Diagnosing Ignition Discharge Module (IDM) (01/94-0422)

WARNING: This page is about the 9000 CD, 2.3 B, Automatic, which is a different variant/trim than selected.

Publication date: 1994-01-01
Reference number: 01/94-0422

DIAGNOSING IGNITION DISCHARGE MODULE (IDM)

TECHNICAL SERVICE BULLETIN

Reference Number(s): 01/94-0422, Date of Issue: January 1994

DIAGNOSING IGNITION DISCHARGE MODULE (IDM)

APPLICATION

Model(s): Saab 9000 Models With DI/TRIONIC

Category: Electrical

Section: 3

Page: 66

Bulletin No: 01/94-0422

Code: 340

Date: January 1994

SERVICE INFORMATION

A set of test spark plugs shown in Fig 1 , has been developed to facilitate checking the operation of the ignition discharge module (IDM). Due to the wide electrode gap these spark plugs have, the IDM operates under optimal load so that any faults can be discovered more easily.

Fig 1: Test Spark Plugs For IDM

CARS AFFECTED

9000 models equipped with DI/TRIONIC

PARTS INFORMATION

Description	Part No.
Test Spark Plugs	86 11 386 *
Ground Cable	86 10 867

ACTION

If the IDM is suspected of being faulty, the following procedure can be recommended:

Remove the IDM from the cylinder head.
Fit all test spark plugs in the ignition discharge module.
Connect ground cable 86 10 867 between all the spark plugs and a good ground.
Invert the IDM (spark plugs pointing downwards), making sure all the electrodes are at a safe distance from conducting material (ground).
NOTE: The ignition discharge module must be positioned with the spark plugs pointing downwards to ensure that the oil in the coils provides satisfactory insulation in the high-tension windings.
Remove fuel pump fuse (#14). See Fig 2 .

Fig 2: Removing Fuel Pump Fuse #14
Run the starter motor briefly and check that:
- sparks are produced on all spark plugs
- no flashover occurs in the discharge module cover

WARNING: Take great care. The ignition system operates at high voltage. Do not under any circumstance touch the ignition discharge module while the starter motor is engaged and during the burn-off phase after the ignition has been switched off. The high voltage generated may be fatal to persons with a weak heart and those having a pacemaker.

IGNITION DISCHARGE MODULE WITH REPLACEABLE COILS-M92

If the IDM is of an earlier type with replaceable coils, check them as described in PSI 04/91-0101 (Sec. 3, Page 9).

When a discharge module of earlier type is ordered, an IDM of new design will be supplied together with a special adapter wiring harness.