SL L4-1.9L SOHC VIN 9 (1991)
With an SPI communication failure, technicians and some customers may comment on intermittent:
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Cooling fan operation or high coolant temperature
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A/C does not get cold
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Increased engine idle speed, in Park or Neutral
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No RPM signal or tachometer inoperative with vehicle running
An SPI failure causes all of the listed conditions to happen at the same time.
CAUSE:
An SPI communication failure occurs during an incorrect PCM power down that can be caused by repeated cycling of the ignition, calibration download,
battery connect or disconnect.
CORRECTIVE
ACTION:
Turn the ignition off, wait 10 seconds to reset the PCM and then start the vehicle.
NOTE:
If engine coolant temperature is 42~C (106~F) or above, it may take up to five minutes of ignition off time to reset the PCM.
If any of the vehicle symptoms of intermittent no fan operation or high coolant temperature, no A/C cool down, increased idle, or no RPM or tachometer
inoperative still exist, refer to the appropriate Saturn Service Manual section.
