"Joe" <[email protected]> wrote in message
news:[email protected]
> These are the diagnostic codes I'm getting after my 92 4runner check
> engine light started up last night. Are there really 2 unrelated
> things that happened to go at precisely the same instant, or does this
> indicate a third, bigger problem? The vehicle is running fine. I'm
> worried that my ECU is causing all of this, and I'm not bright enough
> to do electrical diagnoses
>
> 21=
> OXYGEN SENSOR SIGNAL/OXYGEN SENSOR HEATER SIGNAL
>
> OPEN OR SHORT IN OXYGEN SENSOR OR OXYGEN SENSOR SIGNAL
>
> 43=
> STARTER SIGNAL--NO "STA" SIGNAL TO ECU UNTIL ENGINE SPEED EXCEEDS
> 800RPM
>
> --IGNITION SWITCH/CIRCUIT
>
> --ECU
>
I don't think the two codes are related unless someone or something has
disturbed a wiring harness between those components and the ECU. ECU
failures are very rare. Since you happen to have a short or open in 2
different components, I'd check the O2 sensor before replacing it.
--
Ray O
correct the return address punctuation to reply
news:[email protected]
> These are the diagnostic codes I'm getting after my 92 4runner check
> engine light started up last night. Are there really 2 unrelated
> things that happened to go at precisely the same instant, or does this
> indicate a third, bigger problem? The vehicle is running fine. I'm
> worried that my ECU is causing all of this, and I'm not bright enough
> to do electrical diagnoses
>
> 21=
> OXYGEN SENSOR SIGNAL/OXYGEN SENSOR HEATER SIGNAL
>
> OPEN OR SHORT IN OXYGEN SENSOR OR OXYGEN SENSOR SIGNAL
>
> 43=
> STARTER SIGNAL--NO "STA" SIGNAL TO ECU UNTIL ENGINE SPEED EXCEEDS
> 800RPM
>
> --IGNITION SWITCH/CIRCUIT
>
> --ECU
>
I don't think the two codes are related unless someone or something has
disturbed a wiring harness between those components and the ECU. ECU
failures are very rare. Since you happen to have a short or open in 2
different components, I'd check the O2 sensor before replacing it.
--
Ray O
correct the return address punctuation to reply
