OBD II Data Link Connector - Checking Procedures
SECTION2
GROUP
28
NO.
811
DATE
April 1994
Checking OBD II data link connector (DLC) 850 Turbo M/Y1994-->
REFERENCE: TP 2301201; 08/93; Motronic 4.3 SFI/DI engine management system.
CHECKING OBD II DATA LINK CONNECTOR (DLC)
The operation of the OBD II data link connector (DLC) should be checked if there is reason to suspect that the connector may not be working.
The OBD II diagnostic system, installation of which is legally compulsory, enables the technician to plug in a Generic Scan Tool (GST) to obtain a readout of diagnostic trouble codes (DTCs) and parameters. OBD II incorporates DTCs and parameters relating to exhaust emission components.
The references contained in this bulletin are to Service Manual, Section 2(23, 28) Motronic 4.3 SFI/DI engine management system, 850 1994- (TP2301201). The references are given in square brackets (e.g. [LA3]).
Remove coin holder.
Release OBD II DLC.
Multimeter measurements are made at the rear of the component
- Access backside of OBD II DLC by removing front box of center console. Front box is attached to center console by 2 screws
Note:
Before starting checking procedure, make sure all doors are locked and courtesy light is out, thus avoiding ground potentials.
A1
CHECKING POWER GROUND LEAD
- Switch off ignition.
Important:
Wait go seconds (allows ground potential to stabilize).
- Connect ohmmeter between OBD II DLC terminal 4 and cigarette lighter ground.
Instrument should indicate approx. 0 ohm.
if reading is correct:
^ Proceed to step A2 "Checking signal ground lead". It reading is incorrect:
^ Check lead between OBD II DLC terminal 4 and ground terminal at A-post on passenger side (31/15) for open-circuit as per [LA2].
^ Proceed to step A2 "Checking signal ground lead".
A2
CHECKING SIGNAL GROUND LEAD
- Switch off ignition
- Connect ohmmeter between OBD II DLC terminal 5 and cigarette lighter ground.
Instrument should indicate approx. 0 ohm.
If reading is correct:
^ Proceed to step A3 "Checking supply lead". It reading is incorrect:
^ Check lead between OBD II DLC terminal 5 and ground terminal (31/33) on engine for open-circuit as per [LA2].
Proceed to step A3 "Checking supply lead".
A3
CHECKING SUPPLY LEAD
- Switch off ignition.
- Connect voltmeter between O8D II DLC terminal 16 and cigarette lighter ground.
Instrument should indicate battery voltage.
If reading Is correct:
^ Proceed to step A6 "Checking Volvo Diagnostic communications interface".
If reading is Incorrect:
^ Proceed to step A4 "Checking fuse 15".
A4
CHECKING FUSE 15
If fuse Is intact:
^ Proceed to step AS "Checking battery supply before and after fuse".
If fuse is faulty:
^ Check circuit for short-circuit to ground as per [LA3].
^ Proceed to step A6 "Checking Volvo Diagnostic communications interface".
A5
CHECKING BATTERY SUPPLY BEFORE AND AFTER FUSE
- Switch off ignition.
- Connect voltmeter between rear terminal on fuse-holder for fuse 15 and cigarette lighter ground.
Instrument should indicate battery voltage.
If reading is correct:
^ Check lead between front terminal on fuseholder for fuse 15 and OBD DLC II unit terminal 16 for open-circuit as per [LA2].
^ Proceed to step A6 "Checking Volvo Diagnostic communications interface".
If reading Is Incorrect:
^ Check lead between fuse 15 and battery positive terminal for open-circuit as per [LA2].
^ Proceed to A6 "Checking Volvo Diagnostic communications interface".
A6
CHECKING VOLVO DIAGNOSTIC COMMUNICATIONS INTERFACE
- Switch off ignition.
Connect ohmmeter between OBD II DLC terminal 3 and cigarette lighter ground.
Instrument should indicate 10-20 kOhm.
If reading Is correct:
^ Proceed to step A7 "Checking OBD II communications interface".
If Instrument Indicates approx. 0 ohm:
^ Check leads between OBD II DLC terminal 3 and Motronic 4.3 SFI/DI engine control module (ECM) # B5, and between terminal 3 and DLC (A) terminal 2 for short-circuit to ground as per [LA3].
^ Proceed to step A7 "Checking OBD II communication Interface".
If instrument indicates infinity:
^ Check lead between OBD II DLC terminal 3 and ECM # B5 for open-circuit as per [LA2].
^ Proceed to step A7 "Checking OBD II communications interface".
A7
CHECKING OBD II COMMUNICATIONS INTERFACE
- Switch off ignition.
- Disconnect transmission control module (TCM) if installed.
Connect ohmmeter between OBD II DLC terminal 7 and cigarette lighter ground.
Instrument should indicate 90-110 kOhm.
If reading Is correct:
^ OBD II DLC is OK.
If Instrument indicates approx. 0 ohm:
^ Check leads between OBD II DLC terminal 7 and ECM # 836, and between DLC (A) terminal 6 and TCM # 822, for short-circuit to ground as per [LA3].
If instrument indicates infinity:
^ Check lead between OBD II DLC terminal 7 and ECM # 836 for open-circuit as per [LA2].
WARRANTY STATEMENT: Claims may be submitted under the New Car Limited Warranty when a manufacturing defect is present using claim type: 01
Operation No. Description Time allowance
280723 Checking OBD II data link connector 0.4 hr