No code, but "TCS OFF" light won't go out
mines like that too.. but when I first start the car or just turn the key to on, I can turn it on and off but after the car is started for about 10 seconds it goes off. Where can I start tracing the problem down at.. ive checked all fuses and there all fine.
Teching In
Joined: Nov 2006
Posts: 36
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From: Milwaukee, WI
my 98 also has the TCS off all the time and all fuses check out. I replaced the dash switch but no luck. The dealer said it might be a bad wheel speed sensor. I was told a smart OBD2 scanner would pick it up.
Thread Starter
TECH Veteran
Joined: Dec 2001
Posts: 4,117
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From: Ft. Lauderdale, FL, USA
Here's what fixed it.
It appears that when your TPS (Throttle Position Sensor) goes out it will affect the IAC, TCS and it will make the PCM go to a Speed Density Tune. In some cases you will get "NO" SES light. I never had one show up at all ever. I replaced the IAC and it did nothing. My friend scanned it this weekend and it did show the TPS was not working, or whatever the computer says, I wasn't looking at it. I replaced the the TPS today ($36.95 at Advance Auto) and the engine and everything else is perfect again.
When the PCM goes to Speed Density Tune you can unplug the TPS and the car will still run just fine. The only thing that sucks is cold start, it will idle erratically and you MUST pedal the throttle for the first minute or so to keep it running until it warms up, than it will idle by itslef. Also, sometimes when you come to a stop at a light or stop sign it will surge up and down.
.
It appears that when your TPS (Throttle Position Sensor) goes out it will affect the IAC, TCS and it will make the PCM go to a Speed Density Tune. In some cases you will get "NO" SES light. I never had one show up at all ever. I replaced the IAC and it did nothing. My friend scanned it this weekend and it did show the TPS was not working, or whatever the computer says, I wasn't looking at it. I replaced the the TPS today ($36.95 at Advance Auto) and the engine and everything else is perfect again.
When the PCM goes to Speed Density Tune you can unplug the TPS and the car will still run just fine. The only thing that sucks is cold start, it will idle erratically and you MUST pedal the throttle for the first minute or so to keep it running until it warms up, than it will idle by itslef. Also, sometimes when you come to a stop at a light or stop sign it will surge up and down.
.
problem solved. these problems i was having was ALL because i rewired my map sensor wire harness wrong after i ripped it out on accident trying to take the intake out the 3rd ******* time It is confirmed, a messed up map sensor wire will set off a tps code.
Do a search for P0121. I fought this for a long time before I discovered the answer.
Yes, you are absolutely correct, the poor driving manners are from switching into SD mode when the P0121 code gets thrown. The PCM thinks the tps sensor is whacked because there's more air than it's expecting at a given throttle position.
I replaced the sensor a couple of times before I figured out that if it's not the TPS sensor it's the tune.
P0121 has a MAP window, frequently mods that increase airflow (cams, intakes, heads, etc) will throw the map values outside that window and cause the P0121 code to be thrown.
The easiest way to fix the problem is to open up the MAP threshold on the P0121 code. This will keep the code from being thrown and popping you into SD mode where the drivability issues occur.
Hope this helps.
Rob (Bad30th)
Yes, you are absolutely correct, the poor driving manners are from switching into SD mode when the P0121 code gets thrown. The PCM thinks the tps sensor is whacked because there's more air than it's expecting at a given throttle position.
I replaced the sensor a couple of times before I figured out that if it's not the TPS sensor it's the tune.
P0121 has a MAP window, frequently mods that increase airflow (cams, intakes, heads, etc) will throw the map values outside that window and cause the P0121 code to be thrown.
The easiest way to fix the problem is to open up the MAP threshold on the P0121 code. This will keep the code from being thrown and popping you into SD mode where the drivability issues occur.
Hope this helps.
Rob (Bad30th)
Originally Posted by senicalj4579
problem solved. these problems i was having was ALL because i rewired my map sensor wire harness wrong after i ripped it out on accident trying to take the intake out the 3rd ******* time It is confirmed, a messed up map sensor wire will set off a tps code.
Rob (Bad30th)
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Originally Posted by Bad30th
Glad to hear you double-checked your wiring and found the problem.
Rob (Bad30th)
Rob (Bad30th)
Double checked?
I reinstalled the damn intake 3 different times. I'm a ******* pro now I never would have thought that a map sensor wire could make your idle messed up,disable your traction control,make your trans shift so damn hard you think its gonna snap every time,and all at the same time it throws a friggin throtle position sensor code..go figure Thanks for all the info bro. I'm really happy this problem is all over.....I HOPE
Last edited by senicalj4579; Apr 4, 2007 at 01:09 PM.
I also have the TCS OFF light problem. It comes on as soon as I put the key to the ON position, and when I hit the switch nothing happens. My ABS works fine. I have also scanned the car for trouble codes and nothing came up. I have checked the sensors in the rear wheels and they are conncted. The fuse is also good.
the car has no other problems, it idles good and does fine on a cold start. and there is no SES light.
The car had this problem when I bought it. I think it might have to do with the dealer cleaning the engine compartment with chemicals.
the car has no other problems, it idles good and does fine on a cold start. and there is no SES light.
The car had this problem when I bought it. I think it might have to do with the dealer cleaning the engine compartment with chemicals.
I had this happen 2 different times on my car and it ended up being because I had gotten the car dynoed and one of the straps pulled the electrical connector. It is on the drivers side of the car just forward and above the rear axle.
this one is between the drivers side rear tire and the center of the rear axle. It is just forward of the axle, mounted on the bottom of the car. Pretty much right where the drivers side backseat passenger's butt would be except on the bottom of the car.
TECH Resident
Joined: Oct 2005
Posts: 781
Likes: 0
From: Taxme, Ohio
I had the same thing with the TCS OFF but I have one of those modules that reverses the function of the switch. However I had my manifold off and was 99% positive the weatherpack and two vacuum lines were in place before bolting it all down. It turns out the connector and one vacuum line was disconnected, probably from wrestling with the vacuum line to the power brake booster. After righting those things the TCS light now works with the button. BTW, if the electrical connector is off or a wire is broken you should get a SES light with a DTC P0107 (MAP sensor low voltage = vacuum high).
Mine did the same thing, TCS light would go on and off after cam install. I checked all my fuses, and then I had a code for the MAP. I took it off the intake to find it covered with oil... I cleaned it, re-installed and then checked the braking system on the rear of the car. To my surprise, the passenger rear caliper bracket bolt was so loose I could finger tighten it back down! I took the big socket wrench out and fixed that issue. If it wasn’t for the TCS light operating on and off, who knows how long I would have driven it like that or how much damage could have resulted. I have since fixed all those problems and no light as of yet.
Just some things to look for.
Just some things to look for.
So I am getting the same TCS off light issue with no light or function on the switch ever and the P0107 Map pressure low. Should I start out checking the MAP sensor or what? I also have the CO240 TCS not allowed? PS I just bought the car 2 weeks ago so how could I know if it was tuned out?
TECH Resident
Joined: Oct 2005
Posts: 781
Likes: 0
From: Taxme, Ohio
P0107 is not MAP pressure low. It is MAP voltage low which means the pressure is pegged high. If there is no connection or the sensor has failed to communicate with the computer OR vacuum is totally high then P0107 is thrown. Check your connection first.
here is a copy of a post i made on another board about this issue
I have had an issue with my TCS for some time it would randomly turn itself off and then back on at an unopertune time. Over on CR most of you know Brian has been posting about his Phantom TCS issue. Brian showed me a link to an old post where they talked about the P0121 map code causing trouble.
Well That didnt sound right because I havent seen that code but it got me thinking about the code i do through all the time P0106 map. So went into engine diagnostics/ airflow/ mapsensor and found two tables that are the values for the high and low P0106 map. I lowered the values in the low table to 40% and NO MORE TCS LIGHT FLOATING ON AND OFF. I only lowered it 20% the first time and watched the TCS go off when the code threw so i lowered it to 40% and that was the end of it. I may take it down even further but this appears to be a geniune fix not a mask over that still allows the tcs to float in and out. Thought I would share the wealth
I have had an issue with my TCS for some time it would randomly turn itself off and then back on at an unopertune time. Over on CR most of you know Brian has been posting about his Phantom TCS issue. Brian showed me a link to an old post where they talked about the P0121 map code causing trouble.
Well That didnt sound right because I havent seen that code but it got me thinking about the code i do through all the time P0106 map. So went into engine diagnostics/ airflow/ mapsensor and found two tables that are the values for the high and low P0106 map. I lowered the values in the low table to 40% and NO MORE TCS LIGHT FLOATING ON AND OFF. I only lowered it 20% the first time and watched the TCS go off when the code threw so i lowered it to 40% and that was the end of it. I may take it down even further but this appears to be a geniune fix not a mask over that still allows the tcs to float in and out. Thought I would share the wealth
TECH Resident
Joined: Oct 2005
Posts: 781
Likes: 0
From: Taxme, Ohio
If your engine WASN'T heavily modified and you were tripping the p0106 (MAP sensor performance unexpected) then I wouldn't think changing the threshold to be the right thing to do. But for you it is obviously good. For the rest of us; there's a need to sort out the map sensor or its wiring. It is apparent to me that the MAP sensor data is joined at the hip to the TCS / ASR.
Originally Posted by Quickin
Here's what fixed it.
It appears that when your TPS (Throttle Position Sensor) goes out it will affect the IAC, TCS and it will make the PCM go to a Speed Density Tune. In some cases you will get "NO" SES light. I never had one show up at all ever. I replaced the IAC and it did nothing. My friend scanned it this weekend and it did show the TPS was not working, or whatever the computer says, I wasn't looking at it. I replaced the the TPS today ($36.95 at Advance Auto) and the engine and everything else is perfect again.
When the PCM goes to Speed Density Tune you can unplug the TPS and the car will still run just fine. The only thing that sucks is cold start, it will idle erratically and you MUST pedal the throttle for the first minute or so to keep it running until it warms up, than it will idle by itslef. Also, sometimes when you come to a stop at a light or stop sign it will surge up and down.
I guess I should log it and find out whats going on with my TPS.
.
It appears that when your TPS (Throttle Position Sensor) goes out it will affect the IAC, TCS and it will make the PCM go to a Speed Density Tune. In some cases you will get "NO" SES light. I never had one show up at all ever. I replaced the IAC and it did nothing. My friend scanned it this weekend and it did show the TPS was not working, or whatever the computer says, I wasn't looking at it. I replaced the the TPS today ($36.95 at Advance Auto) and the engine and everything else is perfect again.
When the PCM goes to Speed Density Tune you can unplug the TPS and the car will still run just fine. The only thing that sucks is cold start, it will idle erratically and you MUST pedal the throttle for the first minute or so to keep it running until it warms up, than it will idle by itslef. Also, sometimes when you come to a stop at a light or stop sign it will surge up and down.
I guess I should log it and find out whats going on with my TPS.
.
EDIT- I logged mine and it seemed to be fine. My tps and maf seemed to be inline with what I expected. 6 gm/s at idle. Got it to about 212 gm/s at 5500rpms. TPS was consistent with where ever my foot was.
Am I correct in assuming that the TPS is not my issue?
Also my car doesn't surge at all like stated. It does idle a little funny at start up on a cold morning for a few seconds. Rev it up a couple times and it's fine. By cold I mean below freezing, about 10-30* f. Any colder than that and I have a hard time going outside haha.
Last edited by PICNIC_GEORGE; Jun 16, 2007 at 02:03 PM.