TCS Code 5-1

[goldNSX]

In a very sharp turn where the TCS has to react the following happened: TCS reacted, cut off the power for about 10 seconds even after on the strait and the yellow TCS light stayed on -> Code 5-1. SM says 'Abnormal fail-safe-relay, throttle actuator or throttle body'
After a restart the yellow light went away and everything seemed to be fine.

Everyone with a hint where to look first?

 

[goldNSX]

I've reset the TCS and got no 5-1 code after a test drive. However the TCS didn't light up at all and I've nearly spun twice. Ok, I don't know what influence the new tires in the front have (205/45 instead of 215/45/16), 255/40/17 in the back.

Time to get the hands filthy. I've runned through the SM (service manual) testing for the TCS (or should I say sado-maso-tests)? Testing the fail-safe-relay is easy as long as you don't happen to test the fuel relay like me (ok, it looks similarly) first. The front and back fuses are ok then. Testing the actator is fine also not bad but I got no inconsistency??? I don't have big hands but fummling with the connectors around the TCS and measuring the voltage is a pain.

After all I've found nothing which leaves two parts open: TCS unit itself and maybe the mechanical part of the actuator. Too good the actuator is not available without the throttlebody, IS THIS TRUE? I won't spend $$$$ for the hole throttlebody.

Further action:
The TCS unit will get new caps. I didn't find any leakages around them but some caps've may tried out.

I know of a second TCS unit to test with and also get another acuator to find out where the problem lies. I still think that the acuator has gone bad as the situation it failed is comprehensible and I used it very much in the past due to soft springs. Normally mechanical things go first.

Any hints greatly appreciated.

 

[jazzmann]

Hi, I'm reusing this old thread b/c it matched my search. If I can come up with an answer to post here, it might actually be helpful then. I'm looking for suggestions on tracking down the source of a '5-1' code being thrown by the TCS computer. I've looked at all the similar TCS threads I can find, including cmc140's Dec. 2015 thread, which turned out to be an improperly adjusted big bore throttle body. I don't think that situation applies here, but it's possible. Here's my situation.

On Monday I took my NSX to the local Acura dealer for state inspection and to get the EGR valve and fuel pressure regulator valve replaced. As soon as I got it back I had a feeling that the engine just didn't feel right. The next day on a long drive out to central PA I got a CEL. At a rest stop I jumped the connector and read the codes. A '1' and a '2' (one short flash, pause, two short flashes, longer pause, repeat) from the ECU and a '5-1' (five long flashes, pause, 1 short flash, longer pause, repeat) from the TCS computer. The ECU codes indicate the front and rear O2 sensors, the TCS code indicates "abnormal failsafe relay, throttle actuator, or throttle body". The "related components" for TCS code 5-1 are those 3 as well as the wire harness and the TCS control unit.

This is similar, but not identical, to a problem I had 2 years ago when a dealer tech accidentally yanked the wire going to the throttle position sensor. In that case the ECU was throwing '7' (throttle angle (position) sensor), '1', and '2', and the TCS computer was throwing '3-7' (throttle angle sensor) and the '5-1' above. What Honcho, myself, and a couple of others were able to figure out was, when the TPS was disconnected, it caused the ECU '7' code and the TCS '3-7' and '5-1' codes. It also threw the PGM-FI into open loop fueling which is on the rich side to keep the engine from running too hot. This caused the abnormally high hydrocarbon reading we got on the emissions test and, after a few hours, fouled O2 sensors and caused the ECU '1' and '2' codes.

I mention this only because the fouling of the O2 sensors seems to be common to both. After about 3 hours of driving on Tuesday, the CEL came on, and checking those codes is what revealed the TCS code as well. So whatever issue is causing the TCS '5-1' code appears to be causing a fueling issue that's fouling the O2 sensors. I can also feel roughness in the engine, especially between 2000 and 2500 RPM, and minor flat spots throughout the RPM range where the engine stumbles or is hesitant to respond to minor throttle changes.

I've found the troubleshooting flow chart for TCS code '5-1' and will start working through it this weekend, but wanted to ask if anyone has any experience with this issue, or has any suggestions for some of the more obvious things to check before going through the whole troubleshooting procedure. Don't even ask why I'm not taking it back to the dealer. Anyone who knows the history of this car knows that dealer techs have done nothing but fuck this car up since Mile High Acura in 2012, including two unsatisfactory experiences at this dealership early on. I only went back because I couldn't get the work scheduled with Ben, and the service manager there has been a friend since he was the tech on the '87 Legend Coupe I bought there 30 years ago this month. For whatever reason, I figured I'd give 'em another chance. Not this time, I'll either figure it out myself or take it to Ben when he's available.

Thanks in advance for any help.

 

[goldNSX]

Interesing that you bring up one of my very old threads. I had code 5-1 only once and that was the only time it occured. A few months ago I've thrown the TCS unit out of the car and won't have any codes from it at all.

All I know is that the TCS unit has around 15 caps in it and as these go bad over time you might have a look into it. I've replaced them some years ago in my recently thrown out unit but didn't find any leaking caps then. But as the TCS unit doesn't get hot as other modules do (like CCU) the caps last longer (but certainly not forever). But there haven't been many reports about TCS unit failures...

I hope that someone else can help you.

 

[jazzmann]

Interesing that you bring up one of my very old threads. I had code 5-1 only once and that was the only time it occured. A few months ago I've thrown the TCS unit out of the car and won't have any codes from it at all.

All I know is that the TCS unit has around 15 caps in it and as these go bad over time you might have a look into it. I've replaced them some years ago in my recently thrown out unit but didn't find any leaking caps then. But as the TCS unit doesn't get hot as other modules do (like CCU) the caps last longer (but certainly not forever). But there haven't been many reports about TCS unit failures...

I hope that someone else can help you.

Yeah, it came up high on the list of search results and matched my topic so I used it instead of creating a new one. My guess is that it will be something simple and obvious like a harness connector not reattached. It was fine before the tech fiddled around in there to replace the EGR valve. That's what I plan to do first - check all the connectors referenced in the flow chart. If they're all attached, then I'll get into the details checking the pins for connectivity per the chart.

One thing I've never understood about getting rid of the TCS unit - it seems to handle other stuff beyond just the traction control duties. For example, the 3-7 code it threw when the TPS was unplugged, and this 5-1 which has to do with the throttle actuator. What happens to those functions when you toss the TCS unit?

 

[goldNSX]

You can try to unplug all connectors from the TCS and see what happens.

See here: http://www.nsxcb.co.uk/showthread.php?14032-TCS-module-differences
and the explanations of the NSX-guru Kaz.

 

[Honcho]

Will-

I think I've mentioned it before, but you probably want to scrap the TCS unit anyway. I only kept it because I drove the car in the snow. If you really want to make a project of it, you could pull it and send to Kaz for inspection/testing, but honestly even Kaz got rid of his own TCS long time ago. He calls it "ancient." Might be interesting, as Gold mentions, to take it out of the loop entirely and see what the ECU tells you re the throttle angle sensor. If the throttle angle sensor is the culprit, it might be masked by the TCS error code. It is also possible the TCS error is throwing the ECU into open loop independent of the ECU. Page 11-50 of the service manual covers troubleshooting the throttle angle sensor, and I think you might want to try isolating that sensor. It should tell you if the TCS is the problem or the sensor.

 

[Fabunoz]

Hi, I'm reusing this old thread b/c it matched my search. If I can come up with an answer to post here, it might actually be helpful then. I'm looking for suggestions on tracking down the source of a '5-1' code being thrown by the TCS computer. I've looked at all the similar TCS threads I can find, including cmc140's Dec. 2015 thread, which turned out to be an improperly adjusted big bore throttle body. I don't think that situation applies here, but it's possible. Here's my situation.

On Monday I took my NSX to the local Acura dealer for state inspection and to get the EGR valve and fuel pressure regulator valve replaced. As soon as I got it back I had a feeling that the engine just didn't feel right. The next day on a long drive out to central PA I got a CEL. At a rest stop I jumped the connector and read the codes. A '1' and a '2' (one short flash, pause, two short flashes, longer pause, repeat) from the ECU and a '5-1' (five long flashes, pause, 1 short flash, longer pause, repeat) from the TCS computer. The ECU codes indicate the front and rear O2 sensors, the TCS code indicates "abnormal failsafe relay, throttle actuator, or throttle body". The "related components" for TCS code 5-1 are those 3 as well as the wire harness and the TCS control unit.

This is similar, but not identical, to a problem I had 2 years ago when a dealer tech accidentally yanked the wire going to the throttle position sensor. In that case the ECU was throwing '7' (throttle angle (position) sensor), '1', and '2', and the TCS computer was throwing '3-7' (throttle angle sensor) and the '5-1' above. What Honcho, myself, and a couple of others were able to figure out was, when the TPS was disconnected, it caused the ECU '7' code and the TCS '3-7' and '5-1' codes. It also threw the PGM-FI into open loop fueling which is on the rich side to keep the engine from running too hot. This caused the abnormally high hydrocarbon reading we got on the emissions test and, after a few hours, fouled O2 sensors and caused the ECU '1' and '2' codes.

I mention this only because the fouling of the O2 sensors seems to be common to both. After about 3 hours of driving on Tuesday, the CEL came on, and checking those codes is what revealed the TCS code as well. So whatever issue is causing the TCS '5-1' code appears to be causing a fueling issue that's fouling the O2 sensors. I can also feel roughness in the engine, especially between 2000 and 2500 RPM, and minor flat spots throughout the RPM range where the engine stumbles or is hesitant to respond to minor throttle changes.

I've found the troubleshooting flow chart for TCS code '5-1' and will start working through it this weekend, but wanted to ask if anyone has any experience with this issue, or has any suggestions for some of the more obvious things to check before going through the whole troubleshooting procedure. Don't even ask why I'm not taking it back to the dealer. Anyone who knows the history of this car knows that dealer techs have done nothing but fuck this car up since Mile High Acura in 2012, including two unsatisfactory experiences at this dealership early on. I only went back because I couldn't get the work scheduled with Ben, and the service manager there has been a friend since he was the tech on the '87 Legend Coupe I bought there 30 years ago this month. For whatever reason, I figured I'd give 'em another chance. Not this time, I'll either figure it out myself or take it to Ben when he's available.

Thanks in advance for any help.

I’m having same exact issues with my 1992 where the 1,2,7 CEL went on and tcs 37 51as well.I thought it was only the o2 sensors but might be a bigger issue.what did you do to fix the issue?Did you have to do the tps sensor DIY or did you simply just replug the connector that the tech yanked?maybe I will clean that sensor/connector harness see if it works.wondering if could be any other items as well read that 51 could be main relay on another post.don’t want to buy another throttle body if possible .let me know what you did to resolve the issue thanks!or if anyone else has suggestions help would be appreciated

 

[jazzmann]

The original TCS issue back in 2015 that I referred to (same as yours) was solved by plugging the TPS connector back in. The CEL 7 is a pretty strong indicator that there's a problem with the connection between the TPS (throttle angle sensor in the FSM) and the ECU. Plugging the connector back in made everything go away except CEL 1 & 2 and once I drove it a while and the carbon burned off of the O2 sensors, they went away too.

The issue in 2017 that prompted this post, I got a CEL light the day after a service and investigating that revealed CEL 1 & 2, minus the 7, and TCS 51, minus the 37. The 51 indicates some kind of problem with throttle-related hardware and possibly related components, including the TCS control unit. Ultimately I took the advice of everyone here and unplugged the TCS control unit. I can't say for certain whether that fixed the issue. The issue may have been resolved independently because I remember having it in for service with Ben around that time... actually, yes, that's when Ben did a full fuel system refresh, including dropping the tank and cleaning it out. We decided to just nuke the issue and start fresh from the tank to the injectors. The problem went away. Then sometime after that I unplugged the TCS just because. I've been running without it since.