LED code reader/ECC help

[misha]

Last year 850s with M4.4 still use flash codes for ECC ONLY.
Everything is fully OBD II except ECC.
So...flash code reader will work on ECC.
S,v70 from '97 (transitional year from 850 to S,V70)got fully OBDII ECC and Volvo Scan tool is required for diagnostics.

[RickHaleParker]

I know on the 960/S90/V90 with 4.3, 4.4, the ECC has a built in flash code reader for the ECC only.

Has anybody ever tried this on the 850 ECC?

SELF-DIAGNOSTIC SYSTEM

The EEC system incorporates a self-diagnostic function that indicates system faults through a series of trouble codes. The presence of fault(s) is indicated by flashing A/C OFF button. The control panel is programmed to enter a pre-programmed mode when a fault is detected. Under fault condition, control panel ignores the faulty signal, selects an alternative pre-programmed value and prevents delivery of faulty output signals.

Entering Self-Diagnostics

To enter mode, ensure engine is running. Shine a non-fluorescent, bright light on solar sensor. Place blower fan control knob in AUT position and function selector knob in vent position.

1. Place temperature control knob to maximum cooling (pointing straight down).
2. Ensure recirculated air switch is depressed and A/C OFF button is released.
3. Depress and release A/C OFF button within 5 seconds to start self-diagnostic mode.

Each fault code consists of 3 digits. For example, Code132 is displayed by a single flash of the A/C OFF button for the first digit (number 1). After a pause, the second digit of code (number 3) is indicated by 3 flashes. After another pause, the third digit of code (number 2) is indicated by 2 flashes. See TROUBLE CODE IDENTIFICATION table.

Three different fault codes may be stored in memory. However, only one code may be displayed upon request. It may be necessary to request display of fault codes a number of times to ensure all fault codes are displayed.

Exiting Self-Diagnostics & Clearing Codes

To exit self-diagnostics, turn ignition off. All codes are cleared when ignition is turned off. Fault codes are not stored in memory. Even if a code has occurred several times during a period of time, code will only be stored until ignition is turned off.

[Peevarino]

That sounds interesting, but where’s the solar sensor?

[RickHaleParker]

That sounds interesting, but where’s the solar sensor?

The solar sensor, combined with the theft alarm diode, is a photodiode which generates a current when exposed to solar radiation. In other words the blinking led on the top of the dash.

A led can be use as a light source or a light detector. When the anti-theif is armed it is used as a light. When the anti-theif is disarmed, it is used as a light detector.

This is how the Driver Information Module (DIM) knows when to automatically dim the dash lights.

[Peevarino]

I’ll give it a go when I get to work today

[abscate]

Doesn't this same sensor also serve as an input into ECC for solar heat load?

I didn't know they dual purposed the LED - thats clever.

[misha]

No...no LED.
There is LED and solar sensor on that piece of plastic.
Led for Volvo Guard II on the top of it and solar sensor for ECC aside.
It's NOT for dimming the dash lights...at least on 850.
I have it...bought the car almost brand new and don't have that feature.

[RickHaleParker]

Doesn't this same sensor also serve as an input into ECC for solar heat load?

I didn't know they dual purposed the LED - thats clever.

"In direct sunlight, the temperature control dampers are positioned to provide a lower temperature, as determined by solar
sensor input. If the engine is cold and outside temperature is low, the temperature control dampers are set for more heat to reach the
desired temperature faster."

LEDs have been used to build Poorman's Pyranometers.