Author Topic: 1981 Eldorado 368 8-6-4 code 18  (Read 228 times)

Offline Tonyv_73

  • Posts: 61
  • Name: Anthony Vanacore
1981 Eldorado 368 8-6-4 code 18
« on: June 13, 2017, 09:02:23 AM »
Just had a lot of work done on my 81 Eldorado Biarritz. (New radiator, plugs, wires, cap, oil change, new filters, pcv, exhaust, front axles, front shocks)  And now it's having a rough idle.  The computer is showing a code 18 which means an "open crank signal circuit" could anyone tell me what that means?
1973 cadillac eldorado convertible
1963 cadillac deville convertible
1966 cadillac Calais sedan
1970 buick wildcat

Offline Tonyv_73

  • Posts: 61
  • Name: Anthony Vanacore
Re: 1981 Eldorado 368 8-6-4 code 18
« Reply #1 on: June 15, 2017, 08:48:15 PM »
Does anyone know what this means?
1973 cadillac eldorado convertible
1963 cadillac deville convertible
1966 cadillac Calais sedan
1970 buick wildcat

Offline Glen

  • Posts: 2194
    • CLC Member
      CLC Member #727
  • Name: Glen Houlton
Re: 1981 Eldorado 368 8-6-4 code 18
« Reply #2 on: June 16, 2017, 01:27:07 AM »
I googled “open crank signal circuit” and got this:
… code for the engine control module (ECM) detecting an open or short circuit in the crank position sensor signal wire or sensor to the ECM.

It is from this page:
https://www.yourmechanic.com/article/p2617-obd-ii-trouble-code-crank-position-signal-output-circuit-open-by-jay-safford
While that is an OBD II page I think the meaning is the same.  You need to check the crank sensor to see that it is connected and the wiring is intact and not shorted.  If the wireing is good, then the sensor is bad and should be changed. 
Glen Houlton CLC #727 
CLCMRC benefactor #104