Hi Guys

I've got a 91 LS400 that is throwing a code but I cannot read it because the Check Engine light doesn't work. I noticed the TRAC light was coming on and I know that a Check Engine light automatically sets TRAC.

I read the TRAC codes and got 51 - Problem in engine control system .

It was only at this point that I realised the Check Engine light never come on. Not in "Key-ON" and nothing when trying to check for codes either. I can only assume that its either broken or somehow disabled?

Main issue is that I can't read the codes to find out what the error is. It would be nice to restore the function of the check engine light but not really needed.

Any help with this one??

 

sounds like the ECU is dead/dying.....though you could try to replace the bulb in the cluster first to rule that out.

 

Car drives just fine with no apparent symptoms. Traction indeed works when the light is out as does ABS.

I know I can't rule out a faulty ECU but at this point I really think its probably just the light thats not fuctioning.

The Trac (and I guess Engine Light should have as well) only came on around 35mins into my last drive. I had reset the ECU when I had to remove the battery just previous to that.

 

bulb was indeed faulty. Now I just have to wait for the error to reapear as I cleared it when I took the battery off to work on the dash.

 

Are the MIL bulb flashes actually used to read codes in OBD I? Seems like I read that somewhere awhile back. Aren't most OBD II readers backwards compatible to read OBD I codes? I only have OBD II and CAN vehicles, so the bulb doesn't matter much, except to alert you; it's the code reader that provides all the info, of course. I love how the new readers and scan tools can trap and graph real time info, as well as ABS codes, for little cost. Ain't technology great!

Steve