9-3 1999

Engine Control Module



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Fig. ECM wiring schematic-900 & 9-3 models, 2.0L & 2.3L engines

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Fig. ECM power supply-900 & 9-3 models, 2.0L & 2.3L engines

Saab Trionic Electronic Control Module controls ignition timing, fuel injection and turbocharger boost pressure via a 70-pin wiring connector that connects ECM to its various input and output components. It contains a 32-bit processor to receive inputs, process data and provide outputs to continually and optimally operate the vehicle.

Power circuit 30, from maxi fuse 2 to the main relay, fuel pump relay and fuse 28, continuously powers ECM pins 1 and 48. The engine will not start and ECM will lose its memory when power circuit 30 is interrupted.

Power circuit 15, from vehicle anti-theft alarm control module, through fuse 17, supplies ECM pin 60 with power. The engine will not start unless power is supplied to ECM via circuit 15.

With ignition switch ON, ECM is activated, MIL lights up to indicate all systems are OK. ECM then waits for pulses from Crankshaft Position (CKP) sensor.

ECM is adjusted for a voltage between 8 and 16 volts during driving. When ignition is switched OFF, all sensors supplied with 5 volts are activated for 15 minutes. During this time, diagnostics can be performed with a SAAB ISAT scan tool.

ECM communicates bi-directionally with ISAT scan tool via pin 33.

Removal & Installation

Before replacing ECM, ensure all diagnostic tests have been performed. Recheck all grounds and power sources to ECM. Recheck all electronic components.

An ECM may be damaged by electrostatic discharges or output shorting. Your hands can carry electrostatic charges from normal actions such as sliding out of a fabric-covered seat, shuffling your feet across a carpeted floor, touching your clothing or hair, or touching another person. Exercise caution when handling ECM to avoid transmitting an electrostatic charge to it. Never touch ECM connector pins. Ground new ECM packaging to vehicle body before unpacking new ECM. Ground yourself and avoid wearing insulating rubber-soled shoes or synthetic material clothing.

If Automatic Performance Control (APC) valve winding has been short circuited, the ECM is likely also damaged. To avoid replacing APC valves repeatedly, when an APC valve winding has been shorted, replace the valve and the ECM.

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Fig. Removing ECM after removing glove box-900 & 9-3 models, 2.0L & 2.3L engines

  1. With ignition switch OFF, remove glove box.
  3. Fold back carpeting and remove central locking system relay.
  5. Disconnect ECM electrical connector and carefully remove ECM.

To install:

  1. Reverse removal procedure.
  3. To reset vehicle immobilizer, connect ISAT or appropriate scan tool. Turn ignition switch ON.
  5. Select -Body-, then select -Twice-, and then select -Immobilizing-.
  7. After 10 seconds, immobilizer will be programmed.


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Fig. ECM wiring schematic with connector pin identification-900 & 9-3 models, 2.0L & 2.3L engines

If ECM program memory ROM or working memory RAM is defective, DTC P0605 will be set. Follow all diagnostic tests before replacing ECM with a known good ECM. Check for reoccurrence of faults.