Action Taken
ECM turns on "Engine Control System Fault" light. ECM commands BCM to display "SERVICE SOON" message on DIC. ECM will use right oxygen sensor signal to control fuel delivery unless Code EO13, EO44 or EO45 is set. If any of these codes are set, closed loop operation will be disabled.
NOTE:
The following step numbers refer to circled numbers on diagnostic chart. See Fig 1
. For circuit identification, see Figure
.
- With key on and oxygen sensor disconnected, parameter ED34 should read 0.38-0.57 volts. Significantly higher or lower readings indicate a problem.
- The ECM compares voltage on circuit No. 412 the ground on circuit No. 413. It is essential that the oxygen sensor ground and ECM ground on pin "B6" are at the same voltage potential with the engine running.