Engine light comes on when driving on motorway, goes off when the car is turned off and on again

[mickburkesnr]

This concerns my 1998 Toyota Corolla 1.3.

So before Christmas I was driving on the motorway to London when the Check Engine light came on. I was doing about 70mph, I didn't notice any drop in performance. I was in a hurry so I got to my destination and turned the engine off. Left it alone for 30 minutes and got back in the car and drove off. The Engine light didn't come on until I was about half an hour on the motorway. Again 70mph. I got home, turned it off and turned it straight back on. No Engine light.

Over the course of the Christmas there's a specific road that I use to get home. It's a dual carriageway that leads to a roundabout. There's always stop/start traffic leading to the roundabout, and after it the road is clear. I accelerated hard after the roundabout (it's national speed limit) and the light came on. Same as before I turned it off and on, the light goes off.

From reading around the internet, the Toyota I have doesn't have an OBDII connector. It uses the older Toyota specific one I think, and from what I gather I have to bridge some wires, turn the ignition on and look at the flashing light sequence to diagnose the issue. The problem I have is that when I turn the engine off the light goes off until I'm revving the car.

So, does anyone know what I can do to solve this issue, or what the likely issue is?

[oldcodger]

Hi,

Got to ask, how do you know your were doing 70, thought your speedo was duff, assmume you sorted it - what was it ?

First thing to do is look under the dashboard, drivers side and can you see a white socket like the pics shows ?

It could be the old dash flash type or may need a proper code reader.

Assuming its the flash  type, with the engine / ign  off, get a wire and connect pin 4 to pin 13.

If its the flash type, then the engine check light will start flashing out the error code/s

Typically first number is blinked/flashed  with 1/2 second   gaps, then a 1.5 sec gap begore the second number, same for the third if used

If more than one code stored , then there is a 2.5 sec gap before the next number flashes.

After the last code, a 4.5 second gap and the sequence starts again.

Just remove the wire to end the readings.

Then look up what error the code refers to.

 

 

 

[mickburkesnr]

It's still broken, went to many a scrap yard all over the West Midlands and they either didn't have it or insisted I was wrong, that the car doesn't have a speedocable. I've got a GPS speedometer app on the phone and touch wood it seems to be accurate. No speed camera's flashing, not outpacing cars in front when doing 30mph. I've one on order now though so hopefully next week I'll resolve it - I'll update that post when I do!

I don't have the white socket under the dash, the only one I have is the diagnostic one under the bonnet. I'll try this method tonight, I thought it'd just be wiped clean if I turned the engine off. We'll soon find out!

[oldcodger]

No, the codes will be saved as long as the Battery is connected, you can clear the codes by disconnecting the Battery for 10mins or so.

Can you do a pic of the socket, have some info on toyota sockets / codes as my old 98 avensis had sensor problems.

 

 

[mickburkesnr]

Right, managed to get round to this while waiting for 250,000+ files to upload to my works web server!

I got a paper clip and put it in to the diagnostic port. Mine is the old OBD1 connector. The engine light flashes 4 times, then 2 more times, then there's a long pause. From what I gather this is error code 42 - Vehicle Speed Sensor Signal. So it's when there's no speed notification to the ECU for 8 seconds when the engine speed is between 2,500 and 5,000. Trouble areas are:

• Vehicle speed sensor circuit
• Vehicle speed sensor
• ECU

As I've posted before, the speedometer has been broken while this problem has occured. There was me thinking it was the speedo cable!

I wouldn't like to think it's the ECU, as this is the only error code present and the car's been fine otherwise. This leaves the, I assume, cheaper issues of either the Vehicle Speed Sensor or Sensor Circuit.

Only problem now, where the hell are they?

EDIT: Aparently it's on the back of the gearbox. I'll consult the Haynes manual properly tonight, as well as visit my friendly dealership for a quote on the part.

[oldcodger]

Found this diagram from a 2004 model and know exactly where it back up lamp switch is, but a bit difficult to work out the exact location of the speed sensor, though might give you an idea.