Check Output Signal For ECM

Measure the voltage between ECM connector and chassis ground.

Connector & terminal 

(B135) No. 3 (+) - Chassis ground (- ): 

Is the voltage more than 4.5 V? 

YES. Go to  CHECK INPUT SIGNAL FOR ECM  . 

NO. Go to  CHECK OUTPUT SIGNAL FOR ECM  . 

Measure the voltage between ECM connector and chassis ground.

Connector & terminal 

(B135) No. 3 (+) - Chassis ground (- ): 

Does the voltage change by shaking the ECM harness and connector? 

YES 

Repair poor contact in ECM connector.

NO 

Contact Saab.