Engine Codes 326 & 341

I had posted a couple of previous messages asking about harsh shifting on my
son's 1996 Saturn SL1 (1.9L single cam), but no one seemed to have any
advice to offer so I replaced the Torque Axis Mount (was going bad the new
one definitely reduces engine movement on shifting), then tried the
"reverse slam" fix from the SaturnFans forum, and then crawled under the
vehicle and looked at the lower motor mounts, CV joints, etc - but I still
can't find out what is wrong.

So, I broke down and took the vehicle to a reputable local Transmission
place and they told me that after scanning the computers, there are no
transmission faults, but that the engine has the above two error codes in
the memory. I have been able to determine that the codes are as follows:

Error 326 - Knock sensor signal out of range
Error 341 - CPS Circuit out of range

I am presuming that the CPS is the Crank Position Sensor. Is this correct
and if so, where is it located on this engine? My follow up question is
has anyone seen these errors previously and if so, what is the likely cause
and are they related? Which one should I go after first.

All this said, there is no "Check Engine" or "Service Engine Soon" idiot
lights illuminated and the engine seems to run very well, smooth, and as
powerful as it ever seems to have been. It even idles smoothly too. Not
bad for 125K miles....

Any advice on what to look at or how I can troubleshoot these codes would be
very much appreciated. The trans place said to get them fixed first since
from their experience a lot of times the transmission may not work right on
Saturn's if the engine or engine computer are having problems. Thanks in
advance for your thoughts.

Bob

 

Go to a Saturn dealer, have a free coffee and read the (three) factory
manuals (cost $180 to buy) if you ask nicely they will make you copies of
the important maintenance data from the manuals. While you are there you
can get their advice (usually for free) and price the factory parts. They
might even read the engine codes (for free at some dealers) to confirm the
initial reading. The free stuff may make the higher parts cost acceptable.

You can then price jobber parts and can decide if you have the tools and
desire to continue the repair yourself. It isn't rocket science but you
should follow the trouble shooters rule, to only change one thing at a time,
and save and mark the old parts until you are sure they are defective.

Don't place blind faith in the codes, often a bad ground or connection can
give false codes and a good cleanup would be a cheap first step and may mean
you will not replace serviceable parts.

 

Thanks for the advice which is all very good. I was hoping someone had seen
the codes before and could tell me that a defective cam shaft position
sensor might set the knock sensor or vice versa.

Regarding the bad grounds, this is also excellent advice and I had
considered that as well as a bad battery (low voltage) might cause the
electrical errors/problem as well.

Not sure what I will do just yet, still hoping someone can provide some
experience to be my guide.

Bob

 

All powertrain codes for obdII start off with P and contain 4 digits
after that.

P0326 Knock Sensor
P0341 Camshaft Position Sensor Circuit

Your first post said crankshaft, not camshaft.

Yes these can be related but 1996 Saturn SL1's dont use cam sensors.
They use compression sense which uses the cam code when something goes
wrong with it. If your engine didnt know when to apply spark it could of
"knocked". Or the knock could of fooled the compression sense part of
it. You say you have 125k miles on it? When was your last tune up?

 

Yes, the vehicle has 125.5K miles, but is very well maintained and was tuned
with new wires and plugs (correct .040 gap, IIRC) about 12K miles ago. Yes,
the two codes you are referencing P0326 and P0341 are correct and I had
abbreviated them for simplicity to just the last three digits. On P0341, my
Haynes book says this is a Cam Position Sensor, but the trans place said it
was a CPS error, and the same Haynes states CPS is located on the firewall
side of the engine block (just to the left of the Knock Sensor) not in the
head, so I think this confirms it is a Crank sensor and not a Cam sensor and
that the Haynes is likely incorrect. (From past experience, Haynes and
Chilton make a lot of these kinds of "small" mistakes ... I'd rather have
the FSM, but this is my son's vehicle and was purchased used. As you state,
I do not see a Cam Position Sensor anywhere on the 1.9L SOHC.

I checked and both the Service Engine Soon and Check Engine lights
illuminate when the key is turned on before starting so they are not burned
out. I do not own an OBDII code reader, so I only have the two codes from
what the transmission place told me since neither of these "idiot" lights
are currently illuminated. From what I have read, these may have been
stored in the "history" portion of the CPU memory and not in the "general"
area (last 50 ignition key starts) so they may have occurred a long, long
time ago. If anyone understands the methodology used to store the history
and can confirm that my removing the battery cable would not have reset
these codes, let me know.

What I have tried since getting the vehicle back from the trans place this
morning:

I checked the battery and it measures a full 12.8V after sitting overnight
and without the engine running. When I start the vehicle, the voltage
jumped up to 14.3V so it appears the alternator and charging system are
working as designed. When I stopped the engine a few minutes later, the
battery voltage measured 13.2V so I assume the battery is also good.

I then removed both battery cables, the fender mount ground, and both engine
block ground cables and thoroughly wire brushed them all, cleaned with
electrical contact cleaner, and then re-tightened the connection bolts.
Some were slightly dirty, but nothing really looked all that bad. This had
no impact.

I am now getting ready to raise the vehicle and go back under to take a look
at the knock sensor and CPS (Crank Position Sensor). I intend to remove
those connectors and use the contact cleaner to clean them off then
re-connect. I don't really think this is what is causing the problem since
the engine starts right up (would not start if CPS was bad right? Any one
know if it could go partially bad, allow the vehicle to start and not set a
code?) and is running very smoothly.

The automatic shifting is extremely harsh. It almost seems like someone
just slammed into the rear of the car when it shifts, but these are at the
pre-assigned speeds (speedometer is working just fine) and the
normal/performance switch seems to do what it always did by delaying the
shift and allowing the engine to rev slightly higher to develop more power .
I am having a hard time understanding why the transmission place said
nothing is wrong with the trans (there were no trans codes set) and to
correct the engine problem before bringing it back to them.

Can anyone who understands the mechanics involved in changing gears (both at
rest from Park to reverse as well as while driving from 1-2-3-4) explain
how some type of engine sensor or computer malfunction would cause the very
harsh slamming we are experiencing?

As always, thanks in advance for your thoughts and ideas.

Bob

 

First off
CKP = Crankshaft Position Sensor
CPS = Camshaft Position Sensor

Have you played with the connectors to your transmission? You might want
to inspect those.

 

Haynes lists CPS as the former ... although that is not really relevant. I
think we agree there is no Cam position sensor on this engine.

I checked the connectors to both senders and they looked clean and dry so I
reconnected them. At this point I am back to my original assumption that it
may be a motor mount so am currently looking at the lower mounts. I've
removed both inner fender splash shields and plan to have my wife move
between the gears while I can clearly see the amount of movement. At this
point I suspect that the rubber mounts may be dried up and shrunken causing
the excessive movement.

With regard to the transmission connectors, I have not looked at those just
yet since they scanned the codes and all reported normal so I did not think
the problem was with them. There is a sensor of some kind right at front
near the transmission filter. Possibly a temperature sender? Oh well, that
will be next.

Thanks again for the ideas.

Bob