1992 Cadillac Allante Service Engine Soon light

1992 CADILLAC ALLANTE
65,000 MILES
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KIWIGRAM
  • MEMBER
  • 2 POSTS
At key on, the SES light should light.

My light will com on at key on, but immediately turns off. The circuit is simple. From ignition switch to a 10 amp fuse, to SES light, to PCM to ground. I have replaced the PCM and instrument panel. No change.
Oct 27, 2013 at 3:05 PM
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HMAC300
  • CERTIFIED EXPERT
  • 48,601 POSTS
once it starts it should do that it normally only turns on if something is wrong.
Oct 27, 2013 at 4:05 PM
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KIWIGRAM
  • MEMBER
  • 2 POSTS
No. At key on, the light should remain on and stay on through engine start. When engine starts, the SES should extinguish. Currently, at initial key on, the light turns on but IMMEDIATELY goes off.
Oct 27, 2013 at 6:40 PM
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HMAC300
  • CERTIFIED EXPERT
  • 48,601 POSTS
then it's going to have to be checked for a shorted wire or a bad dash as they are digital and cause problems like you are experieincing
Oct 28, 2013 at 7:21 AM