Thanx so much for setting all this straight. My brother had it hooked up b4 i bought the car, which was where the codes first appeared. He replaced the coils/assembly with stock parts and a few months later the light came back on, and i took it to a friend who hooked it up and only the cat code came up. Now, on Wed, when AZ hooked it up, 3 codes came up. I will go to Advance over the weekend and have them write down the actual codes for me. Again, thanx!


Krissy

 

Hey everybody...newby here trying to get some (duplicate?) info. Go ahead, flame me, I don't know what it means so I won't be offended.

Recent purchase of a 1999 SL....base model, manual everything. Only option is AC. It has @126,xxx miles on it. I have replaced sparkplugs, EGR valve, front Oxygen sensor. OBD2 codes were P0133 and P1404. This morning I have a pending code P0341. I have tried to look for the replacement part, only to be directed to a crank position sensor.

I know just enough about things to hurt myself and put other people in danger (think electrical outlet replacement). I'm thinking that the camshaft sensor deals with the camshaft and the crankshaft sesor deals with the, um, crankshaft (the other side of the pistons). Is it just part of the overall conspiracy to get money from me?

Any/all help is gretly appriciated
Erik297400

 

Erik297400 --

Naaaaaa, we don't fame anybody in the summer -- too hot already.

Crankshaft Position Sensor (CPS) inputs timing signals to your car's computer. They can go bad, and usually result in non-starting or really lousy performance.

Disconnect the wiring from the sensor, and set it aside. Connect the leads of an ohmmeter to the sensor and check the reading (700 to 900 ohms). Replace if necessary.

The possibility does exist that this sensor is cracked (causing trashy signals to the computer), even though a static resistance measurement seems OK

 

P0133 -- Oxygen Sensor Circuit Slow Response (Bank1, Sensor1). Front 02 sensor not responding quickly enough
Probably replace Front O2 sensor. Use a Denso -- the Bosch ones suck.
I'm gonna guess you didn't use a Denso OEM replacement......

P1404 I believe is "EGR pintle stuck open" technically, but appears to be a common issue with GM vehicles and is often a false code due to the PCM's perceived change in the closed position as the pintle wears.

The following I found while surfing the web -- it indicates that replacing EGR valve often does not resolve the situation.

No idea if the following is worth anything---just passing it on:
_____________

Many GM built cars have a tendency to have the 'Check Engine Soon' light come on as a result of DTC code P1404. P1404 is described as EGR valve pintle stuck open, which in most cases is a false alarm. I had this happen with my '01 Grand Am. A little bit surfing on internet reveals that GM has a solution for the problem, a re-flash for the car's computer.

A software re-flash as a fix kind of indicates that the vehicles with this problem were built with it but I don't think GM will be re-flashing cars outside warranty for free. They will want their $100 for it.

Some hands on people I found had purchased a new EGR valve and changed it but the problem remained.

Possible reason (very likely) for the false P1404 code is that the plastic piston of the EGR valve position instrument (LVDT?) wears over time and starts reading a different position at valve closed than what it was when the EGR valve was first installed.

When the car was built and the computer circuits energized for the first time the computer learned the EGR valve closed position signal from the valve position instrument that is built on top of the valve itself. Over time, when the instrument wears, a slightly different signal is sent to the computer and when it differs enough from the 'Valve Closed Signal', that the computer had learned, the trouble code P1404 is set and the 'Service Engine Soon' light comes on.

Replacing the EGR valve with a new one does not necessarily fix this problem because the 'Valve Closed Signal' between valves is slightly different and it is just pure luck if your new valve would give a 'Valve Closed Signal' close enough to your original valve's signal not to set the trouble code. This is why the new EGR valve 'Valve Closed Signal' must be re-learned by the computer.

So, what this all means is that if the P1404 is a false code meaning that the valve pintle is not stuck open, then new 'Valve Closed Signal' can be re-learned by the computer using the old valve.

For fixing this problem the tool you need to have is a simple OBD II code scanner that can be used to erase trouble codes. There are many scanners of different price range on the market. I purchased one from AutoZone for about $90.

A code scanner is a very handy tool to have and I recommend everybody who is just slightly hands on type of a person to get one. It will end up saving a lot of money over time.

The fix goes like this:

1. Disconnect the wire harness from the EGR valve.

2. Turn key ON and erase the trouble code(s) from the car's computer AND TURN KEY OFF IMMEDIATELY WHEN THE SCANNER SAYS CODES HAVE BEEN ERASED. DO NOT TURN KEY ON BEFORE YOU RE-CONNECT EGR WIRE HARNESS.

3. Re-connect EGR wire harness and your problem should be fixed.

I learned this fix from OBDII.COM where carfixer and kozloski discussed it and I think kozloski was the one who provided the solution, so thanks to them.

There was also other people stating that this fix really works. Now I have joined this group of people as I got mine fixed using this trick also.

I believe erasing codes with wire harness disconnected and turning the key OFF right after P1404 code has been erased re-sets the 'Valve Close Position' reading in the computer and triggers computer to re-learn position next time the key is turned ON.

________________

Please keep us informed. We'll troubleshoot P0341 if it is still present after the other codes are gone....

 

DERF,

Hey dude, thanks for the info. Agree with the statement about everyone having a code reader. I don't have the most sophisticated one, but it is helping me do my own repairs (eBay for something like $17.50). But, then again, THAT might also be part of the problem

My original '92 SL had the EGR valve issue that would intermittantly cause the SES light to come on. This started at around 85k miles and persisted until (RIP) 339,005. I had the dealer replace EGR once, then I learned to ignore the SES light. It would come on in a cold start up, then go away after warming up, sometimes days, sometimes weeks. Definately will try the above trick if problem persists. 50 mile ride home last night from work, the P0341 code didn't pop up in my reader.

Guilty, I used BOSCH EGR and Oxygen sensor from Advanced Auto Parts. I bought the car used for $1150, and while I want this to run for a couple of years, I also am learning how to do more work on it myself. REALLY, REALLY happy I found this forum.

Stll looking for info: Does the SL have a camshaft sensor? I may have missed it in your answer.

 

no camshaft sensor in the s cars. This code is a sign of ignition related issues but may be falsely triggered by other things so that's why I didn't go into detail

I was only bashing the Bosch 02 sensor -- I have no experience with Bosch EGR valves.....

Please let us know if the above 1404 is fixed by the sneaky trick....

 

Thanks all. I replaced the spark plug wires and, magically, the pending code problem went away. The previous wires were probably original with @10 years worth of use on them.

Passed inspection so I'm a happy camper. Gas milage is running 34MPG with mixed driving conditions (highway/local roads)

 

glad to hear you are back running strong and that it was a simple fix....