CEL Diagnosis
02-28-14, 10:35 AM
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CEL Diagnosis
G'day folks. I purchased a 98 Lexus GS400 a couple of weeks ago. The car is in great condition, especially for it's age. The previous owner did well taking care of it...garage kept which is important in this Texas sun.
Not too long ago the CEL came on. The codes pulled were P0446, C1256 and C1233. I know the first one is tied to the EVAP system. I checked the hoses in the front and everything seems alright. I will go ahead and buy a new gas cap. Where else should I be looking? I'm trying to do as much as I can before making the decision to go to the dealer. I'm not opposed to the dealer, it's just that they're 70 miles away.
The other 2 codes, C1256 and C1233, I have no idea other than it's tied to the ABS system. Any input would be appreciated. I haven't noticed any difference in the drive, but I've only had it a couple of weeks. There are no other lights on indicating any other problems. Could this be an electrical short somewhere?
Thanks in advance for any input and insight towards this. In the mean time I will continue to scour through the threads in hopes of finding something. It's a great car and I love driving it. It's got 181k on it and I hope to at least double that myself!
Not too long ago the CEL came on. The codes pulled were P0446, C1256 and C1233. I know the first one is tied to the EVAP system. I checked the hoses in the front and everything seems alright. I will go ahead and buy a new gas cap. Where else should I be looking? I'm trying to do as much as I can before making the decision to go to the dealer. I'm not opposed to the dealer, it's just that they're 70 miles away.
The other 2 codes, C1256 and C1233, I have no idea other than it's tied to the ABS system. Any input would be appreciated. I haven't noticed any difference in the drive, but I've only had it a couple of weeks. There are no other lights on indicating any other problems. Could this be an electrical short somewhere?
Thanks in advance for any input and insight towards this. In the mean time I will continue to scour through the threads in hopes of finding something. It's a great car and I love driving it. It's got 181k on it and I hope to at least double that myself!
02-28-14, 01:01 PM
#2
mdjames, you are correct in that the P0446 is related to your evap 
Starting with a gas cap is the best bet cause it's cheap and easy. If that does not fix it, the diag may be more involved as it could be an open circuit for the vapor pressure sensor, the part itself, vacuum line damage or charcoal canister damage (which all require testing)
The c1233 is related to the YAW sensor (which if this is failing, the ECM will prohibit TRAC & VSC) Are the TRAC and VSC lights on as well? Chances are it's the sensor itself or something in that circuit
The c1256 could be on because of the c1233 coming on. If not, that code could mean brake pressure switch or the brake booster pump motor
I'd hate just throwing parts at it, it may be worth having someone reputable do some testing for you. But just so you know, there was a recall in 1998 for yaw sensor problems. The recall # was 98V080000....may be worth calling Lexus to see if you're car would qualify, because at the time, the dealers would replace the YAW sensor under warranty. Free is always best
-george
Starting with a gas cap is the best bet cause it's cheap and easy. If that does not fix it, the diag may be more involved as it could be an open circuit for the vapor pressure sensor, the part itself, vacuum line damage or charcoal canister damage (which all require testing) The c1233 is related to the YAW sensor (which if this is failing, the ECM will prohibit TRAC & VSC) Are the TRAC and VSC lights on as well? Chances are it's the sensor itself or something in that circuit
The c1256 could be on because of the c1233 coming on. If not, that code could mean brake pressure switch or the brake booster pump motor
I'd hate just throwing parts at it, it may be worth having someone reputable do some testing for you. But just so you know, there was a recall in 1998 for yaw sensor problems. The recall # was 98V080000....may be worth calling Lexus to see if you're car would qualify, because at the time, the dealers would replace the YAW sensor under warranty. Free is always best
-george
02-28-14, 02:43 PM
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mdjames, you are correct in that the P0446 is related to your evap Starting with a gas cap is the best bet cause it's cheap and easy. If that does not fix it, the diag may be more involved as it could be an open circuit for the vapor pressure sensor, the part itself, vacuum line damage or charcoal canister damage (which all require testing)
The c1233 is related to the YAW sensor (which if this is failing, the ECM will prohibit TRAC & VSC) Are the TRAC and VSC lights on as well? Chances are it's the sensor itself or something in that circuit
The c1256 could be on because of the c1233 coming on. If not, that code could mean brake pressure switch or the brake booster pump motor
I'd hate just throwing parts at it, it may be worth having someone reputable do some testing for you. But just so you know, there was a recall in 1998 for yaw sensor problems. The recall # was 98V080000....may be worth calling Lexus to see if you're car would qualify, because at the time, the dealers would replace the YAW sensor under warranty. Free is always best
-george
Starting with a gas cap is the best bet cause it's cheap and easy. If that does not fix it, the diag may be more involved as it could be an open circuit for the vapor pressure sensor, the part itself, vacuum line damage or charcoal canister damage (which all require testing) The c1233 is related to the YAW sensor (which if this is failing, the ECM will prohibit TRAC & VSC) Are the TRAC and VSC lights on as well? Chances are it's the sensor itself or something in that circuit
The c1256 could be on because of the c1233 coming on. If not, that code could mean brake pressure switch or the brake booster pump motor
I'd hate just throwing parts at it, it may be worth having someone reputable do some testing for you. But just so you know, there was a recall in 1998 for yaw sensor problems. The recall # was 98V080000....may be worth calling Lexus to see if you're car would qualify, because at the time, the dealers would replace the YAW sensor under warranty. Free is always best
-george
There are no other lights on...not ABS, VSC or TRAC. Hopefully it's just a short somewhere. I'll have to check to see if the previous owner answered the recall notice.
Thanks again for the input. I'll update again once I've had the CEL checked out again!
03-20-14, 01:23 PM
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Ok well...turns out it was an electrical short from the battery. Apparently someone stuffed a wad of steel wool on the positive battery terminal to try and make a good connection. Found this out after car wouldn't start for a while. Changed out the terminal and everything seems to be fine. No more CEL since. Now back to enjoying this wonderful car!
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