1999 LS 400 - Check VSC and ABS lights on but no codes
07-17-17, 06:08 PM
#1
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1999 LS 400 - Check VSC and ABS lights on but no codes
I have a 1999 LS 400 that has VSC OFF and ABS lights lit plus Check VSC is showing up on the display. I pulled the codes using my Actron AutoScanner Plus (also had OReilly's pull codes using their Bosch code reader (I think the Actron scanner is made by Bosch, as the two appear very similar)). No codes showed up.
<<Scroll to bottom of this post for what ended up being the solution>>
I tried to post this last night and didn't notice that I had tried to include a "tag" that didn't already exist (so it didn't post). Anyway, I received new information since last night: this happened at the beginning of June when my son was driving the car and the code P0121, Throttle/Pedal Position Sensor A Circuit Range/Performance was present. He said the car went into limp mode, he pulled over and shut the car off. He started the vehicle back up and was able to drive home, without issue. He took it to OReilly and they cleared the codes. All indicating lights went away, as did the VSC Off message.
The lights and message reappeared, recently. I performed a search on Club Lexus and found many different scenarios but, none of them fit my problem except one titled, "2003 LS 430 - Check VSC and ABS lights on but no codes". Unfortunately, that thread contained a LINK that is no longer active (or I don't have access to, or whatever - it doesn't work, or I did something wrong). Anyway...
1. I suspect the Throttle Position Sensor (TPS) <<Based upon the new information noted above, this becomes an even higher likelihood>>. However, wouldn't there be a code (like the P0121) if there was a problem with the TPS?
2. The problem could be a wheel sensor but, wouldn't there be a code for the wheel sensor(s) present, if that were the case?
3. I checked the battery with car off and it was 12.43 Vdc. I checked the battery with car running and it was 13.93 Vdc. Based upon this information, I don't believe I have a battery or alternator problem.
The TPS is $509 at OReilly's and $275 at Rock Auto. I don't really want to go that route unless I am quite sure that is the issue. Please advise what are your thoughts.
Thanks in advance!
==================================
The problem ended up being the right rear wheel speed sensor.
Thanks to Yamae, aptoslexus, and everyone else who contributed to this effort!
I suspected (don't ask me why) the wheel speed sensor (I think I may have read it in another post at some point). But, when we checked it, either we mis-diagnosed it or it was intermittently bad (to begin with). Anyway, after trying many things that were suggested as possibilities (replaced battery, replaced TPS, calibrated YAW Sensor (this actually probably was required as a result of the number of times we disconnected the battery during troubleshooting). Finally, just before I was about to give up and replace the ECU, I decided to go back over the possibilities. I checked the wheel speed sensor and found it was open (a.k.a. BAD). I replaced it and haven't had any issues with it, since.
<<Scroll to bottom of this post for what ended up being the solution>>
I tried to post this last night and didn't notice that I had tried to include a "tag" that didn't already exist (so it didn't post). Anyway, I received new information since last night: this happened at the beginning of June when my son was driving the car and the code P0121, Throttle/Pedal Position Sensor A Circuit Range/Performance was present. He said the car went into limp mode, he pulled over and shut the car off. He started the vehicle back up and was able to drive home, without issue. He took it to OReilly and they cleared the codes. All indicating lights went away, as did the VSC Off message.
The lights and message reappeared, recently. I performed a search on Club Lexus and found many different scenarios but, none of them fit my problem except one titled, "2003 LS 430 - Check VSC and ABS lights on but no codes". Unfortunately, that thread contained a LINK that is no longer active (or I don't have access to, or whatever - it doesn't work, or I did something wrong). Anyway...
1. I suspect the Throttle Position Sensor (TPS) <<Based upon the new information noted above, this becomes an even higher likelihood>>. However, wouldn't there be a code (like the P0121) if there was a problem with the TPS?
2. The problem could be a wheel sensor but, wouldn't there be a code for the wheel sensor(s) present, if that were the case?
3. I checked the battery with car off and it was 12.43 Vdc. I checked the battery with car running and it was 13.93 Vdc. Based upon this information, I don't believe I have a battery or alternator problem.
The TPS is $509 at OReilly's and $275 at Rock Auto. I don't really want to go that route unless I am quite sure that is the issue. Please advise what are your thoughts.
Thanks in advance!
==================================
The problem ended up being the right rear wheel speed sensor.
Thanks to Yamae, aptoslexus, and everyone else who contributed to this effort!
I suspected (don't ask me why) the wheel speed sensor (I think I may have read it in another post at some point). But, when we checked it, either we mis-diagnosed it or it was intermittently bad (to begin with). Anyway, after trying many things that were suggested as possibilities (replaced battery, replaced TPS, calibrated YAW Sensor (this actually probably was required as a result of the number of times we disconnected the battery during troubleshooting). Finally, just before I was about to give up and replace the ECU, I decided to go back over the possibilities. I checked the wheel speed sensor and found it was open (a.k.a. BAD). I replaced it and haven't had any issues with it, since.
Last edited by GS4302001; 01-01-18 at 09:01 AM. Reason: Solution to Problem Identified
07-17-17, 10:53 PM
#2
Moderator
Sounds like you are about to have a more serious problem. The voltage glitch from the TPS confuses the ECU and causes your type of problems. You can confirm it observing the voltage swing using an oscilloscope. The genuine TPS alone costs about $100 and it would be better to replace it ASAP before your car stops at a middle of nowhere.
07-18-17, 07:16 PM
#3
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Thread Starter
Thanks for the response Yamae!
OK, I see I have two TPS's, one is for the pedal position (passenger's side) and the other is for the throttle motor position (drivers' side). I found the following thread, "HELP! sensor testing, vsc/vsc off, CEL", which is for a GS 400 which has info about how to check the sensors. There are a couple of different repair manual cuts provided and mine (although not exactly) most closely resembles the first set of instructions. The resistance is the same on both, so as long as the pins are correct, I should be good. I will let you know what I find. The pedal position sensor is the $275 piece and the throttle position sensor is just over $100.
OK, I see I have two TPS's, one is for the pedal position (passenger's side) and the other is for the throttle motor position (drivers' side). I found the following thread, "HELP! sensor testing, vsc/vsc off, CEL", which is for a GS 400 which has info about how to check the sensors. There are a couple of different repair manual cuts provided and mine (although not exactly) most closely resembles the first set of instructions. The resistance is the same on both, so as long as the pins are correct, I should be good. I will let you know what I find. The pedal position sensor is the $275 piece and the throttle position sensor is just over $100.
07-18-17, 09:07 PM
#4
Moderator
Thanks for the response Yamae!
OK, I see I have two TPS's, one is for the pedal position (passenger's side) and the other is for the throttle motor position (drivers' side). I found the following thread, "HELP! sensor testing, vsc/vsc off, CEL", which is for a GS 400 which has info about how to check the sensors. There are a couple of different repair manual cuts provided and mine (although not exactly) most closely resembles the first set of instructions. The resistance is the same on both, so as long as the pins are correct, I should be good. I will let you know what I find. The pedal position sensor is the $275 piece and the throttle position sensor is just over $100.
OK, I see I have two TPS's, one is for the pedal position (passenger's side) and the other is for the throttle motor position (drivers' side). I found the following thread, "HELP! sensor testing, vsc/vsc off, CEL", which is for a GS 400 which has info about how to check the sensors. There are a couple of different repair manual cuts provided and mine (although not exactly) most closely resembles the first set of instructions. The resistance is the same on both, so as long as the pins are correct, I should be good. I will let you know what I find. The pedal position sensor is the $275 piece and the throttle position sensor is just over $100.
The code P0121 is only related to the Throttle Position Sensor. The Accelerator Pedal Position Sensor is related to the codes P1120 and P1121.
So, in your case, you only need to replace the Throttle Position Sensor which costs about $100. It is located behind the throttle motor and it is a bit not easy to access but I'm sure you can do it.
Last edited by Yamae; 07-18-17 at 09:47 PM.
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BNastee (07-07-21)
07-29-17, 03:08 PM
#6
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Thread Starter
Thanks again for the replies. Yes, I thought I was getting a good code reader but...
Anyway, I checked the resistance for the TPS as per the instructions previously noted (i.e. between terminals 1-4) and it was within the range (around 1.73 ohms). I then checked between terminals 1 -3 and 4-3. Those varied from 100 ohms to 1.81kohms, and 420 ohms to 1.8 kohms, respectively. From the normal state, the 4-3 measurement stayed around 1.8 kohms for about 10 degrees of the rotation. I didn't notice any gaps or shorts, though from either. I am using an old Fluke 76, so it may not be sensitive enough to see gaps (or I may be moving it too quickly).
In any case, since I went through the hassle of pulling the TPS off, I'll replace it with one from O-Reilly for roughly $80.
By the way, the car has been working fine other than the indicating lights showing on the dash.
Anyway, I checked the resistance for the TPS as per the instructions previously noted (i.e. between terminals 1-4) and it was within the range (around 1.73 ohms). I then checked between terminals 1 -3 and 4-3. Those varied from 100 ohms to 1.81kohms, and 420 ohms to 1.8 kohms, respectively. From the normal state, the 4-3 measurement stayed around 1.8 kohms for about 10 degrees of the rotation. I didn't notice any gaps or shorts, though from either. I am using an old Fluke 76, so it may not be sensitive enough to see gaps (or I may be moving it too quickly).
In any case, since I went through the hassle of pulling the TPS off, I'll replace it with one from O-Reilly for roughly $80.
By the way, the car has been working fine other than the indicating lights showing on the dash.
07-30-17, 08:55 AM
#7
You might check this
My '99 exhibits similar "VSC messages" about every three years, and I am having that issue again now. Extensive testing has only shown one thing each time: a weak battery. Even if the battery has close to 12.5 volts at no load, and the car starts fine, IF the voltage drops below 10.5 volts while cranking, this model will trigger various VSC messages, and maybe a check engine light. Three years ago I went ahead and replaced the alternator, because of a partially failed rectifier assembly, which produced low charging output, but that's not the case I have now. It seems most batteries barely get through the full warranty period, then go soft. The 2nd gen 400's have an interesting way of letting you know!
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BNastee (07-07-21)
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07-30-17, 12:43 PM
#8
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We will have to check the voltage during starting once we get the new tps installed.
The speedometer and tachometer needles have started to stick quite a bit lately. Did a little digging, this could be a speed sensor problem? Could the VSC indicater lights be related to this issue?
thanks again
The speedometer and tachometer needles have started to stick quite a bit lately. Did a little digging, this could be a speed sensor problem? Could the VSC indicater lights be related to this issue?
thanks again
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BNastee (07-07-21)
08-02-17, 09:47 AM
#10
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Installed new TPS, no real change. Well, now the car doesn't even run, whereas before I mucked with it, it ran fine and just had the VSC and ABS indicators lit. Anyway, when started following resetting the codes, the car sputters then dies. If started a second time, it starts but goes into limp mode. Another thing, we originally installed the TPS incorrectly and got a whole slough of codes. (See below for what remains after the install was corrected)
Based upon input from PureDrifter and fixmiester, we installed a new battery (because the old battery measured 9.6 volts when starting). Again, no real change.
Now it is throwing codes P1125 and P1128, and the VSC and ABS indicators are still lit. P1128 is Throttle Control Motor Lock Malfunction and P1125 is throttle control motor circuit malfunction.
Following the initial install of the TPS, the engine started, but it surged a few times and quit. I tried to adjust the position of the TPS while it was surging on subsequent starts, but never got it before it would quit and require resetting the codes. While I was doing this, my son looked up how to adjust the TPS.
I imagine the P1128 code which is now showing is due to installing the TPS in accordance with a DIY write-up from lexLS.com. I didn't look at the whole "procedure" and just went off of the one picture that he pointed out to me showing to start out the install with the TPS rotated counter-clockwise vs clockwise-as I had originally done. When I saw that, I figured, I must have done it incorrectly and blindly followed how the picture showed. When the engine was started, it went to something like 4000 rpm and he turned it off. It turns out that the "procedure" he found was for a 1990 to 1994 LS400. Ugh, oh well I should have looked at the whole thing before proceeding, but didn't. So, the Throttle Control Motor tried to move and couldn't because the newly installed TPS was all the way bottomed out.
Can the P1128 code be reset, or did this one time incident toast the motor?
Perhaps we blew a fuse - I'll have to check that tomorrow. If there is a specific sequence to reset the P1128 code, please advise.
By the way, since we are seeing the TPS related codes, I am thinking the VSC and ABS lights had NOTHING to do with the TPS circuits, to begin with. Now, I have two different and seemingly unrelated issues to resolve.
Based upon input from PureDrifter and fixmiester, we installed a new battery (because the old battery measured 9.6 volts when starting). Again, no real change.
Now it is throwing codes P1125 and P1128, and the VSC and ABS indicators are still lit. P1128 is Throttle Control Motor Lock Malfunction and P1125 is throttle control motor circuit malfunction.
Following the initial install of the TPS, the engine started, but it surged a few times and quit. I tried to adjust the position of the TPS while it was surging on subsequent starts, but never got it before it would quit and require resetting the codes. While I was doing this, my son looked up how to adjust the TPS.
I imagine the P1128 code which is now showing is due to installing the TPS in accordance with a DIY write-up from lexLS.com. I didn't look at the whole "procedure" and just went off of the one picture that he pointed out to me showing to start out the install with the TPS rotated counter-clockwise vs clockwise-as I had originally done. When I saw that, I figured, I must have done it incorrectly and blindly followed how the picture showed. When the engine was started, it went to something like 4000 rpm and he turned it off. It turns out that the "procedure" he found was for a 1990 to 1994 LS400. Ugh, oh well I should have looked at the whole thing before proceeding, but didn't. So, the Throttle Control Motor tried to move and couldn't because the newly installed TPS was all the way bottomed out.
Can the P1128 code be reset, or did this one time incident toast the motor?
Perhaps we blew a fuse - I'll have to check that tomorrow. If there is a specific sequence to reset the P1128 code, please advise.
By the way, since we are seeing the TPS related codes, I am thinking the VSC and ABS lights had NOTHING to do with the TPS circuits, to begin with. Now, I have two different and seemingly unrelated issues to resolve.
Last edited by GS4302001; 08-02-17 at 07:05 PM.
08-05-17, 09:06 AM
#12
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Set the Throttle Position at 15.3%, after reinstalling the old TPS..
Started and runs as it did before.
Still have the ABS, VSC OFF, and CHECK VSC indicators all still lit.
Started and runs as it did before.
Still have the ABS, VSC OFF, and CHECK VSC indicators all still lit.
08-05-17, 11:01 AM
#13
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Thread Starter
Took trunk apart to access the connector for the right rear wheel speed sensor/brake wear sensor. The wheel speed sensor is fine. The brake wear indicator is toast, but should have no effect on anything.
Should the speedometer work if the car is running, in gear and the rear wheel (s) turning? It wasn't working. Went for drive and speedometer worked. I'm not sure why that would be the case.
Still have the VSC OFF, ABS lights lit and CHECK VSC on the display. Any other suggestions?
Should the speedometer work if the car is running, in gear and the rear wheel (s) turning? It wasn't working. Went for drive and speedometer worked. I'm not sure why that would be the case.
Still have the VSC OFF, ABS lights lit and CHECK VSC on the display. Any other suggestions?
08-07-17, 07:28 PM
#15
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Thanks aptoslexus,
I don't have the SST, so I just jumpered terminals Tc and E1 on the diagnostic connector.
VSC NG and E alternated followed by 36 and 43 alternating.
What do codes 36 and 43 represent? Please advise.
I did the brake pump to reset the Check VSC, but the ABS and VSC OFF indicators were still lit. When I restarted the engine, the Check VSC came right back.
Thanks again!
I don't have the SST, so I just jumpered terminals Tc and E1 on the diagnostic connector.
VSC NG and E alternated followed by 36 and 43 alternating.
What do codes 36 and 43 represent? Please advise.
I did the brake pump to reset the Check VSC, but the ABS and VSC OFF indicators were still lit. When I restarted the engine, the Check VSC came right back.
Thanks again!