trouble code 42
Thread Starter
Instructor
Joined: Jul 2007
Posts: 229
Likes: 0
From: FT Lauterdale Florida
trouble code 42
hey guys, I keep getting code 42.
its the only code ive got,
I just replaced,
plugs
cap + rotor
coil
igniton control module. ( boomerang shaped thing that goes under the rotor on the dist. )
and I keep getting the code 42.
what else am I missing?
could it be the wires that conect all that stuff gone bad?
or is it more likely the ecm or chip?
what exactly does code 42 mean?
its the only code ive got,
I just replaced,
plugs
cap + rotor
coil
igniton control module. ( boomerang shaped thing that goes under the rotor on the dist. )
and I keep getting the code 42.
what else am I missing?
could it be the wires that conect all that stuff gone bad?
or is it more likely the ecm or chip?
what exactly does code 42 mean?
- 1986 Original Owner -
Joined: Apr 1999
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From: North Yorkshire, England
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Read all about code 42 in your GM shop manual section 6E, but basically it means the ECM is seeing a voltage out of range on the EST Bypass line. The range is dependent on mode (Starting/Running). The Bypass line is the one disconnected when setting timing and this causes a code 42. As part of the procedure, the ECM should be disconnected for several seconds to clear the code. You need to start by clearing the code and see if it returns. Also make sure the Bypass line has been reconnected.
Thread Starter
Instructor
Joined: Jul 2007
Posts: 229
Likes: 0
From: FT Lauterdale Florida
I believe this to be my est connection,
its hooked up, - I did clear codes. went for a drive again today.
code 42 came back. its the only code im getting.
do I have both of theese hiding in my car somewheres?
are they up under the dash?
http://www.ecklers.com/product.asp?p...2&dept_id=1306
http://www.ecklers.com/product.asp?p...5&dept_id=1306
im gona be kinda mad if I have to replace both of those units.
if so then every single electric part of my ignition will have been replaced looking to find the cause of this code 42.
( im sorry, im just getting frustrated )
its hooked up, - I did clear codes. went for a drive again today.
code 42 came back. its the only code im getting.
do I have both of theese hiding in my car somewheres?
are they up under the dash?
http://www.ecklers.com/product.asp?p...2&dept_id=1306
http://www.ecklers.com/product.asp?p...5&dept_id=1306
im gona be kinda mad if I have to replace both of those units.
if so then every single electric part of my ignition will have been replaced looking to find the cause of this code 42.
( im sorry, im just getting frustrated )
Instructor
Joined: Oct 2006
Posts: 141
Likes: 7
From: Deltona Florida
Code 42 is set when the engine is running at > 600 rpm and there is no pulse on the white wire from the ECM to the ignition module (CKT423) for more than 200 milliseconds.(At 2000 rpm, 200ms represents about twenty seven spark plug firings.) Code 42 can also be set if the voltage on the tan and black wire (CKT 424) remains low (near zero) or goes low while the car is being driven. the ignition module is designed to ground out the EST signal which travels down the white (CKT 423) wire unless there is 5 volts on the tan and black wire(CKT 424)this locks the timing at a fixed positon while the engine is being started.
common causes of a code 42 include bad connections, frayed or broken wires and rubbed thru insulation on either the tan and black, white, or purple and white (CKT 430) wires running between the ignition module and the ecm.
you need to troubleshoot and replace either the ignition module, ECM, or the wires between the ECM and ignition module
common causes of a code 42 include bad connections, frayed or broken wires and rubbed thru insulation on either the tan and black, white, or purple and white (CKT 430) wires running between the ignition module and the ecm.
you need to troubleshoot and replace either the ignition module, ECM, or the wires between the ECM and ignition module
