Dashmaster

Code E041 Cam Sensor Circuit

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Ronnie yours would have been in sync for the Sensor because the computer knows what the last know location was. Since my battery has been unhooked and the ECM once, mine is shooting in the dark for the 1 and 6 change of getting it right. Ronnie, I have removed the loom and traced back to the splices, re-did the splices. All voltages are correct except for the Cam Sensor A at ICM (old sensor 9.75 volts, new sensor 5 volts sensor plugged in. At cam sensor plug I have not see more then 5 volts on A.  I never see a pulse signal on brown\white wire at ICM or BLK to ECM, voltage to ECM on BLK is low 4.86 volts.

Continuity has been checked on all the wires for short and high resistance.

Edited by Dashmaster (see edit history)

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30 minutes ago, Dashmaster said:

- All voltages are correct except for the Cam Sensor A at ICM (old sensor 9.75 volts,

- new sensor 5 volts sensor plugged in.

- At cam sensor plug I have not see more then 5 volts on A. 

-I never see a pulse signal on brown\white wire at ICM or BLK to ECM, voltage to ECM on BLK is low 4.86 volts.

 

I did some testing on my car this morning so you can compare your readings to mine. My engine is running good and I don't have a code E041.

 

First I disconnected the plug from the came sensors and tested pins A-B. The meter read 6.5 VDC which according to the FSM is low.. Testing pins B-C read 10.8 VDC. They should both test 8-10 volts.

 

Then I back-probed terminal M (Gray/Red wire) and terminal F (Black wire) on the ICM connector. With key ON, engine OFF my meter read 4.88 volts DC. When I started the engine the voltage fluctuated between 4.51 and 4.53 volts.

 

I did these tests with two different DVMs and an old analog meter. The results were identical with all the meters I tried using terminal M for the ground and also the negative battery terminal for ground. The results were the same.

 

If I went strictly by the flow chart in the FSM and expected 10 volts I would think my cam sensor was bad or my ECM was bad but that is not the case. I have no E041 and the engine is running fine.

 

You said you got a reading of 4.83 VDC on the black wire as I did. Could you test it again and see if the voltage drops to 4.51 and continuously fluctuates between that and 4.53 VDC like mine did?

 

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15 hours ago, Dashmaster said:

If it did not miss under load I would drive it, Its not bad with AC off, But being so hot the AC makes it worse to drive. I did not take it to Allentown. I did go up Thursday for the Rendezvous, and visit show site. I have some pictures from up there not may need to resize them.

 

If it were me, I might be inclined to disconnect the cam magnet sensor connector, then drive it under load to see if there's any change in the "miss under load".   Sometimes voltage readings at idle or ign on w/o engine running do not correlate to conditions present at say 2000 rpm.  You might find tht by disconnecting it, you don't get sequential injection but it won't stumble under load.   I could be wrong but it might be worth the 5 minute investment 

 

 

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14 hours ago, Dashmaster said:

For Reference.....Plugs, Wires, ICM, TPS, ECM, IAC was new ( 1 year old) cleaned again, EGR swap,OX, Coils 3, 6 months old, other older all tested with meter good.  

 

 

 

 

The suck part can sometimes be, a new component has a fault.  Maybe, if you still have the old ECM, try swapping it.   I've seen more than a couple frustrating repair attempts when a newly replaced component itself was the issue.

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Ronnie your voltages are so very close to mine. I am using battery ground for meter. Had car running and was in closed loop. Tested from ECM BLK 4.86 at idle and sometimes a variance of .01. Raise RMP's, voltage went to 4.9 very little variance on meter. Switch to 2KHZ setting on meter and you can see a frequency that varies with engine RPM. I think the ECM is reading the frequency being carried by the voltage.

Frequency reading at idle are about .5KHz, Will increase with RPM and will go off scale on my meter,

 

The E041 was the only code showing so after all the work I did for MAF and all the swapping of parts and testing for it  I have eliminated all Ignitions parts for the cause of the miss. The car now will start fine, run for a bit, move it some, It will stumble at idle several times. Car stalled today, restarts fine. Took very short drive, stumbles bad with foot into it.

I did another Fuel Pressure test today since during the MAF they were barely in spec. I am getting 38 psi key on,  car started at idle 33psi, give it some throttle peaks at 3.8.

I think the fuel pump is giving up the ghost.

I also agree that the E041 is not causing the miss under load.

This topic can be closed.

 

Thank You All with the information you have provided for ideas to check.

Ronnie special Thanks for taking the time to test your car for me, I really appreciate the effort. Especially since the data you and I are getting do not match the FSM at all.

Everyone have a Great Day!!

 

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52 minutes ago, Dashmaster said:

Ronnie special Thanks for taking the time to test your car for me, I really appreciate the effort. Especially since the data you and I are getting do not match the FSM at all.

 

I was happy to try to help. Sorry that your problem was not resolved.

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The vast majority of the time, stumbling under load in a GM car is due to high resistance in the secondary ignition circuit.   I use my 200,000 miles driving experience on three different supercharged Rivieras as a reference.  In both cases I encountered it, one turned out to be a bad plug wire, the other time it took me a long time but I pulled all the spark plugs and measured their resistance and one was waayyy high, like 700k ohms.   But also don't confuse tranny shudder with stumbling, there's a subtle but detectable difference btw the two.  You mentioned you did the wires, but don't trust chinese wires or even american ones, sometimes red herrings slip through the QA dept.   do you have one of the devices in the link below ?   when necessitated, I prefer to use mine when its pitch dark outside :)  I didn't mention this previously b/c I'm really not that smart and it could be something strange and unique to the Reatta associated btw an 041 code and a stumble under load.   Just throwing in my $1.23.   (that's my "two cents", adjusted for "inflation", $0.02 ain't what it used to be)    This:  http://www.handsontools.com/Lisle-19380-Spark-Indicator_p_6816.html?gclid=COvm6uvDo84CFYcCaQodH0IPGQ 

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Something to look at if you haven't looked yet, is the condition of the cable wrap.

 

These cars are old enough that the cloth tape wrap can be turning to dust or just plain falling apart. The wires don't have to rub through the insulation to have movement be a problem, they just need to be flopping free next to a wire carrying power. The technical term is hysteresis affect, the simple explanation is your wire bundle becomes a mini alternator and if that micro voltage surge of electricity is tickling a sensor wire carrying a microvolt signal, it can tell the engine controller all sorts of strange things.

 

 

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Having just been down the engine shutter/stumble/misfire under moderate load game, I will chime in.  

While a "Current"  E041 certainly indicates an issue somewhere either in the cam sensor, the interrupter, the wiring, or the ICM (Ignition control module), I can attest to the fact that ANYTHING that can negatively impact the ICM can trigger a false E041.  About 2 years ago I did the Padgett repair method for my disintegrating cam sensor interrupter (better know as the magnet).  The E041 started out as intermittent and over time completely failed, but NEVER caused ANY discernible performance issues, at least nothing detectable (remember that the ECM has a fail safe fallback in the case of a missing cam sensor signal).  I replace both the interrupter and the sensor which fixed the E041, but then starting about 6 months ago, I started finding periodic history of an E041, but NEVER a current failure indication.  My first thought was that maybe I either had a wiring issue OR possibly the magnet fix was failing.  Then I started having issues with the infamous engine dying, won't start, allow to cool, engine starts once again.  Given that the ICM is invariably the root cause of this problem, I replaced the 3 year old ICM which seemed to fix the engine die off issue, but I now was detecting engine misfire under moderate load, low rpm conditions, which pointed back to the secondary side of the ignition system.  I was also still getting those periodic E041 history codes.  As I already had a new ICM, I replace the coil pack, then the plug wires, but still the misfire was occurring.  I then replaced the 3 year old Pulstar plugs and bingo, the misfire vanished.  One of the plugs showed signs of breakdown at the exterior junction of the plug-to-porcelain interface.  With the misfire finally fixed, I cleared all the codes and with a couple of months of use now, not a single E041 code has popped up in history.

 

So the point is, that long before the failing spark plug caused ANY discernible engine condition, it was enough to trigger the ICM to drop the cam sensor signal output to the ECM periodically setting the E041 history.  While I don't have any proof, I do wonder if the plug that was failing was causing the coil pack to internally arc between the secondary and primary coils (a known design weakness in the original OEM designs) which led to the failure of the ICM which is of course feeding the coil pack primary windings.  As the ICM acts as a signal buffer between the cam sensor and the ECM, again, anything that impacts the ICM CAN cause an E041 to pop up. 

 

I can add that while the E041 is a nuisance, the loss of the cam sensor signal never caused my 3800 to ever present even a slightly rough idle.  I did on occasion experience it not starting quite as quickly as expected which may well have been due to the sequential fuel system being out of sync with the engine timing, but again, the cam sensor circuit seems to have little impact on the overall performance and I doubt is involved in your misfire problem.  

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On August 4, 2016 at 8:32 AM, drtidmore said:

 As I already had a new ICM, I replace the coil pack, then the plug wires, but still the misfire was occurring.  I then replaced the 3 year old Pulstar plugs and bingo, the misfire vanished.  One of the plugs showed signs of breakdown at the exterior junction of the plug-to-porcelain interface.  

 

Yes !!    I went through the exact same sequence once trying to find a cause for a miss under load - ICM, coils, wires.... and finally found the middle plug in the rear with the same breakdown you described, except mine was AC brand.    All that time & $$ spent, over a ... spark plug !!    Well, at least I got a spare ICM out of the deal, which I recently installed on the Reatta so it wasn't a total waste....

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