Check Eng Light Egr

[914lps]

My check eng light on my 91 LS 400 has been going on and off. ODB 1 so it will not hold a code. When down to about 2 gal of gas light comes on. Fill up, light goes off... Until today. It finailly stayed on. Had it read. Got an EGR messadge. So what am I most likly in for?

[flanker271]

Four possibilities:

1. EGR modulator is bad

2. Vacuum modulator is bad

3. Vacuum line is leaking

4. EGR valve is bad

My LS is being serviced at my local toyota dealer as I type for the same reason: EGR modulator needed replacement.

[Shadow]

ODB1 does hold codes.

[914lps]

ODB1 does hold codes.

Sorry Lexus told me it did not... Gee a dealer not knowing what they are saying........ :whistles:

[sha4000]

ODB1 does hold codes.

Sorry Lexus told me it did not... Gee a dealer not knowing what they are saying........:whistles:

it just doesnt hold codes with the car off, when your CEL comes on while you are driving the difference is that if your car is obd1 when you turn the car off you lose the code until you restart the vehicle and you have to wait until the CEL comes back on but with obd2 vehicles the computer retains te code information

[Shadow]

it just doesnt hold codes with the car off, when your CEL comes on while you are driving the difference is that if your car is obd1 when you turn the car off you lose the code until you restart the vehicle and you have to wait until the CEL comes back on but with obd2 vehicles the computer retains te code information

My 1st gen LS with ODBI DOES retain engine codes even with the engine off. That is why one has to remove power to the ECU to clear recent codes from memory. Also, the ECU is programmed to purge old codes if it doesn't see the same codes again for a certain number of engine on-off cycles.

Go ahead and pull the codes if CEL came on recently.

[mann777]

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Hi i was one of the victims of the dread warning "engine checklite" I carried the following intstruction as per manual .The ECU contains a built in self diagnosis system by which troubles the engine signal network are detected and the checklite warning come up.The light goes off automatic once the malfuntion has been repaired. The diagnostic codes remain in the ECU memory until it is cleared by removing the EFI fuse with the ignition switch off. The diagnostic codes can be read by the number of blinks of the "check: engine warning light .Using the TE1 and E1 terminals on the TDCL located below at the driver side or check connector are connected using the check connector tool. Part no#SST 09843-18020. The lowest code appears first A lot of procedure goes into this with regards to the blink pattern.. I suggest u just have the fuse EFI removed and connected back.( removed for 20 - 30 seconds) . Once completed now remove trhe battery terminals ( - negative terminal only) and refit them after 5 minutes so that to erase from the memory itself. Have a test drive. it should not come up, if it is then the procedure followed is not done correctly. If anybody is interested i can send the whole diagnostic procedure by email. mail me on mann68@gmail.com. I would be happy to assist the members.

[Leadfoot]

[

Using the TE1 and E1 terminals on the TDCL located below at the driver side or check connector are connected using the check connector tool. Part no#SST 09843-18020.

I have a question about the service tool above, is it just a shorting wire or does it have a specific resistance?

I am keen to check my timing and have not wanted to test it by shorting out these terminals in case it damages it.

Thanks,

Leadfoot.

[mann777]

Marcus I have sent u the attached pdf file, it should solve your clarifications. for other members as well the attached file is in pfg format, version 6. please help yourself to study the diagnosis of this defect. :)

Checklight__procedure.pdf

[ftmail]

Marcus I have sent u the attached pdf file, it should solve your clarifications. for other members as well the attached file is in pfg format, version 6. please help yourself to study the diagnosis of this defect. :)

It is not clear to me from the pdf file if the SST 09843-18020 is just a shorting wire or if it has a specific resistance ? This tool is mentioned in other test I need to perform, but do not have the tool...

[leximus]

You can use a wire or paper clip (small one that doesn't have a plastic colored coating). I used both, but prefer the wire.

I too have the dreaded CEL (Check Engine Light) along with the "TRAC/OFF" light. I traced the code to a Check Engine code of 71 (EGR Malfunction) and then tested the "TRAC/OFF" code (by placing the wire into the E1 and Tc holes as the manual suggests) and it came back with code 13 (Open in TRAC throttle relay circuit) and code 51 (problem in Engine Control System - which I think is the EGR gas temp. sensor circuit).

Overall, although I would love to fix the issues, I need some help. Can anyone provide additional insight?

Thanks!