FYI-for those in the know.
FYI-for those in the know.
Below is for those that work on their own cars either because the car is out of warranty or they do not trust even the Lexus Master Tech. This GS fell in both categories.
Car is friends 1998 GS4 with over 156,000 miles on the clock.
She called me a few weeks ago and told me that the car has a wierd problem. Checked here for some idea of where to look.
When the car was cold the engine would not rev. Only when the car was warmed up did the car run and drive perfectly ,but with the Engine,VSC,VSF OFF lights on. To clear the codes she had to remove the battery terminal. Problem only occurred when the engine was cold. So below is what I did to correct the issue. Hope it will assist someone in the future.
Usually the first thing to come to mind is the Collant Temp Switch. Nope-Removed-heated-cooled-resistance
readings moved as they should.
Checked wiring from CTS to the ECM. Continuity. Fine.
Ok, took out the OBD II scanner. Got a 1121 code. Accelerator Pedal Position Sensor error.
So it could be:
APPS, ECM, or wiring.
First checked the resistance on the Pedal Sensor. Checked good. Checked voltage for the VPA and VPA2 circuits at the ECM-plug 3. Checked good. Checked continuity from Pedal Sensor to ECM. Checked good. Wiggled all of the wires. Still everything checked good.
Put new sensor on car since I bought one ahead of time. My Lexus guy allows me to return even electrical items.
Same problem. HUH???
Pulled code again. 1121. Same thing.
So..I decided to duplicate the problem.
Cooled engine down. Specifically I placed the old Pedal sensor in the fridge to cool to 65 F. Placed item on car and the problem arose it's ugly head. Bingo. onto something. But why did the new Pedal Sensor display the same problem?
Duh? Because I never erased the 1121 code from the ECM. Whenever this code comes up, the ECM turns off the throttle control motor.
So code cleared. New pedal sensor installed and I went ahead and adjusted the TPS up a bit to eliminate the off the line hesitation that Lexus says is normal for the GS. BULLSH!T. She says car runs better than ever. Especially smooth off the line.
Just thought I would share. If you are not familiar with circuits and testing, I suggest your dealer.
Car is friends 1998 GS4 with over 156,000 miles on the clock.
She called me a few weeks ago and told me that the car has a wierd problem. Checked here for some idea of where to look.
When the car was cold the engine would not rev. Only when the car was warmed up did the car run and drive perfectly ,but with the Engine,VSC,VSF OFF lights on. To clear the codes she had to remove the battery terminal. Problem only occurred when the engine was cold. So below is what I did to correct the issue. Hope it will assist someone in the future.
Usually the first thing to come to mind is the Collant Temp Switch. Nope-Removed-heated-cooled-resistance
readings moved as they should.
Checked wiring from CTS to the ECM. Continuity. Fine.
Ok, took out the OBD II scanner. Got a 1121 code. Accelerator Pedal Position Sensor error.
So it could be:
APPS, ECM, or wiring.
First checked the resistance on the Pedal Sensor. Checked good. Checked voltage for the VPA and VPA2 circuits at the ECM-plug 3. Checked good. Checked continuity from Pedal Sensor to ECM. Checked good. Wiggled all of the wires. Still everything checked good.
Put new sensor on car since I bought one ahead of time. My Lexus guy allows me to return even electrical items.
Same problem. HUH???
Pulled code again. 1121. Same thing.
So..I decided to duplicate the problem.
Cooled engine down. Specifically I placed the old Pedal sensor in the fridge to cool to 65 F. Placed item on car and the problem arose it's ugly head. Bingo. onto something. But why did the new Pedal Sensor display the same problem?
Duh? Because I never erased the 1121 code from the ECM. Whenever this code comes up, the ECM turns off the throttle control motor.
So code cleared. New pedal sensor installed and I went ahead and adjusted the TPS up a bit to eliminate the off the line hesitation that Lexus says is normal for the GS. BULLSH!T. She says car runs better than ever. Especially smooth off the line.
Just thought I would share. If you are not familiar with circuits and testing, I suggest your dealer.
Lexus Test Driver
Joined: Dec 2001
Posts: 1,074
Likes: 3
From: New Jersey
Hey Pearl great DIY fix. That was one hell of a service call. She must of been very happy with the outcome.
One question, did she return the favor and service you in return?
One question, did she return the favor and service you in return?
Last edited by DrewGS4; Oct 31, 2004 at 07:42 PM.
Pole Position
Joined: May 2001
Posts: 223
Likes: 0
From: Nevada
Good story, good work on the diag. I hope you did receive just compensation! If you could, let us know how to adjust the TP sensor settings. It's done with a test scanner right? I have a friend at Lexus so let us know! Thanks.
Pole Position
Joined: Apr 2004
Posts: 2,667
Likes: 77
From: FL
Adjusted the TPS up a bit to eliminate the off the line hesitation?
Please explain... Please?
In another thread someone brought up replacing and some percentages... same situation?
https://www.clublexus.com/forums/sho...hreadid=138663
Please explain... Please?
In another thread someone brought up replacing and some percentages... same situation?
https://www.clublexus.com/forums/sho...hreadid=138663
Last edited by CinFulxgs; Nov 2, 2004 at 12:15 PM.
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