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Robert, UK Qualified Car Technician
Category: Car
Satisfied Customers: 4571
Experience:  Fully qualified / self employed garage technician in the UK
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The TRC off and VSC lights have come on a couple of times in

Resolved Question:

The TRC off and VSC lights have come on a couple of times in the last fortnight, along with engine issue light. Took car that garage who reckoned it was a sensor issue. Reading other answers here, could it be being caused by either a leaky exhaust or worn brakes??
Submitted: 2 years ago.
Category: Car
Expert:  Robert replied 2 years ago.

Hi..there apologies for the you still require any help with this?

If so what faults codes did they say exactly was stored or what sensor even?

Customer: replied 2 years ago.
I think the previous time it was the sensors on the front wheels and they said both had come on which was unusual. It has had new tyres fitted to the front wheels about a week or two previously. I don't know what codes came up, sorry, just that these warning lights came on.
Expert:  Robert replied 2 years ago.


Ok..firstly it has to be sure thatthe correct tyres/pressures are on the front..considering the abs system which those system in regards ***** ***** lights run through by mointioring via the speed sensors on all wheels..any differance in rotaional speed picked up against the back axle might throw that off and bring those lights on..which "could" be the reason for them picking up on both front sensors at the same time maybe..which is indeed quite unusual to be honest unless there a fault in the abs control as precaution certainly ensure the tyres are correct and match all round aswell as pressures..have they tried clearing the codes and then retest..the check engine light could well be another fault altogether

on the engine really does require knowing what the actual faut codes are being logged before moving any further forward to be honest..if the garage isnt able to deal with it or has the equipment to do so then maybe another will if you want to try and avoid the dealer route if prefered...... As far a worn brakes goes..cant see it causing this type of fault - Leaking exhaust in a sense can cause the check engine light if the leak is causing problems with the o2 sensor"s" on the exhaust system either leaks before or after or the cat converter itself..but as it stands we really need to know exactly what the fault codes are to be able to investigate further rather than just replace parts on the off chance it will solve a good local garage with the correct diagnostic equipment and know how using the equipment should be able to trace this down..
Customer: replied 2 years ago.
With these lights on, is the car fundamentally safe to drive?
It isn't indicative of a failed shock absorber or something more serious, is it? The car "looks" OK and seems symmetrically balanced. It is possible that the fronts have been under inflated as the logbook recommends 35 for a mixture of medium to fast driving which seems quite high, and it may be that ATS set them rather lower. I'm seeing the garage tomorrow morning to get it looked at again and will ask them to quote the fault codes to me.
Expert:  Robert replied 2 years ago.

Hi..sorry for the delay..

In a sense its fine to drive as it stands..but not for any grreat distance to be suspension issues wouldnt likely cause say it either more a possible engine management related fault/abs control module or steering angle sensor..but like i say its hard to say for sure without proper diagnoses/fault codes....but yes certainly check the tyres out ensure they are the same size all round.looking at the tyres size on the side wall and ensure the pressures are correct all round best done on cold if you have one of these small electric tyre inflaters with a guage - that work off your 12v cig lighter socket then you can check them..

Customer: replied 2 years ago.
Sorry for delay, just a couple more details: the garage noted the following codes this morning when they reset
C1201 & P0380. The latter seems to relate to a lighting system fault which mystified us as there doesn't seem to be anything wrong with the lighting, the mechanic had a look at the brake pads and comfirmed they are worn, but not dangerously so.
I checked the type pressures yesterday, and they are all correctly inflated per the Toyota hNdbook recommended pressures.
Any further thoughts? The mechanic suggested that if the lights come on again to book the car in and they would take all four wheels off to have a really close inspection.
Expert:  Robert replied 2 years ago.


Lighting system? cant be... the codes you have givin are related to the ECM / Glow plug ,heater circuit malfunction...

C1201 - malfunction in the engine control system is detected - and thus the operations of VSC and TRC are prohibited hence those me that sounds like a communication fail possible in the wiring harness or unfortunatly the ecm itself is at fault.not cheap to repair!,HARNESS AND CONNECTOR (ECM - SKID CONTROL ECU) .they would have to check both areas the harness for issues..if the later ecm is at fault then there places online ,ecu/ecm repairs..bba reman and such like who maybe able to repair it or test it..but need to be sent off..

P0380 -Is a Glowplugs fault , heater circuit a malfunction. either the plugs themselves/wiring to control relay...they need to test the glowplugs in turn to see if one of them are faulty..

I feel from what your saying in regards ***** ***** to take all 4 wheels off to investigate doesnt sound like they are able to fully deal with the problem..they have the codes there but they are looking in all the wrong places..maybe might be time to seek someone else with a better understanding to deal with the problem..

Customer: replied 2 years ago.
What would be a typical cost if the ecm needs repair or replacement? Will a Toyota franchise charge me the earth to sort it out?
Expert:  Robert replied 2 years ago.


Best to actually visit or enquire with the site - depending on the nature of the issue if the ecm is at fault can vary widely on price..whether it be repaired or other wise... ....but as it stands it would seem you would require a better tech to trace the harness/main connectors on these harnesses for corrosion to the ecm or equipment - diagnostic tech to actually get any further forward..the dealer would likely be a last resort id say but it might well be your only avenue in regards ***** ***** like surfacing like you have..but the costing will likely be that somewhat higher...... Doing a bit of digging on that C code -- i note you mention the pads are indeed low..but on the odd occasion this could flag up this code ."so bear that in mind" due to the caliper pistons having to increase there travel due to the pads being worn,this in turn causing the brake fluid level to drop and thus could be brake fluid level warning switch sends the approp riate signal to the skid control worn they are yours? if nearing the metal backing then it could well be time for them to be replaced..

but do not top the fluid up as it is now with the pads worn..cause you'll end up having brake fluid spill out the reservior when they retract the pistons back to fit new pads in...but i wouldnt go down the route of condemming the ecm/abs yet..until those other areas have been checked out..
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