Trouble with CEL code and diagnosis
08-05-17, 09:13 PM
#1
Driver School Candidate
Thread Starter
Trouble with CEL code and diagnosis
Hello guys and gals. Id like to start off by thanking you for taking the time to assist me on this matter. I have a 2001 Lexus is300 with a 2jz ge engine. The car has 155xxx miles. I have a CEL code that just wont go away. It says catalyst system efficiency below threshold bank 1 (p0420). The cat is brand new. It has under 6k miles and this cel has been on for about 5k of them. I dont want to start throwing money at and hope i fix the issue. It has a stock exaust. Aftermarket headers. If any of you have any ideas what i can do to test the cat or the O2 sensor id greatly appreciate it.
second set of business. Today i decided tl pull into my local autoparts store and use the code reader to check my CEL codes just to see if any new codes have shown up. Guess what. 1 did. Communication malfunction no.2 (B2798) a little info. The car does not have a keyfob. I use the valet key sensor to shut off the safe mode so i can start the car. I have never had this cel code up untill today. The car does not have any performance issues. No limp mode no rough idle none of that. Im wondering what it could be.
again, thank you for taking your time to help a fellow lexus owner out.
second set of business. Today i decided tl pull into my local autoparts store and use the code reader to check my CEL codes just to see if any new codes have shown up. Guess what. 1 did. Communication malfunction no.2 (B2798) a little info. The car does not have a keyfob. I use the valet key sensor to shut off the safe mode so i can start the car. I have never had this cel code up untill today. The car does not have any performance issues. No limp mode no rough idle none of that. Im wondering what it could be.
again, thank you for taking your time to help a fellow lexus owner out.
08-07-17, 09:06 PM
#2
Hello guys and gals. Id like to start off by thanking you for taking the time to assist me on this matter. I have a 2001 Lexus is300 with a 2jz ge engine. The car has 155xxx miles. I have a CEL code that just wont go away. It says catalyst system efficiency below threshold bank 1 (p0420). The cat is brand new. It has under 6k miles and this cel has been on for about 5k of them. I dont want to start throwing money at and hope i fix the issue. It has a stock exaust. Aftermarket headers. If any of you have any ideas what i can do to test the cat or the O2 sensor id greatly appreciate it.
second set of business. Today i decided tl pull into my local autoparts store and use the code reader to check my CEL codes just to see if any new codes have shown up. Guess what. 1 did. Communication malfunction no.2 (B2798) a little info. The car does not have a keyfob. I use the valet key sensor to shut off the safe mode so i can start the car. I have never had this cel code up untill today. The car does not have any performance issues. No limp mode no rough idle none of that. Im wondering what it could be.
again, thank you for taking your time to help a fellow lexus owner out.
second set of business. Today i decided tl pull into my local autoparts store and use the code reader to check my CEL codes just to see if any new codes have shown up. Guess what. 1 did. Communication malfunction no.2 (B2798) a little info. The car does not have a keyfob. I use the valet key sensor to shut off the safe mode so i can start the car. I have never had this cel code up untill today. The car does not have any performance issues. No limp mode no rough idle none of that. Im wondering what it could be.
again, thank you for taking your time to help a fellow lexus owner out.
B2798 TOYOTA Description This code is stored in the memory when a key that does not have a transponder chip is inserted or if communication between the key and transponder key ECU assy is impossible.
Read more: https://www.autocodes.com/b2798_toyota.html
08-11-17, 10:22 AM
#4
no problem, be prepared for a headache with the 01 ecu and missing keys. Once you've lost both master keys, the ecu can not be reseeded like the 02-05 IS300 ecus (no they are not interchangeable with 01 model year either).
You can program the key fob to operate the keyless entry system, but programming the transponder in the ECU can not be reseeded. Even the SKP900 doesnt have the ability because of the OBDii port doesn't support that function. You'll have to tear into the ECU and locate the transponder chip and use eeprom software to program the hexadecimal keys to a virgin dump file.
If this sounds too complicated, I'd suggest finding a salvage 01 IS300 ecu with at least 1 key fob. This way you can program an additional master key from the original key fob and reprogram your current valet key to the new ecu (it takes about an hr or so to do it).
You can program the key fob to operate the keyless entry system, but programming the transponder in the ECU can not be reseeded. Even the SKP900 doesnt have the ability because of the OBDii port doesn't support that function. You'll have to tear into the ECU and locate the transponder chip and use eeprom software to program the hexadecimal keys to a virgin dump file.
If this sounds too complicated, I'd suggest finding a salvage 01 IS300 ecu with at least 1 key fob. This way you can program an additional master key from the original key fob and reprogram your current valet key to the new ecu (it takes about an hr or so to do it).
08-12-17, 12:20 AM
#5
Driver School Candidate
Thread Starter
no problem, be prepared for a headache with the 01 ecu and missing keys. Once you've lost both master keys, the ecu can not be reseeded like the 02-05 IS300 ecus (no they are not interchangeable with 01 model year either).
You can program the key fob to operate the keyless entry system, but programming the transponder in the ECU can not be reseeded. Even the SKP900 doesnt have the ability because of the OBDii port doesn't support that function. You'll have to tear into the ECU and locate the transponder chip and use eeprom software to program the hexadecimal keys to a virgin dump file.
If this sounds too complicated, I'd suggest finding a salvage 01 IS300 ecu with at least 1 key fob. This way you can program an additional master key from the original key fob and reprogram your current valet key to the new ecu (it takes about an hr or so to do it).
You can program the key fob to operate the keyless entry system, but programming the transponder in the ECU can not be reseeded. Even the SKP900 doesnt have the ability because of the OBDii port doesn't support that function. You'll have to tear into the ECU and locate the transponder chip and use eeprom software to program the hexadecimal keys to a virgin dump file.
If this sounds too complicated, I'd suggest finding a salvage 01 IS300 ecu with at least 1 key fob. This way you can program an additional master key from the original key fob and reprogram your current valet key to the new ecu (it takes about an hr or so to do it).
Thread
Thread Starter
Forum
Replies
Last Post
