Hey guys, been lurking here a while, but now I need some help.

I have an 85 SR5 pickup, 22RE 5-spd, and just recently, it has become stuck in diagnostic mode. The check engine light flashes out codes while it is running, or the engine is off, but in the run position. The connector doesn't have the jumper in it, and the the wires look fine visually. Short of tracing the wires to find a short, anyone know of any common areas to start looking.

While I was checking connections at the ECU, I noticed that some water got in it. Think this could contribute to it. I have since relocated the ECU, but has the damage already been done?

Is it bad to drive around in diagnostic mode? Is it in a closed loop mode, or open during diagnostics?

Any feedback is appreciated.

 

Turns out it is probably the ECU.

The ECU goes into diagnostic mode when T and E1 are shorted. I performed a continuity test on the harness at the ECU. There is no continuity between T and E1, however when I insert the jumper in the diagnostic connector under hood, there is continuity. Looks like the harness checks out, so it must be a problem with the ECU.