1996 850 T5 Intermittent CEL, no codes

[Sommerfeldt]

So, here's a fun one... I've still got my intermittent CEL/lambda light coming on every now and then. The car doesn't set any codes, and the CEL goes away after a while. After having this happen quite a few times now, I've at least got some interesting situational data. If anyone knows how to look for a cause for this, I'm all ears.

- CEL comes on;
a) either when braking or
b) when flashing high beams or
c) a combination

But, it only happens now and then, not at all every time I brake or flash my lights. But, when it happens, it's always alongside one of those.

- CEL goes off;
a) either when waiting long enough (~50 miles) or
b) waiting a shorter distance, and changing between ECO and Sport modes

It apparently doesn't affect the car at all... it's just a PITA to have it happen.
So...what to do?

- S

[esl_97_850_T5]

Sommerfeldt,

After reviewing a couple of your prior threads and reviewing some PMs, I've got some questions.

- How are you attempting to read the codes?

- Are you still using the ELM327 WiFi dongle with DashCommand, Shift (whatever that is), and EOBD Facile?
- If yes, which platform for DashCommand -- Windows, Android, or what?
- Also, which platform for EOBD Facile -- Windows, Android, Mac, iPhone/iPad?
- Also, have you tried any other software since 2015-04?

- Do you have any other purportedly ELM327-compatible devices?

- Did you ever get the push-button flashing LED tool operational?
- Or did you get some other more generalized iteration of it operational that can switch between different OBDII port pins?
- If flashing LED tool is operational, does it respond with the 1-1-1 code always when you are pressing the button for OBDII pin 3 to talk to Motronic 4.3?
- Has a flashing LED tool been used to read codes for ECC (if you have an Electronic Climate Control)?

- Do you have a VAG/COM KKL cable?
- Have you used it with any version of Vol-FCR? If so, what ECUs could connect? And what codes were read/cleared, if any?
- Have you used it with Brick-Diag Free v0.0.6.6? Same questions -- what ECUS could connect and what DTCs were read/cleared?

- Do you have any handheld OBDII scanners?

- Do you have an Android device which could be used for car diagnostics (once capable software was downloaded to it)?

- Have you tried concocting a Hannspree / Adafruit homebrew?

- Have you ever tried volvo850diag with any purportedly ELM327-compatible device?
- Have you ever submitted any volvo850diag log / OBDwiz or TouchScan log / or other ELM327 style data to kwpd3b0_interpreter.html?

And, most importantly, since this is being edited after abscate's suggestion to check the grounds, have you followed abscate's advice?

esl_97_850_T5

[abscate]

Definitely check your engine grounds by removing and cleaning

[Sommerfeldt]

Definitely check your engine grounds by removing and cleaning

That's a damn good idea. I should have thought of that. Thanks.

esl; I've used all the tools in my arsenal - blinky thingy, which seems to work, and I also took it down to the local Bilia, which is the Volvo dealership over here. Nothing.

The elm327 is pretty much a bust - I can still get it to talk to the tranny, but other than that, it's not much use. I'm using it with iOS, and a pile of different apps. My Hannspree idea is on hold, since both cost and general complexity skyrocketed.

I'll try abscate's words of wisdom tomorrow if the weather holds up.

- S