Engine Light on dashboard - help please :-(

There are a myriad of possible causes. I think your best of hope learning more is to ask around your friends to see if one owns an OBD2 code reader you can borrow.

Plugging that into the OBD2 port with the engine running when that symbol is showing on dash should let you get a code. Looking up that code on the Internet should tell you what the system things has one wrong, and may give you some ideas of what to do.

One common (and cheap to fix) problem that causes that light is an imperfectly seated gasoline tank cap. If the light is on now, run right out and try re-seating the cap.

 

If you can post a picture of the light it will be most helpful. That's very low milage for a 2004. I wonder if it was well maintained before you got it. I fear it may be a problem with the inverter and blocked cooling lines causing it to overheat. You will probably have to go to the dealer to get to the bottom of it.

 

[deleted for silly irrelevancy]

 

What is the powertrain warranty in the UK? In the US, the car would still be covered and hence I would suggest taking the car to the dealer.

I am assuming that your gallon is the Imperial gallon, so 57 mpg means ~47.5 miles/US gallon, which is good.

 

There was a Toyota technical note about water getting into the igniters (aka., the spark plugs.) I don't know all of the details but they had a fix for the problem. But to ask about a related problem, do you 'hear' water when driving or especially turning?

There is a problem with the drain holes getting plugged in the pan that holds the windshield wiper motor. This water, if it is there, could easily be part of the problem. I've not read of a fix other than to make sure the pan gets periodic maintenance to clean out the debris.

Bob Wilson

 

In the US the powertrain warranty is 5 years/60K miles.
Toyota Warranty and Coverage

You have correctly interpreted DTC P0301. Cylinder #1 is closest to the right-hand fender (or driver's side fender in UK). Bob offered a good suggestion about inspecting for water leaking from the cowl into the spark plug wells; a TSB exists to that effect.

If you wish to DIY, I suggest removing the spark igniter over the plug, then looking into the spark plug well to see if any moisture is within. Also examine the spark igniter to see if there are any cracks or discoloration of the plastic body; or corrosion of the low voltage terminals on top and the high voltage connector inside the plastic shell.

If you see no problems, then remove the spark plug for inspection. Correct spark gap is 1 to 1.1 mm. The gap of a used plug cannot be adjusted. The porcelain insulator at the tip should at worst have only a very light coating of combustion products on it and should have a near-white color. The spark plug porcelain tail should not have any cracks or burn marks.

If you need to replace the plug, only use the correct Denso or NGK iridium spark plug; your owner's manual should show the model #s.

Tightening torque of the spark plug is 13 ft.-lb. Tightening torque of the spark igniter bolt is 82 in.-lb. To improve your access to the spark igniters, it would help to first remove the relay box mounted to the cowl.

What is a "car fundi"??

 

:usa2:

http://priuschat.com/forums/toyota-prius-service-bulletins-tsbs/31384-list-tsbs-2004-dtcs.html

Service Bulletin Num : 06305 Date of Bulletin: DEC 16, 2005
NHTSA Item Number: 10018851
Component: ENGINE AND ENGINE COOLING:ENGINE
Summary:
M.I.L. ON DTC P0300, P0301, P0302, P0303, OR P0304. *TT
Make : TOYOTA Model : PRIUS Year : 2004
Manufacturer : TOYOTA MOTOR NORTH AMERICA, INC.

 

You might take a peek at Hobbit's essay and the photos at the end:

Prius heat-efficiency mods
​

In particular, check out the windshield wiper pan photo near the bottom.

Bob Wilson

 

I suggest that you look at the cowl panels located below the windshield wipers. Note the vertical seam between the two plastic panels. Was sealant applied to prevent water from dripping down onto the engine valve cover?

If not, you'll probably be paying another £245 next winter to replace spark igniter #1 again, after the next downpour when your car is outdoors.

 

If you're getting the light *flashing*, that indicates misfire
so severe you're risking engine damage. That's in the spec for
how the MIL is supposed to work. If it just comes on and stays
on and sets the code, that's not quite as critical but
obviously still needs attention.
.
_H*

 

As I recall there was a TSB for some '04s to correct the weather sealing around the engine compartment. Check to see whether yours needs this.