The Ignition Discharge Module (IDM), also known as the Direct Ignition Cassette or DIC, is a common failure on both NG900 and early 9-3 models. Typical life is 30-100k miles. Common faults include leaks from oil filled coils, a cracked relay housing, or burned out electrical components. Some 9-3 and 9-5 ignition modules have been recalled doe to a design defect and replaced free of charge by Saab.
The module cannot be repaired, only replaced. Installing a new one takes only about 15 minutes. Saab recommends that anytime the ignition module is being replaced with a new one, new spark plugs should also be installed, and the ecu reset by disconnecting the battery, and allowed to re-adapt to the new parts.
- T-30 bit or driver
- Dielectric grease
- Loctite, blue, only if needed
- 1994-98 T5
- Original: #9178955
- Replacement: #55561132
The ignition module is held down by four T-30 screws. If the screws are found to be loose, they may have to be reassembled with lock washers or blue Loctite.
The connector has a locking latch (red) which slides to the side, then the connector can be unplugged fairly easily.
Once the screws are out and the module is disconnected, it can be pulled straight up and removed. If possible, it should be set aside carefully, with the rubber boots which fit over the spark plugs pointing down. The module can be inspected but not tested or repaired.
Upper section with four coils, and a few other visible components. Lower section with rubber boots which go over the spark plugs, and spring contacts inside which have the same function as spark plug wires.
The revision and date of manufacture are printed on the IDM label. I this case, 1999 week 20, revision TK3.2E. The date code indicates the rough age of the cassette, which allows the mileage to be estimated. Most ignition cassettes do not last over 100k miles.
Spark Plug Boots
Before reassembly, the plugs and/or the end of the rubber boots should be coated with a thin layer of dielectric grease.
Seat the module over the plugs carefully, then press down to fit the boots on the plugs. Tighten the screws to about 8 lb-ft, and replace the connector. Check the screws a few days later to make sure they are still tight. If loose, reassemble with blue Loctite or lock washers.