Code 41 -- I am nearly bald!
Thread Starter
Instructor
Joined: Dec 2005
Posts: 108
Likes: 0
From: Gainesville Florida
Code 41 -- I am nearly bald!
Well I am pulling my hair out. My car still will not crank after replacing the ICM, and the computer is still throwing code 41. Does anyone have experience with this code?
My next guess is that it could be the crankshaft sensor -- but I have no clue where to find it our even how to replace it.
Any advise is appreciated....
My next guess is that it could be the crankshaft sensor -- but I have no clue where to find it our even how to replace it.
Any advise is appreciated....
Pro
Joined: Jun 2003
Posts: 618
Likes: 0
From: Kingston Springs Tn
Well I am pulling my hair out. My car still will not crank after replacing the ICM, and the computer is still throwing code 41. Does anyone have experience with this code?
My next guess is that it could be the crankshaft sensor -- but I have no clue where to find it our even how to replace it.
Any advise is appreciated....
My next guess is that it could be the crankshaft sensor -- but I have no clue where to find it our even how to replace it.
Any advise is appreciated....
Racer
Joined: May 2005
Posts: 472
Likes: 1
From: looking for my insanity state of confusion
code 41--electronic spark timing (open or shorted circuit)
did you check voltage the end white wire on the coil driver(terminal B)? Should be .5 volts with ignition "on". Is more than .5 volts present?
Yes or No answer please(from the red service manual)
did you check voltage the end white wire on the coil driver(terminal B)? Should be .5 volts with ignition "on". Is more than .5 volts present?
Yes or No answer please(from the red service manual)
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Forgetting about the code41 for a moment:
Did you check your fuel pressure at fuel rail ?
Did you check for spark at any of your plugs ?
Autozone should have equioment to test the ICM they sold you.
Did you check your fuel pressure at fuel rail ?
Did you check for spark at any of your plugs ?
Autozone should have equioment to test the ICM they sold you.
Racer
Joined: May 2005
Posts: 472
Likes: 1
From: looking for my insanity state of confusion
A code 41 will disable the injectors to prevent flooding of the engine.
12 volts is way too much, the est range should be .5 to 4.5. Are you measuring the right wire? there are two of them, one goes to the coil and one to the ecm(which is the one to measure)if so, the next step in line
ignition "off". disconnect ecm connector "A" (yellow or grey color), ignition "on" is voltage present?
if not-faulty ecm. if yes short to voltage in est circuit.
This is coming from the FSM for a 92. hope it all turns out all right for you.
Another thing to check also is the condition of the wiring all around the icm, I've recieved an esc fail code and found the wire to my coolant temp sensor was split. after I replaced the wire everything ran fine.
12 volts is way too much, the est range should be .5 to 4.5. Are you measuring the right wire? there are two of them, one goes to the coil and one to the ecm(which is the one to measure)if so, the next step in line
ignition "off". disconnect ecm connector "A" (yellow or grey color), ignition "on" is voltage present?
if not-faulty ecm. if yes short to voltage in est circuit.
This is coming from the FSM for a 92. hope it all turns out all right for you.
Another thing to check also is the condition of the wiring all around the icm, I've recieved an esc fail code and found the wire to my coolant temp sensor was split. after I replaced the wire everything ran fine.
Last edited by vetteracer92; Aug 19, 2008 at 10:29 PM.
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Thread Starter
Instructor
Joined: Dec 2005
Posts: 108
Likes: 0
From: Gainesville Florida
Okay, I am following the same troubleshooting chart from the manuals.
Code 41 set ---> Yes
Is Voltage in terminal B > .5? ---> Yes (12V)
Disconnect terminal B from ECM, still voltage? --> Yes (12V)
Result --> Short to Voltage in EST circuit.
I am very certain of the results, but I am not sure how to proceed from here. Anyone have any experience in how to determine the source of of the short in the EST circuit?
Code 41 set ---> Yes
Is Voltage in terminal B > .5? ---> Yes (12V)
Disconnect terminal B from ECM, still voltage? --> Yes (12V)
Result --> Short to Voltage in EST circuit.
I am very certain of the results, but I am not sure how to proceed from here. Anyone have any experience in how to determine the source of of the short in the EST circuit?
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
Okay, I am following the same troubleshooting chart from the manuals.
Code 41 set ---> Yes
Is Voltage in terminal B > .5? ---> Yes (12V)
Disconnect terminal B from ECM, still voltage? --> Yes (12V)
Result --> Short to Voltage in EST circuit.
I am very certain of the results, but I am not sure how to proceed from here. Anyone have any experience in how to determine the source of of the short in the EST circuit?
Code 41 set ---> Yes
Is Voltage in terminal B > .5? ---> Yes (12V)
Disconnect terminal B from ECM, still voltage? --> Yes (12V)
Result --> Short to Voltage in EST circuit.
I am very certain of the results, but I am not sure how to proceed from here. Anyone have any experience in how to determine the source of of the short in the EST circuit?
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Okay, I am following the same troubleshooting chart from the manuals.
Code 41 set ---> Yes
Is Voltage in terminal B > .5? ---> Yes (12V)
Disconnect terminal B from ECM, still voltage? --> Yes (12V)
Result --> Short to Voltage in EST circuit.
I am very certain of the results, but I am not sure how to proceed from here. Anyone have any experience in how to determine the source of of the short in the EST circuit?
Code 41 set ---> Yes
Is Voltage in terminal B > .5? ---> Yes (12V)
Disconnect terminal B from ECM, still voltage? --> Yes (12V)
Result --> Short to Voltage in EST circuit.
I am very certain of the results, but I am not sure how to proceed from here. Anyone have any experience in how to determine the source of of the short in the EST circuit?
Thread Starter
Instructor
Joined: Dec 2005
Posts: 108
Likes: 0
From: Gainesville Florida
This is very strange.
The wire from coil driver terminal D is white.
If I trace it through the wiring tubes all the way back to the ECM, it terminates as a blue wire into the ECM bulkhead pin A-12.
Is there possible some type of connector in between that will require to take the tubes apart? I am trying to avoid that because it looks like a full days work.
The wire from coil driver terminal D is white.
If I trace it through the wiring tubes all the way back to the ECM, it terminates as a blue wire into the ECM bulkhead pin A-12.
Is there possible some type of connector in between that will require to take the tubes apart? I am trying to avoid that because it looks like a full days work.
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
The only DTC 73 I find is an ABS/ASR code, "Spark Retard Monitoring Malfunction". The circuit in question runs from ECM terminal A22 to the EBTCM behind the drivers seat.
Based on your symptoms and testing so far I would look carefully at the wiring to ECM connector A (gray)
If you have done any work to the car recently make sure something in that area of repair did not pinch the harness, good luck.
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Check your coil:
There is definately an ICM connection to the ECM/PCM(The ICM must connect and break power to the coil at the right time. You can put a test light across the A and D terminals to test this - spin the engine and see if the light blinks on and off. The "timing" of terminal A and D is regulated by terminal B from the ECM. This "timing" is calculated by things like O2 sensor voltage feedback, TPS voltage, MAF or MAP voltage, etc. )
:
The EST, or Electronic Spark Timing is the signal that is generated from terminal B of the ECM. This EST signal ultimately controls when the coil fires(sometime before TDC of compression stroke for each cylinder. In this picture, the coil charge is being represented as current charge/discarge so the voltage is generated when the current goes from High(charge) to Low(discharge) state ).
The ECM will "shift" the EST pulse train back and forth as necessary to adjust timing(advance and retard). These are the timing adjustments as calculated by the various sensors. The 720 slots in the high resolution disc inside the Opti represent 1 degree of timing each.
There is definately an ICM connection to the ECM/PCM(The ICM must connect and break power to the coil at the right time. You can put a test light across the A and D terminals to test this - spin the engine and see if the light blinks on and off. The "timing" of terminal A and D is regulated by terminal B from the ECM. This "timing" is calculated by things like O2 sensor voltage feedback, TPS voltage, MAF or MAP voltage, etc. )
:
The EST, or Electronic Spark Timing is the signal that is generated from terminal B of the ECM. This EST signal ultimately controls when the coil fires(sometime before TDC of compression stroke for each cylinder. In this picture, the coil charge is being represented as current charge/discarge so the voltage is generated when the current goes from High(charge) to Low(discharge) state ).
The ECM will "shift" the EST pulse train back and forth as necessary to adjust timing(advance and retard). These are the timing adjustments as calculated by the various sensors. The 720 slots in the high resolution disc inside the Opti represent 1 degree of timing each.
Last edited by MikeC4; Aug 22, 2008 at 08:35 AM.
