engine diagnostics for levin

Hi
I have an AE101 Levin 4agze GTZ manual

It is intermitently going into limp mode

I want to run diagmostics to look for faults, but I cannot get this car in the Diag Mode.

I have shorted pins e1 and te1 in the diagnosis plug, then turned on the ignition........ no flashing CEL nothing


Am I doing something wrong?
Any help would be apreciated!!!

cheers
cue

have you checked to see if the bulb for CEL is working?

The CEL should still flash even if you have no error codes stored (a constant repeating flash is the code for "no error"), so I'm guessing it's either a problem with the bulb or the wiring from the dash to the ECU.

thanks for the replies guys, really appreciate it

The globe is fine as the car is in limp mode at the moment, so when driving the CEL is always on.

I checked the wiring from the Diag plug TE1 to the ECU and thats fine.
the E1 also earths as expected.

While I had the ECU out checking wiring I noticed 2 capacitors had leaked onto the board, so I replaced them today.
Once done after I had put the car back together no limp mode for about 10 minutes, but now its back again.
I am hoping putting the new caps in might fix the diagnostic issue, will try again a bit later to see if i can get it into diagnostic mode.

Leaky caps are a classic 90s Toyota ECU problem...

Out of curiousity, what fuel are you using? AE101 GZEs are extremely picky when it comes to RON.

yeah did some reading many 90's cars have these issues.

I tend to use 98, but every now and again i have put 95 in. could shitty fuel put me in limp mode?

Yes, AE101 GZEs are very sensitive to knock, especially around ~5000rpm. They were tuned for 100RON in Japan so anything less than 98 can very easily cause knock issues. Although from memory that doesn't put it in "limp mode", just retards the timing for a short period. Still, could be related.

Check all your sensors too (air temp. MAP, coolant temp etc)

ok tried to put the car in diag now that i have changed the dodgey looking caps in the ecu, still cant get in to diag

cant replace anymore capacitors as the electronics stores here in perth cant get the 10v units.

balls, im stuck!

So you're not getting the "no error" CEL flash at all?

Hiro that is correct
stort E1 and TE1 turn ignition on, no flashing of CEL whatsoever.

Have you tried any of the other diagnostic port jumpers? TE2 and E1 for test mode (same as diagnostics but for road-testing, CEL should still flash), +B and FP to prime the fuel system etc etc.

Check all the pin-outs on the diagnostics port too, one of them should be the CEL pin too so if the codes aren't coming out of there (make a test lamp with an LED) then it is probably an ECU or wiring issue.

Also, can't hurt (if you haven't done it already) to re-set the ECU to clear any codes or faults that may no longer exist - pull the EFI fuse for a minute or so to re-set everything whilst still keeping your radio presets (pulling the battery terminals off does the same thing but you lose radio memory etc)