FAQ: P0341 Camshaft Position Sensor (Cam Sensor / Timing Chain)

Has anyone had a trouble code PO341 camshaft position sensor A (bank 1 CKT Range/Perf)? My light stays on because of it and I don't notice any drivability/performance issues resulting from it. As of now, I don't recognize any patterns as far as the conditions it fails in. Could this potentially cause any harm to my engine if it's not fixed?

And does anyone happen to know if a code like this would cause me to fail emissions even if my actual gas readings are fine?

i have a close code; P0336 which is the crank position sensor. i dont know if the 2 problems are related, but i think it is just the sensor itself that is not sending the right signal to the pcm. i am hopefuly getting mine replaced this weekend. you say you CEL is on all the time? mine is only at random the trac light goes on.(like once a month it misreads)
i have no drivability problems and i dont think it is bad for the engine. i think there were a few people over at regalgs that had P0341 but i cant remember if they fixed it with just a new sensor.

I have no idea where to find it HELP please!!!!!!!! on the way home from skool when i got a check engine light and got the code read and then turns out its the camshaft sensor

FIXED just messed with spark plugs and it works now

SES light will turn off if the PCM doesn't see the problem after so many startups. Maybe it was a fluke. If the problem is for real, you'll be seeing the light again.

YESS i hope not tho

Well I actually just changed my cam sensor finally so time for a quick write up. 40 dollar part new. one 10mm bolt that holds it in. It's located just below and slightly to the left of the water pump pulley above the crank pulley. It is pretty much blocked by the mount bracket in that area so that makes it somewhat tricky to change but it's not too hard. Although it is probably possible to do without, loosening the main belt and removing the water pump pulley (4, 7mm bolts) helps enormously. For installation, no sealer or special prep is necessary. GM specifies the bolt be tightened to 44in lb although I believe you would be perfectly safe using a 1/4 in drive socket wrench like a normal person without steroids or muscular dystrophy and be fine. the plate is aluminum and won't cross-thread or crack unless you are a gorilla with a snap-on. I would suggest having a small pick-up magnet near by just in case. (i dropped the bolt a few times)

ive just removed the engine bracket about 6 rimes in th past 2 weeks. i could do it blind folded...... god only knows hom many times ive taken off the power steering pump.

97rivman wrote:

god only knows hom many times ive taken off the power steering pump.

I hear ya. It comes off easy, but lining it back up is a beotch. Im bent over like an idiot for 20 minutes trying to get those bolts back in.

Although I've been fighting with this PO341 mass air flow sensor (low input voltage) code for a while now, it looks like that code is a side-effect of the PO102 (cam sensor range/performance) code i've had since day 1. The mass air flow sensor and the cam sensor have already both been replaced with new parts. I checked all the related wiring and it's all good. Some unusual behavior turned my suspicion to the PCM. I just got an intense PCM today and tried it out. Got the same codes so PCM is off the list. (I plan on returning the PCM to intense)

There's really only one thing left that I (and a few other good mechanics and GM die-hards) can imagine to be the problem and that, unfortunately, is the cam sensor interrupter. It's basically a little magnet that's located on the cam gear and it is what gives the pulse signal to the cam sensor. I was really hoping this wasn't the problem because that means i'm supposed to remove the front cover and pull the timing set to replace this stupid little piece of shit. And being that its in a Riviera, i'm blessed with probably the smallest amount of room to work with in that area.

http://bellsouthpwp.net/p/a/padgett46/cammag.htm

that guy kind of found a trick to it where he didn't even remove the timing cover at all but I don't quite know if I want to try to do it that way. Being that I have already replaced the sensor and worked in that area testing the wires, I fully understand how much of a bish it would be to do all that stuff that he's talking about.

Any input?
and cam people, can you tell me what parts (gaskets, seals, no-brainer upgrades, etc) i need to have before i do it and what to watch out for?

YOU CAN PICK UP A CAM SWAP KIT FROM INTENSE WITH ALL THE TIMING CHAIN GASKETS THAT YOULL NEED. its not as hard as you would think, jack up the motor, remove the whole passenger side mount, and start removing stuff. Installation is the opposite. Its not gong to be a 1/2 hour job though.

Its a good thing at least that you wont have a problem returning the pcm to intense.

oh yeah, ill be posting some more of this for ya.


CIRCUIT DESCRIPTION

The camshaft position PCM input is produced by the ignition control module. The Ignition Control Module (ICM) produces the camshaft position PCM input by filtering the Camshaft Position (CMP) sensor pulses when the engine is running and Crankshaft Position (CKP) sensor sync pulses are also being received. The PCM uses the camshaft position PCM input pulses to initiate sequential fuel injection and to determine crankshaft position for the misfire diagnostic. The PCM constantly monitors the number of pulses on the camshaft position PCM input circuit and compares the number of camshaft position PCM input pulses to the number of 18X reference pulses and the number of 3X reference pulses being received. If the PCM receives an incorrect number of pulses on the camshaft position PCM input circuit, DTC P0341 will set and the PCM will initiate injector sequence without the camshaft position PCM Input with a one in six chance that injector sequence is correct. The engine will continue to start and run normally, although the misfire diagnostic will be disabled.

CONDITIONS FOR SETTING THE DTC

* The engine is running (3X reference pulses are being received).
* The ratio of 3X reference pulses to Cam pulses received by the PCM does not equal 6.
* The ratio of 3X reference pulses to 18X reference pulses received by the PCM equals 6.
* The above conditions are present for 600 engine revolutions.

ACTION TAKEN WHEN THE DTC SETS

* The PCM will illuminate the Malfunction Indicator Lamp (MIL) during the second consecutive trip cycle in which the diagnostic test has been run and failed.
* The PCM will initiate injector sequence without the camshaft position signal with a one in six chance that injector sequence is correct.
* If equipped with traction control, the PCM will command the EBTCM via serial data (CKT 800) to set an ABS/TCS DTC, the EBTCM will turn OFF traction control, and the EBTCM will illuminate the TRACTION OFF lamp.
* The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.

CONDITIONS FOR CLEARING THE MIL/DTC

* The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
* The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
* The DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

DIAGNOSTIC AIDS

An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Check for the following conditions:

* Malfunctioning Ignition Coil. Remove the ignition coils and inspect the ignition control module and coils for cracks, carbon tracking, or other signs that indicate that the coil secondary circuit is arcing to the ICM or ICM wiring harness. Refer to Ignition Control Module.
* Secondary ignition wire(s) arcing to wiring harness. Check the secondary ignition wires for carbon tracking or other signs of damage.
* Damaged harness. Inspect the wiring harness for damage.
* If the harness appears to be OK, disconnect the PCM, turn the ignition on and observe a voltmeter connected to the camshaft position input signal circuit at the PCM harness connector while moving connectors and wiring harnesses related to the ICM and the CMP sensor. A change in voltage will indicate the location of the malfunction.

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the Diagnostic Table.

2. Ensures that the malfunction is present.

21. Determines whether the malfunction is being caused by a missing camshaft magnet or a malfunctioning PCM The voltage measured in this step should read around 4 volts, toggling to near 0 volts when the CMP sensor interfaces with the camshaft magnet.
22. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.

CIRCUIT DESCRIPTION

The Mass Air Flow (MAF) sensor measures the amount of air which passes through it into the engine during a given time. The PCM uses the mass air flow information to monitor engine operating conditions for fuel delivery calculations. A large quantity of air entering the engine indicates an acceleration or high load situation, while a small quantity of air indicates deceleration or idle. The MAF sensor produces a frequency signal which can be monitored using a scan tool. The frequency will vary within a range of around 2000 Hertz at idle to about 10,000 Hertz at maximum engine load. DTC P0102 will be set if the signal frequency from the MAF sensor is lower than the possible range of a normally operating MAF sensor.

CONDITIONS FOR SETTING THE DTC

* The engine is running.
* TP angle is less than 50%.
* System voltage is greater than 8 volts.
* MAF signal frequency is less than 1200 Hertz.
* The above conditions are present for longer than 0.5 seconds + 400 3X reference periods (133 crankshaft revolutions).

ACTION TAKEN WHEN THE DTC SETS

* The PCM will illuminate the Malfunction Indicator Lamp (MIL) the first time the malfunction is detected.
* The PCM calculates an airflow value based on idle air control valve position, throttle position, RPM and barometric pressure.
* The PCM will store conditions which were present when the DTC set as Freeze Frame and the Fail Records data.

CONDITIONS FOR CLEARING THE MIL/DTC

* The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
* The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
* The DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

DIAGNOSTIC AIDS

A low minimum air rate can cause DTC P0102 to be set during deceleration. Check the minimum air rate as follows:

1. Run the engine until fully warm (above 85°C / 185°F).
2. Disconnect the IAC.
3. Install a J 37027-A IAC System Monitor.
4. With the engine idling, command the IAC valve to the fully extended position (0 counts).
5. With the IAC fully extended, observe the Mass Air Flow reading on the scan tool.
6. Check for conditions that can cause a low minimum air rate, including throttle bore and throttle plate coking if the Mass Air Flow reading is less than the following values:

o VIN K: 2.27 g/sec
o VIN 1: 2.95 g/sec

7. If the minimum air rate is less than specifications, clean or replace the throttle body as necessary. Refer to Throttle Body Assembly.

Check for the following conditions:

* Poor connection at the PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
* Misrouted harness. Inspect the MAF sensor harness to ensure that it is not routed too close to high voltage wires such as spark plug leads.
* Damaged harness. Inspect the wiring harness for damage.
* If the harness appears to be OK, observe the scan tool while moving connectors and wiring harnesses related to the MAF sensor. A change in the display will indicate the location of the malfunction.
* Plugged intake air duct or filter element. A wide-open throttle acceleration from a stop should cause the Mass Air Flow displayed on a scan tool to increase from about 4-7 gm/s at idle to 100 gm/s or greater at the time of the 1-2 shift. If not, check for a restriction.

If DTC P0102 cannot be duplicated, the information included in the Fail Records data can be useful in determining vehicle mileage since the DTC was last set. This may assist in diagnosing the condition.

TEST DESCRIPTION

Number(s) below refer to the Step number(s) on the Diagnostic Table:

2. This step verifies that the problem is present at idle.

5. A voltage reading of less than 4 or over 6 volts at the MAF sensor signal circuit indicates a malfunction in the wiring or a poor connection.
6. Verifies that ignition feed voltage and a good ground are available at the MAF sensor.

13. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.

ill get ya the wiring diagrams and troubleshooting guides when i get home.

old (late eighties) 3800 were prone to this (cam interrupter falling off). Never heard of it for the series 2. Here is how we did in on my brother's reatta, without removing the timing cover. Verify part #s as this is for an 1988.

http://bellsouthpwp.net/p/a/padgett46/cammag.htm

I'm going to try to find out tonight if that interupter is actually there or not by removing the cam sensor and looking through the hole with a mirror. We'll go from there. I think I may have seen somewhere that they can also loose enough of their magnetism to throw a code with lots of miles. So if the things still there, I'll take my ICM in to test it just to be totally sure it's not that.

I have been fighting with that P0341 for a year now, and have not located the problem yet. Mine is intermittent...it will do it 5 times in a day and then not do it for a month. I wouldn't be so quick to replace that magnet if the code is not set all the time. I had a service writer try to sell me a magnet replacement as well. When I asked, "Wouldn't the code be setting all of the time with the magnet missing?", I got a blank stare and then left. I have replaced the cam sensor, ICM, PCM, and front plug wires. I need to get to the rear wires when I change my plugs (hopefully this weekend). I'm also going to try to reroute or shield the ICM wires away from plug wires. Also, my traction control is never disabled when the 341 code sets on my Riv. After the plug wire change, the next diagnostic just might be a match.

to pull the front cover and replace this thing, do I need to pull the blower and/or lower intake too? I don't see why I would...

I wouldn't think so.

Dang, I need to buy those t/l sequencers...

1998rivman wrote:

I have been fighting with that P0341 for a year now, and have not located the problem yet. Mine is intermittent...it will do it 5 times in a day and then not do it for a month. I wouldn't be so quick to replace that magnet if the code is not set all the time. I had a service writer try to sell me a magnet replacement as well. When I asked, "Wouldn't the code be setting all of the time with the magnet missing?", I got a blank stare and then left. I have replaced the cam sensor, ICM, PCM, and front plug wires. I need to get to the rear wires when I change my plugs (hopefully this weekend). I'm also going to try to reroute or shield the ICM wires away from plug wires. Also, my traction control is never disabled when the 341 code sets on my Riv. After the plug wire change, the next diagnostic just might be a match.

I've been getting that code since I had the cam done. Has happend about 3-4 times since then. The light goes off and then the car will stall a little while later. Will be fine the next day though...

how many miles on the riv Pat? and do you have any other uncool behaviors besides the occasional stalling?

i had the code too but i just cleared it and it never came back.

turtleman wrote:

how many miles on the riv Pat? and do you have any other uncool behaviors besides the occasional stalling?

86,000. Thats the only thing that happends. It doesn't happen much and its usually fine later in the day or the next day.

Well I took the cam sensor off again today to look to see if the interrupter is there or not. It looks like it's there.


this pic is what I see with a mirror looking into the sensor hole (with the interrupter there)


thats a pic of the timing cover off that i found using google (just to get a reference of exactly what it all looks like)


thats the interrupter (courtesy of Intense)

My thoughts at this point are that even though the problem of loosing the interrupter has been remedied in the series 2 engines, with all the miles, heat/cold, beating, etc, the interrupter has lost enough of its magnetism that it's providing too weak of a signal.

any other thoughts before i spend about $200 replacing this stuff?

It occurred to me no sooner than on my way to work today that the symptoms of my problems can quite logically all point to a worn timing set. The noises i hear, the crappy transitional conditions, the trouble code(s), the miles, and the strangeness of the problem in general. All would very sensibly point to a chain tensioner thats bad or the chains just really stressed. Since I will be replacing the timing set with Intense's single set, and the new interrupter is on the way, I should be good once i replace it all. I'm going to try to get working on it this weekend.. possibly next weekend..

got all the hard parts and the gaskets and stuff. just need to do it.
sure would be nice if i had already gotten my service manuals for this...