96/98 Alternate Service light reset

[ThommyKent]

My annoying service light was on as I replaced my dying battery. After installing the new battery the service light was out. So it seems just a disconnect of the battery will extinguish the light. Not the elegant solution to the problem, but it`s FREE . Of course you need to reset the clock and enter the radio code but the radio does keep the station preselects, so it`s not that bad

[precopster]

Ive disconnected my battery multiple times on my 98 V70R and service light still keeps ticking. Did you chant toward the north wind while reconnecting the battery ?

[phils94850]

I just took the bulb out

[cn90]

Easiest solution: cut a small piece of black electrical tape and place it over the light.
You will never notice the light again.

[misha]

My annoying service light was on as I replaced my dying battery. After installing the new battery the service light was out. So it seems just a disconnect of the battery will extinguish the light. Not the elegant solution to the problem, but it`s FREE . Of course you need to reset the clock and enter the radio code but the radio does keep the station preselects, so it`s not that bad

You are talking about "check engine" light,not about "service" light.

Disconnecting the battery can ONLY reset "check engine" light."Service" light is on untill it's reset with scan tool for models after '95.Service light is on only a few minutes after the car is started,but always on any time you start the car.

[ThommyKent]

Nope, It`s the service light in the lower righthand corner. I think maybe I just got lucky.

[misha]

Does it appear on bulb check,when key is in positon II,along with all other little bulbs?

Is it orange light with "service" message on it?

[esl_97_850_T5]

ThommyKent,

1. There have been a multitude of cases where the '96-'98 850/S70/V70/C70/XC70 SERVICE light does not stay off (ie, remain off during the first 2 minutes after engine start) immediately after the battery is disconnected. This is the first time I've heard of where a battery disconnect did reset the SERVICE light.

Of course, it's well known the battery disconnect resets the CHECK ENGINE light. But, to my knowledge, the battery disconnect has never been reported previously to also reset the SERVICE light in the '96-98 850/S70/V70/etc (in a verifiable and predictably repeatable manner).

It could be that your SERVICE bulb just happened to coincidentally burn out. I think you just got lucky about that.

I also had the SERVICE bulb (apparently) burn out last year in my '97 850 T5. At that time, I had already learned that there is a bit in the response to the ECU 51 (COMBI) A50601 request that accurately reflects when the SERVICE light should be turned on and off. It is bit 3 in the Status byte returned in the E506 response to the A50601 request. This bit gets set/cleared regardless whether the bulb is burned out or not. The same Status byte is also available in the response to the ECU 51 A50701 request (along with a bunch more info). From that bit in ECU 51 A50601 and A50701 and from an examination of the ECU 51 B903, B904, B905, B906, B907, B908, B909, B90A data I could see that the SERVICE light should actually have been on. Hence, I concluded that it had coincidentally burned out.

2. If the response to A50601 is "84 13 51 E5 06 7B 4E", then "Engine is On, SERVICE Light should be On during 2 minutes after engine is turned on (assuming the SERVICE light bulb has not been removed and has not burned out)".

If the response to A50601 is "84 13 51 E5 06 73 46" and if the A50601 request was issued within 2 minutes after the engine is turned on, then "Engine is On, SERVICE Light should be Off during 2 minutes after engine is turned on".

3. You can check the bulb without removing the dash by issuing the A50601 request soon after turning the engine on -- and definitely before the ~2 minute SERVICE bulb illumination timer expires. If the response to A50601 includes the 7B and if your SERVICE light is not illuminating at the time that A50601 was sent, then the SERVICE bulb is very likely burnt out.

If the response to A50601 includes the 73, then repeat a few times to make sure you're actually issuing the A50601 request within 2 minutes of turning the engine on.

4. One way to send the A50601 request is with the latest version of volvo850diag downloadable from volvo850diag.zip You might do something like:

4a. Download volvo850diag.zip, extract, and setup.
4b. Get ELM327 device drivers installed.
4c. Display volvo850diag.html (extracted from volvo850diag.zip).
4d. In volvo850diag, click "Start Realterm".
4e. Turn engine on (and wait about 5-10 seconds).
4f. In volvo850diag, click "My Extra Scans". [That's a quick way to check the SERVICE flag using A50701.]
4g. Turn engine off
4h. In volvo850diag, click "ATZ Setup for ECUs 51/58/01..." and wait for it to finish.
4i. Click ECU 51 "Setup".
4j. Turn engine on (and wait about 5-10 seconds).
4k. Click either ECU 51 "ATSI" or ECU 51 "Read DTCs" (and wait for the Slow Init to finish).
4l. Click ECU 51 "Full Scan".
4m. On Realterm's Capture tab, figure out where the .log file has been created.
4n. Click "Close Realterm".
4o. Copy contents of that .log file into the "Paste..." box of the kwpd3b0_interpreter.html page.

5. Another way to send the ECU 51 (COMBI) A50601 request to monitor whether the SERVICE light should be on or not, even when the bulb is burned out, involves interactively issuing the A50601 request using an ELM327 compatible device and a terminal emulator. The list of ELM327 commands and KWPD3B0 requests, along with additional instructions of when to turn the engine on, involves:

5a. Issue these ELM327 commands:

ATZ
ATL1
ATE1 or ATE0 (depending on your terminal emulator and the ATPP 09 value for your ELM327)
ATI
ATSP 3
ATDP
ATH1
ATAL
ATKW0
ATTA 13
ATRA 13
ATIIA 51
ATWM 82 51 13 A1
ATSH 84 51 13

5b. Turn engine on (and wait about 5-10 seconds).

5c. Issue the following KWPD3B0 request:

A50601

5d. See if the response to A50601 is "84 13 51 E5 06 7B 4E" or "84 13 51 E5 06 73 46" or some other response. The first two responses are explained in item 2 above. Any other response can be interpreted by kwpd3b0_interpreter.html.

6. Also, you could display the B903, B904, B905, B906, B907, B908, B909, and B90A values, all of which are used in determining if the SERVICE light should illuminate. Their values will almost always help in determining if the SERVICE light should be on during the first 2 minutes after engine on.

See elm327_reads_volvo_850_svc70_mileage.html for some details on how the B9xx requests can be used to determine the SERVICE Reminder Intervals' counters and limits and whether one of the limits is exceeded, thereby latching the SERVICE on flag so the SERVICE light will come on during the first 2 minutes.

7. I think the main ways to truly reset the '96-'98 850/S70/V70/etc SERVICE light are:

a. Issue the ECU 51 B030 / B230 request combo, like both volvo850diag and the AST 5408 Volvo SRI Reset Tool do, and (presumably) the DRAPER Reset Tool, Vol-FCR Full, VST (Volvo Scan Tool / Volvo System Tester), or VST equivalents do.

b. Replace the Instrument Cluster with another one that doesn't have any of the ECU 51 B9xx SERVICE Reminder Interval counters exhausting their corresponding limits.

Then there's the ways to "mask" the SERVICE light state:

c. SERVICE bulb burns out (which could happen most anytime during these old cars).

d. SERVICE bulb is removed from the Instrument Cluster (followed by an optional smashing with the feet or a hammer).

e. Covering with black tape an otherwise functioning SERVICE bulb.

esl_97_850_T5

[ThommyKent]

Does it appear on bulb check,when key is in positon II,along with all other little bulbs?

Is it orange light with "service" message on it?

It does test.

[ThommyKent]

ThommyKent,


It could be that your SERVICE bulb just happened to coincidentally burn out. I think you just got lucky about that.

Amazing amount of knowledge. The bulb tests, wish it had burned out!