Tps Error/fault

[paulr33]

Hi All,

Today I went to start my 33 and once it started the revs bounced to 1600rpm.

Upon pressing the brake pedal the revs would bounce around. I thought this was odd.

I tapped the throttle pedal, revs bounced and the engine check ligh came on.

Upon looking at SENSOR / SW CHECK I noticed TPS went down to 0.02 V in BLACK and then eventually got itself back to 0.33v at idle. Pressing of the throttle pedal would make it go up to aroudn 0.44v and then plummet to 0.02v go BLACK and engine check light come on. I rebooted the car twice and verified I could replicate the problem.

I then turned the car off in concern. I turned the car over to ACC and left it there and watched SENSOR / SW CHECK. It was a consistent 0.33v. I then pushed the pedal slowly to the floor and the volts rose to 3.98v (normal voltage for max). I then took it off and it returned to 0.33v. I thought ok cool its working normally and started the car and all worked fine. No more error light and voltage on the TPS appeared to be normal.

Has anyone else seen this sort of behaviour? My first thoughts lead me to dodgy TPS wiring or the actual sensor being dirty/sticky. It only occurs when cold (I've seen it a few times now). I have only recently resoldered by TPS wiring to splice it into the ABS/ALSD computer so that rules out dodgy wiring spilcing as I made sure it was soldered correctly and electric taped up.

[rob82]

Hi All,

Today I went to start my 33 and once it started the revs bounced to 1600rpm.

Upon pressing the brake pedal the revs would bounce around. I thought this was odd.

I tapped the throttle pedal, revs bounced and the engine check ligh came on.

Upon looking at SENSOR / SW CHECK I noticed TPS went down to 0.02 V in BLACK and then eventually got itself back to 0.33v at idle. Pressing of the throttle pedal would make it go up to aroudn 0.44v and then plummet to 0.02v go BLACK and engine check light come on. I rebooted the car twice and verified I could replicate the problem.

I then turned the car off in concern. I turned the car over to ACC and left it there and watched SENSOR / SW CHECK. It was a consistent 0.33v. I then pushed the pedal slowly to the floor and the volts rose to 3.98v (normal voltage for max). I then took it off and it returned to 0.33v. I thought ok cool its working normally and started the car and all worked fine. No more error light and voltage on the TPS appeared to be normal.

Has anyone else seen this sort of behaviour? My first thoughts lead me to dodgy TPS wiring or the actual sensor being dirty/sticky. It only occurs when cold (I've seen it a few times now). I have only recently resoldered by TPS wiring to splice it into the ABS/ALSD computer so that rules out dodgy wiring spilcing as I made sure it was soldered correctly and electric taped up.

Its because your sharding the TPS signal - different internal impedances wtihin the PFC. I garuntee if you remove the wiring to the ABS/ALSD then it will go back to normal. Its a problem we sometimes encounter at work when you piggyback microtech or autronic ECU's. In these situations we sometimes cant use a TPS and we usually wire in extra ECT and IAT sensor separate to the factory ECU.

[paulr33]

very odd. the problem only occurs when the car is cold. like it never happens when it is warm. and when the problem is present as described above the voltage goes black (out of range or error). the problem has only started occuring since i have spliced it into the abs/alsd loom.

so what other options do i have? can i just ignore it? will i likely see any problems? is there a diode or something i can put in path on the abs/alsd loom to make it a one way signal or something?

[rob82]

very odd. the problem only occurs when the car is cold. like it never happens when it is warm. and when the problem is present as described above the voltage goes black (out of range or error). the problem has only started occuring since i have spliced it into the abs/alsd loom.

so what other options do i have? can i just ignore it? will i likely see any problems? is there a diode or something i can put in path on the abs/alsd loom to make it a one way signal or something?

Its not likely to cause to much issues apart from idle conditions as the PFC wont know when the throttle is closed. The actual TPS still works it just wont know when its at full throttle or closed throttle but it will still pick up transients so your acceleration enrichments will still work. The actual TPS value just floats usually and will never be set therefore the TPS can never calibrate itself to learn close throttle.

Fixes - put the standard ECU back in. Use a separte TPS sensor. From memory the auto's have two TPS's but I think 1 is a closed/open throttle swith so thats probably no good to you anyway however I may be wrong.

Also the condition is usually more easily picked up when cold as there is extra idle steps/dashpot and so forth it will still however happen when hot.

[SKYRYAN]

any more news on this issue?

[paulr33]

havent seen it recently

pops up every month or so

the TPS drops to 0.00 and the engine check light comes on

turning car off mashing the accel pedal a few times and starting the car again clears the issue

i just assumed it was dirt / junk near the sensor somewhere

[White GTS-T]

I thought the tps voltage at idle should be .45v?

[paulr33]

thats correct, it should be

when the issue occurs it drops to 0.00v

[skidkid]

We have just had a similar problem with our S2 stagea. First I bought a brand new tps as fault code and a mechanic said thats what the problem was. Fitted new tps and no different. Went to different mechanic and I was told it is a fault with the ecu that causes tps problem and can't be fixed. Couldn't find a std ecu to replace (rang about two dozen wreckers around aus.) so we are having a Vi-pec ecu board fitted this week.

[skidkid]

What did you find?