ETS light with a one year old Xemodex module

zinman · Post by **zinman** » 25 Jun 2013, 21:34

My 2000 V70 xc has rough idle and goes into limp home mode after weeks of the light going on and off without any noticeable symptoms. I was going to check the brake position sensor before the current symptoms but it seems unlikely that it would cause actual driving issues if it were only the brake position sensor. Am I correct? Also cleaned mass airflow sensor but it looked pristine. Next step seems to be to check for vacuum leaks? No codes related to ETM or MAS came up or misfire codes. I installed a Xemodex throttle body last year and it ran fine up until now. Any suggestions?

Thanks

Post by **precopster** » 25 Jun 2013, 22:39

Your diagnosis is incomplete probably due to what you're scanning with.

Whenever a scan is performed with Vida-Dice system during or after ETS illumination (and pre clearing of codes) there will ALWAYS be a fault code relating either to the throttle body or a related system such as BPS (brake) or APS (accel)

Just because your scanner can't see the code it doesn't mean it isn't there. Unfortunately once you send the clear command the code vanishes "poof" never to be seen again. You can even clear unseen codes with the cheapest solution: Torque (free App) and a ELM327 bluetooth adapter.

Reduced performance will be there when ETS is lit with any of the other sytems as well as the ETM itself so it's back to having the car read properly.

Keep us posted on the outcome

zinman · Post by **zinman** » 26 Jun 2013, 07:36

Thanks, Mike. The codes that I did get were: p1618, p0722, and one related to O2 sensor (upstream). I should also mention that I'm driving without the drive shaft because of propshaft failure if that has any bearing on the output speed sensor circuit, no signal (p0722). With the same scanner, I was able to get a throttle position fault when it was a bad ETM a year ago. Just to be clear, are you saying that the brake position sensor could cause limp home mode? I'll see if I can sputter back to the parts store and get another scan today.

Post by **Matty Moo** » 26 Jun 2013, 08:24

Are you going into transmission limp mode or engine limp mode? Flashing arrow?

zinman · Post by **zinman** » 26 Jun 2013, 09:32

I think I'm in engine limp mode. No tach. reading above 1500; max speed of 25 mph. Doesn't shift above 2nd gear. Also, just got back from parts store. Drove in limp mode with ETS light on. This time one code: p0121 Throttle/Pedal Position Sensor, "A" Circuit, Range/Performance. I'm not surprised, as it is the same behavior as a year ago. I was in denial, because I've not heard of anyone having trouble with the Xemodex module, and no other secondary codes came up to point to another culprit. I felt around for cracks in intake hoses and such and didn't find anything obvious. I did also replace the ABS module last year with a rebuilt/re-soldered unit, so I am familiar with the flashing arrow, vanishing speedometer, TRAC light and other classic symptoms. Worked flawlessly and instantly as did the ETM module--- until now it seems. I'm going to contact Xemodex and see what they say. I will post my results.

Post by **precopster** » 26 Jun 2013, 15:26

I'm surprised it will be the ETM. The P0121 code relates directly to one of the ETM sensor potentiometers but the description is wrong. The Autel EU-702 scanners also read in this format.

Pedal faults begin at P0221 so something is not right here.

Again the scanner may not be giving accurate descriptions though the code may be right or it could be the other way around.

Either way I would probably have it removed and sent to Canada.

zinman · Post by **zinman** » 27 Jun 2013, 18:00

The tech at Xemodex said the ETM is doing what it is supposed to do because the fuse pull test indicated the unit was okay. I did think I fixed the problem because I discovered corrosion on the positive battery terminal. I cleaned it with some baking soda, started the car once, light was still on. Started a second time, all lights gone and power returned that I had not noticed was gone when test driven. I was happy for a day. It started acting up again this evening after running fine today. This time the tach would sometimes go to 3500 or try to shift in passing gear but still misbehaving. I put a voltmeter on the battery and got a reading of 10 volts. I thought that the corrosion probably restricted the voltage enough to make the finer sensors go haywire. I'm guessing at everything of course. I'm an amateur. I guess it wouldn't hurt to put a new battery in and see what happens. As for the codes being goofy, I'll take your word for it. I'm just reporting what the generic scanner reported. The Xemodex man who helped me said I could try another throttle body if it would make me happy but I'd have to pay the shipping. It does have a lifetime warranty. He thinks the engine control unit is a more probable suspect. I don't think it is bad, nor do I want to replace such an expensive part when there are so many things, annoying things, that need attention (air conditioning, rear suspension, stuck door locks, interior hatch panel dangling, sticking shifter button, drive shaft replacement, ...etc. and the car is thirteen years old. I'll try a new battery tomorrow. I'm on my third battery in about six years. The original Volvo battery seemed to last an unusually long time, or maybe the others not so long.

Post by **precopster** » 27 Jun 2013, 20:30

The vehicle requires 12.5 during engine operation (minimum) & over 11V when engine is off to maintain all the modules with correct supply.

What is the voltage a X the battery when engine is running?

Post by **precopster** » 28 Jun 2013, 02:35

Just to clarify the fuse pull test gives you an indication that your electrical system is getting power to the throttle body. It's not a test of the throttle body's reliability. They might as well tell you to turn the ignition ON/OFF and listen for the click of the throttle body starting (same effect)

Neither does it tell you the condition/level of the earth or power supply to the throttle body.

However in this case it is obvious the battery/charging system is the first item to check.

zinman · Post by **zinman** » 28 Jun 2013, 07:36

Well my cheapo analog multi-meter may not be reliable either. My household outlet should give 110v and reads 100; a battery that should be 1.5v reads 1v. My car battery gave a 10v reading off and 11v running.
I'll look for the ETM ground and see if it is covered in oil or has bad contact. Still hoping for a simple solution. I start a new job on Monday. Xemodex said the click after the fuse test meant both potentiometers were working and the whine meant functioning software. I don't speak in clicks and whistles, so I also would think that I know power is flowing to the unit, but nothing more. Thanks.