being ECU (which in my model I think is combined with the ABS pump, and second mechanic said error codes went away if you unplugged the ABS pump) and if so, any recommendations on finding mechanics that can actually diagnose / repair / replace?

[DerekHa]

Hi again Rob.

Sorry to here you're still struggling with this. Only good thing I see above is that your third garage forgot to charge you for what ever they had done if anything, then again it seems they did little anyway.

Only thing I can suggest in your situation is perhaps ask around amongst your nieghbours, that's if any still run cars in London and see if any can recommend someone. If you where in Birmingham, Coventry or Leamington Spa I could point you in the direction of mechanics who know what they're doing and it shouldn't be costing you 3 grand to get sorted either.

Or have a go yourself at that P0170 code and give that airflow sensor a clean like in that Youtube video. If you could DIY that one your a step closer to being sorted.

Keep us posted

[DerekHa]

Just had another read of your last post Rob.

I'm no expert unlike some very knowledgable people on the forum but I think it's unlikely your vehicle has a combined ECU/ABS unit. Uneven going back 20yrs most new cars were using an ECU along with a seperate ABS pump. The ABS pump will have an electronic control unit combined with it which monitors the ABS sensors for skidding and then they do thing to reduce the wheels locking up on you and give you more chance of stopping safely. ABS units have become a lot more advanced and are used to monitor lots of other factors associated with the rotation of the wheels,  stability and traction control amongst them.

Best to start with the more basic things and work through them or get a good mechanic who should be able to do that for you.

[SLH]

@DerekHa 

Thanks for the thoughts.

Finding a good mechanic seems easier said than done, though perhaps that's me getting jaded by three of them charging (or failing to) for diagnostics, holding onto the car for days, then giving it back and shrugging their shoulders.

[oldcodger]

Ditto   -

For the ABS/speed sensor problem, our action would be to check the connection to the OS speed sensor as the rats might easily have gone under the wing.  Think on your model,  if like ours, ithe ABS sensor  also acts as the road speed sensor, unless you have a  separate road speed sensor on the top of the gearbox ?

Easy enough to do with just the basic tools and a jack, along with a Support /Axle Stand !

Remove the road wheel and look at the actual base of the ABS sensor as  the finger in the pics shows, is the cable intact ?

Following the cable it goes up behind the wheel arch liner,  which needs to be partially removed, a 10mm spanner and a couple of screwdrivers to pop the clips out.

If you can ease part of it out so you have a clear view up towards the top of the strut spring you will, with a torch see where the abs cable joins the main wiring loom via a 2 pin connector.   Does the wiring look intact, not chewed etc ?

If all looks good, then dislodge the connector and disconnet the plug and socket and as in that earlier diagram check the resistance of the sensor with a simple test meter.

If the sensor is Open ciruit or shorted then it needs replacing, but that single bolt that hold the sensor in   needs to be heavily soaked in penetrating fluild overnight as its likely the thread is  rusted in and very difficult to remove, ours snapped off and had to be drilled out and retapped!

 

[DerekHa]

1 hour ago, SLH said:

@DerekHa 

Thanks for the thoughts.

Finding a good mechanic seems easier said than done, though perhaps that's me getting jaded by three of them charging (or failing to) for diagnostics, holding onto the car for days, then giving it back and shrugging their shoulders.

I've always been a tinkerer even from an early age, I learnt a lot of the basic car mechanics from my dad though he wouid use a garage for anything more than basic servicing. I couldn't afford garage fees so got more adventurous with taking stuff on with help and guidance from others.

Then way back in the the 90's when computers were just becoming the thing we got one and relied on someone else for keeping it working. Got tired of having to wait on them and started doing my own basic cleanups etc. Then got let down by a local computer shop with something more involved they couldn't fix but still charged for. Decided I'd have a look insid the case and solved the issue myself. Ended up building my own computers and upgrading them after that and still do.

It can pay to pick up a screwdriver and a spanner and have a go yourself, especially now as there are forums like this along with YOUTUBE that can all help guide you through. What Oldcodger has suggested is pretty basic stuff really.

[oldcodger]

28 minutes ago, DerekHa said:

I've always been a tinkerer even from an early age, I learnt a lot of the basic car mechanics from my dad though he wouid use a garage for anything more than basic servicing. I couldn't afford garage fees so got more adventurous with taking stuff on with help and guidance from others.

Then way back in the the 90's when computers were just becoming the thing we got one and relied on someone else for keeping it working. Got tired of having to wait on them and started doing my own basic cleanups etc. Then got let down by a local computer shop with something more involved they couldn't fix but still charged for. Decided I'd have a look insid the case and solved the issue myself. Ended up building my own computers and upgrading them after that and still do.

It can pay to pick up a screwdriver and a spanner and have a go yourself, especially now as there are forums like this along with YOUTUBE that can all help guide you through. What Oldcodger has suggested is pretty basic stuff really.

Nothing like the school of diy cars and computers etc, saved us a small fortune over the years, though not everyones cup of tea.

[Red_Corolla]

Just to add, please keep in mind that in order to diagnose and fix the wheel speed sensor, the whole circuit all the way back to the ABS computer needs to be considered, not just the sensor itself and the plug under the wheelarch, especially when there's a history of rodent infestation.

I would suggest having it looked at by a competent auto electrician, perhaps the sort of person who works mobile and/or specialises in diagnostics.

[SLH]

Quick update - on the recommendation of a local garage that refused to take my money got put in touch with a good mobile mechanic who specialises in electrical issues and diagnostics.

1. Found that the air intake to the engine was loose and tightened it
2. Cleaned the air flow sensor as recommended by the community above
3. Checked the wheel speed sensors as recommended by the community above and found no issues

Warning lights are (currently) all off after a couple of medium drives.

The mechanic said if this doesn't work, he recommends trying the following one by one, in order:

• Replace the airflow sensor 
• Replace the oxygen sensor on the exhaust
• Have the vacuum pipes checked for any holes
• Have the fuel pump flow rate checked to see if that's causing lean issues
• Only then, look at testing the entire wiring loom from ABS to ECU

He took 30 mins to explain everything in detail and why he thought each of those might be worth looking at.

The difference in service compared to the garages, being treated like a human being, actually getting a detailed thought process and not just some demented grunts...

Thanks for all the advice on the forums so far, my fingers are crossed it was just a dodgy air flow sensor and lose intake and I can sail through the MOT in a month, really want to squeeze a couple more years out of the car.

[Cyker]

This is the difference between a generic fitter garage and a trained and experienced specialist!

Keep that guy's number!!!

(In fact post the name and number here, I might need him one day!!  )