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.
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.
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.
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.
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