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Chrysler Repair/'94 LHS no start: code 43


QUESTION: hello roland,

1994 LHS

Can a failing BCM cause a crank no start situation.

lights on dashboard are all on, locks on doors turn off and on randomly, and this car did come with a stock security system that i dont use anymore.

im thinking that the BCM is causing the anti theft system to malfunction as well.

prior to this i had replaced a bad PCM because of a burnt capcitor. had a crank no start situation as well car was working fine.

i got no spark, no signal at cam and trans sensor, relevant relays all check out, i can hear the fuel pump prime

could it be the BCM?

ANSWER: Hi Russell,
I doubt that the BCM is causing a no start situation. The anti-theft system allows the engine to start but then it cuts it off after a second or so.
The lack of a cam or a 'trans' sensor (did you mean crank sensor?) signal suggests that you may not have an 8 volt supply to those sensors on their orange wire. So check that out. It could be a short in the supply wire or a PCM problem about that 8 volt supply.
Have you tried for fault codes using the ignition switch: "on-off-on-off-on and leave on"  doing that in 5 seconds or less elapsed time. Then watch the check engine light, which remains "on", to see it begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat the process to assure a set of accurate flash counts. Let me know the counts in order of appearance.
What do you mean by 'all lights on the dash are on'?

---------- FOLLOW-UP ----------

QUESTION: hey roland,

here is what i found,

got flash codes. i noticed that gas gauage would go up and down during this process.

12 21 21 21 21 43 66 55

so i got the begining 12 code four oxy sensors and ignition coil code, ccd bus whatever that is, then the end message.

any ideas?

First make sure that you have 8V on the orange wire to the cam and crank sensors, but I notice that you didn't get an 11 or 54 which are the two no engine rotation sensors so you may indeed have working cam and crank sensors (those can't be 'seen' while cranking over the engine, by the way, only by rotating the crank by hand).
Then I would check the primary and secondary winding of the three ignition coils: primary should be 0.45 to 0.65 ohms; the secondary windings should measure 7,000 to 15,800 ohms when measuring between the tower pairs (3 to 6, 1 to 4, 2 to 5).
Then see if you get spark and can get it running. Dealing with the 21 code and the 66 code then should be done.

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Roland Finston


Free fast answer to your repair question about a Chrysler/Dodge/Plymouth car, minivan, SUV, or truck. Problems with electronically controlled engines and transmissions as well as body wiring problems are my specialty. This free troubleshoot advice forum helps you diagnose faults, minimize repair costs or do-it-yourself.

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