CEL issue (1 Viewer)

[HuyFZJ80]

Picked up a 94 FZJ recently, and just found out that my CEL should light up when I go to start my engine. I took out the gauge cluster to check my bulbs, and they don’t appear to be blown (connections inside the bulbs look ok and not separated). Most of the other lights seem to come on, except my CDL, but that’s another problem for another thread. Does anyone know why your CEL won’t turn on, and where should I start my troubleshooting at? Thanks, already learning a ton on this site

 

[ppc]

@HuyFZJ80 ,

You need to check those bulbs with a meter. Are they incandesce bulbs? Does the vehicle start? With the key in the "ON" position before starting it should be on.

 

[voodu3]

Definitely check the bulbs like @ppc said. When my CEL stopped working I needed to replace the ECU. If the bulb is good then checking the ecu would be my next step. My CEL was intermittent before the ecu quit working.

 

[jonheld]

If the engine runs, then either the bulb is bad, the connection on the cluster to the bulb is faulty, or there is a faulty wire from the ECU to the cluster.
If the engine doesn't run, then we have to do some diagnostics.
Typically, no CEL with the key in the ON/RUN position before cranking the starter = no start.

 

[HuyFZJ80]

Bulbs are incandescent, and definitely work as I’ve swapped bulbs between known working bulbs and my CEL. Engine runs fine, so it must be some faulty wiring somewhere. Guess I’ll need to brush up on my multimeter skills. Thanks fellas!

 

[jonheld]

Bulbs are incandescent, and definitely work as I’ve swapped bulbs between known working bulbs and my CEL. Engine runs fine, so it must be some faulty wiring somewhere. Guess I’ll need to brush up on my multimeter skills. Thanks fellas!

The CEL lamp socket is fed +12 from the 10A GAUGE fuse and is illuminated with a logic low from the ECU connector E10 pin 4.
You can also monitor the ECU logic from the diagnostic connector on the firewall pin 2 (W). You should get a logic low with the key in the ON/RUN position.

All info is available in the FSM and EWD in the resources section.

 

[HuyFZJ80]

The CEL lamp socket is fed +12 from the 10A GAUGE fuse and is illuminated with a logic low from the ECU connector E10 pin 4.
You can also monitor the ECU logic from the diagnostic connector on the firewall pin 2 (W). You should get a logic low with the key in the ON/RUN position.

All info is available in the FSM and EWD in the resources section.

I appreciate this. It’ll give me somewhere definitive to look. To be honest, I’ll an absolute beginner when it comes to electrical, but it sounds like after this, I’ll be leveling up a bit

 

[HuyFZJ80]

Downloaded the FSM as well. Feels like I’m reading a foreign language when I’m looking at these electrical schematics. Time to get my reading glasses out and start studying

 

[landcrshr]

Even having years of experience, I found there was a learning curve with the scematics in the EWD. Reading the "How to use this manual" section in the beginning made it all come together.