Engine system service required ECM fault

ant33 · Post by **ant33** » 20 Jan 2018, 06:27

Hi,

I am new to forums and this is my first post, so appologies if its in the wrong place. The patient is a 2001 volvo v70 2.4 non turbo 170bhp. The car has come up with the message 'ENGINE SYSTEM SERVICE REQUIRED' and suffered from rough idle. Vida Dice revealed the following codes: ECM-91B7 ECM-9150. This lead me to replace the throttle position sensor in the throttle body to a sacer contactless type.

The vehicle is now idleing fine and appears to be driving ok. However the system service message has remained and so has ECM-91B7. The other code has cleared. Further testing revealed the car battery needed replacing. I have put a new battery in and cleared the codes using vida. However after driving and turning the ignition off and on again, the system service message has reappeared with the code ECM-91B7.

Any help would be much appreciated.

Thanks

Post by **RickHaleParker** » 20 Jan 2018, 09:03

Both codes can be caused by a poorly charged battery or corrosion in the connecting cables, check these first.

Beyond that:

(1) Throttle body not returning to it's mechanical rest position, clean/adjust throttle body mechanics.
(2) One of the two throttle body position sensors is defective.

ant33 · Post by **ant33** » 20 Jan 2018, 10:25

Thanks for your reply. The new battery is providing 12.2V to the throttle socket across pins 5 and 6 when the ignition is on and engine off. The new sacer sensor replaces both of the old sensors so I'm hoping it's not that. I have tested the cable continuity with pins pressed through the wires and all seemed good.

That leaves me with the rest position of the throttle.
I have already cleaned this up. I will take this off and pay closer attention. Do you know if there is any adjustment in this?

Thanks

Post by **RickHaleParker** » 20 Jan 2018, 11:00

Far as I recall that year has no mechanical fine tune. I would look for something hanging up the butterfly valve. Is there any slack in the butterfly?

ant33 · Post by **ant33** » 20 Jan 2018, 11:14

No there is no slack in the butterfly and I have cleaned it up with throttle cleaner. Hmm... I have run out if ideas apart from take it apart again and look again. The new sensor is one of these: https://www.sacer.com.cn/sa300-tps-sensor-volvo.html

ant33 · Post by **ant33** » 20 Jan 2018, 11:22

That link did not eork for some reason. Try this one: https://www.sacer.com.cn/tps-sensor/sa3 ... collateral

Post by **RickHaleParker** » 20 Jan 2018, 13:39

Looks like others here have had problems with the Sacer conversion.

"You measure the voltage across pin 1 & 3 on the Sacer side and compare it to the voltage across pins 4 & 2 on the non- Sacer side with the original sensor reconnected and the black lead hanging loose. "

"Troubleshooting.
If after sensor installation you’ll experience same problems (e.g. limited max RPM, limp mode etc.)
that means, that problem was either not with the original sensor or not only with the original
sensor. Faulty ETM may show same symptoms and error codes related to the sensor (even if the sensor
is fine!). In most cases ETM reload will cure the problem.

If the ETM is damaged – ETM reload and/or new contactless sensor will not help."

Sacer conversion Links:
a) ETM reload https://www.matthewsvolvosite.com/forums ... hp?t=65275
b) Voltage adjustment https://www.matthewsvolvosite.com/forums ... p?p=341961
c) Installation tips https://www.matthewsvolvosite.com/forums ... 12&t=58045
https://www.matthewsvolvosite.com/forums ... hp?t=38504

ant33 · Post by **ant33** » 20 Jan 2018, 14:53

Thanks for your help.
I will look through these posts and try to formulate a plan to tackel this problem. I think more testing of the throttle body is in order.

Post by **RickHaleParker** » 20 Jan 2018, 15:11

At least, you got a second wind now.

ant33 · Post by **ant33** » 21 Jan 2018, 02:24

Looking through the posts, there is some great information. I think I need to match the sensor voltages up by adjusting the magnet. Also mentioned is to clear the ECM. Not sure why, but this is something I did not do. None of these things were mentioned in the sacer instructions.

The car is driving fine at the moment and I have the standard problem of having to keep the car on the road vs having a window of oppertunity to take it off the road to carry out repairs. The wife will have to drive round with the error messege displayed for a bit. I will take a look at this again in the coming weeks and report back on progress.

Thanks again for all the useful information.

Regards