Rav 4 Warning Lights - Help Please

[pjmurf]

Hi,

new member here and desperately looking for some help (is that cheeky?). We have a 2004 Rav4 XT4 VVTi with warning lights. Our engine management light and the VSC/Trac lights are on and weve had it in to 4 (yes four!) garages now without success. The code reads that its something to do with the timing chain so we were advised to get it changed which we did without success. We then put it back into the same garage to get it all checked and it all seems ok. Weve also had the actuator cam changed and all the wiring checked still without success. All 4 garages log the same faults timing chain but as I said it has been well checked with no faults found. Through this whole experience that has lasted about 2 years now the car has ran perfectly. It drives just as well now as it did before we had the chain done so the performance has never been an issue. TO be honest we have run out of ideas now so any advice would be greatly appreciated.

Thanks and sorry to start off on the forum with an issue.

[gjnorthall]

What code or codes are being stored? Presumably you've erased the stored code - how quickly does the engine light illuminate again? Sometimes timing chains stretch and timing becomes erratic resulting in fault codes on the cam / crankshaft position sensors - what exactly was changed when the chain was replaced? How many miles has the car covered up to the fault appearing and has the car been serviced regularly?

[pjmurf]

Thanks for replying gjnorthall.

Sorry for the delay I wanted to make sure that I had all the right info.

The codes and description are :-

P0012 Camshaft Position ‘A’ – Timing over – Retarded (Bank 1)

P0012 Camshaft History Position ‘A’ – Timing over – Retarded (Bank 1)

Obviously the same but I thought that I'd better add them both just in case.

The time for the lights to come back on varies but no longer than 2 hours (usually about 30mins)

Items that were changed were:- Chain Damper, Slipper - T/Chain, Chain Tensioner, Gear assy cam, Cam gear, timing chain, & water pump.

The car had done about 65k when the problem developed (we bought it with just under 54K on the clock)

And no the car wasn't serviced regularly before we bought it but we got it serviced at about 55K.

[gjnorthall]

I can't for the life of me understand why a garage would change all these parts due to a P0012 code! In any event, the timing chains etc on this engine aren't known to be problematic - particularly at the sort of mileage you quote. Wear is taken up by the tensioner and once the tensioner adjustment has been used up - the chain will sound like a bag of hammers - I take it that this wan't an issue on your car.

Basically on the VVTi engine - the angle of the inlet camshaft (valve timing) is varied by the ECM (Engine Control Module) in order to optimise torque, fuel efficiency etc etc. The ECM sends a signal to a solenoid which operates an oil control valve (OCV) which in turn operates the valve timing unit - it's done using the engine oil pressure. The ECM uses the signals from the cam and crankshaft sensors to determine the actual amount of advance / !Removed! on the inlet camshaft. It then compares this with the desired value as determined by the ECM. If the two values don't match then a fault code is flagged. P0012 means that the ECM is asking for the timing to advance but isn't detecting the advance (in other words, the valve timing is retarded compared to where it should be).

Often a genuine P0012 code will give symptoms such as rough running, poor fuel consumption etc etc and you indicate that this isn't the case on your car.

Unfortunately the fault can be due to a sensor or wiring issue or a fault with the solenoid / OCV / timing regulator. (the latter can result from low oil level, dirty oil etc). There have been issues on other Toyotas with the VVTi unit and there have been Technical Bulletins on the subject. In the absence of obvious faults, the first course of action is to prove (or otherwise) that the VVTi is functioning as it should when signalled. If it isn't, then it's a case of identifying which part of the system is faulty.

My immediate thought would be to let a Toyota garage to take a look (presumably the four garages you mention weren't Toyota) - this is quite a nutty problem and would be beyond the capability of many garages not familiar or not having technical detail of the Toyota VVTi system.

[pjmurf]

To be honest the first garge that I put it into was Toyota. Their actual words were 'requires modified timing chain, runners, tensioners, cam gears, crank gears and ECU. They quoted us £1400 to do everythngi exept the ECU as they wanted to charge us separately for that (somewhere around another £1000).

So we took the car somewhere else and they said a similar thing to Toyota hence the reason we went ahead with getting it done. Now I'm very reluctant to put it into Toyota again.

I sopke to someone that was trained at Toyota yesterday and he told me he thought that it was the control unit for the VVT, however he still said that he would need to remove the timing chain to replace the unit - again I'd be surprised if I get change from £1000 - hardly seems worth it for a car that in good condition is only worth £3500.......

[pjmurf]

Should have added that I've never been that happy with the fuel comsumption - around 25mpg around town - but I just put that down to the type of car. As for how at ran, that's never been a problem in fact we bought a 07 SAAB 93 a couple of years ago and the Rav has always ran far better than the SAAB.

[gjnorthall]

Sounds as if the garage attempted to solve the problem by replacing everything imaginable - a ridiculous state of affairs. It would be possible to home in on the fault with a proper diagnostic approach - the possible causes are well known. You're correct, that the solution may well be expensive, and if you intend keeping the car - I understand the logic of doing nothing and just living with the engine light illuminated. The MPG you quote is about what you'd expect around town.