What do I do about the warning light on my Corolla?

Hi, I have a 2004 Toyota Corolla and the engine management light keeps coming on and then going off after a few days. It could be a week or more before it comes on again. I brought it to a mechanic and he said that it was a problem with the oil pressure release valve and he flushed out the system and replaced the oil, but the light still came on. He said that he was onto Toyota and it said it was not a major problem. What do you think?

Gemma Maguire (Dublin)

May 2012 Filed under: fault

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Expert answer

Hi Gemma,

First of all, we need you to confirm whether this is the engine management light or the oil pressure light you are referring to, as that's important! Those Corollas are known to have issues with gumming up the gauze that leads into the oil sump, which could lead to oil pressure problems - hence illuminating the oil pressure light. Likewise, it could be the pressure release valve as mentioned by your mechanic. If he flushed that out and replaced the oil and filter then the next step is actually to replace the oil light switch itself - as it may be faulty. If it's not, then the sump needs to come off and he needs to look at removing and cleaning the gauze.

However, if it really is the engine management light then you need the car hooked up to an OBD (On-Board Diagnostics) reader to extract the fault code and trace down the problem. This will only be possible when the light is on of course, which is tricky if it's an intermittent problem.

Come back to us if you need more assistance.

Shane O' Donoghue - Complete Car Adviser
@Shane_O_D