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Home >> Saab >> 1994 >> 900 Turbo Convertible L4-1985cc 2.0L DOHC Turbo EFI >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> B Code Charts >> B1302

B1302





Fault Symptom
TCS OFF lamp on, TCS system inoperative

Condition
For trouble code B1302: Control module output pin 3 shorted to ground or no continuity. Alternatively, control module input pin 27 shorted to ground.
For trouble code B1303: Control module output pin 20 shorted to B+ or no continuity. Alternatively, control module input pin 27 shorted to B+.

NOTE: B1302 and B1303 can be generated in connection with fault diagnosis when wiring to the throttle body is disconnected and the ignition switch is turned to the Drive position.

Diagnostic Procedure
1. Connect an ISAT (scan tool) and select "TCS THROTTLE POS" in the "OBTAIN READINGS" menu. Drive the car at >4 km/h. On releasing the accelerator the ISAT (scan tool) should show a reading of about 20%. This should then successively rise to 70-92% at full throttle. (Note that the TCS throttle opens fully at speeds <4 km/h.)
If the readings are correct, clear the trouble code, drive the car on the road and check whether the trouble code is generated afresh.
If the readings are incorrect or if the trouble code is generated afresh, proceed with point 2.
2. Switch off the ignition.
Unplug connector H16-2 and measure the resistance in the TCS throttle position sensor across pins 9 and 11 of the female connector.
- The correct resistance is approximate. 1000-1200 ohms.
Also measure the resistance across pins 9 and 10 of the female connector while slowly closing the throttle butterfly by hand. The resistance should now rise smoothly from about 100-300 ohms to about 800-1200 ohms.
Also check that the resistance across pin 9 and a good ground is infinite (OL).
If the resistance is OK, the fault lies between connector H16-2 and the control module. Continue with point 4.
If it is not, the fault lies between connector H16-2 and the throttle body or in the throttle body. Proceed to point 3.





3. Remove the TCS throttle body.
Carry out checking as described in point 2 above, directly on throttle body pins 2, 3 and 4.
If the measurements produce correct readings, remedy the defective wiring between the throttle body and connector H16-2.
Should the measurements produce incorrect readings, on the other hand, install a replacement TCS throttle body.
4. Turn the ignition switch to the drive position. Measure the voltage across pin 9 of the male connector (H16-2) and B negative (-).
- The correct voltage is about 5 V.
Also check that pin 11 of the male connector is correctly grounded by measuring the voltage to B positive (+).
- The correct voltage is battery +.
If the readings are correct, the supply from control module output pins 3 and 20 is correct and the fault lies between pin 27 of the control module and pin 10 of the male connector (H16-2). Continue with point 5.
If the readings are incorrect, the fault lies between pin 20 of the control module and pin 11 of the male connector or between pin 3 of the control module and pin 9 of the male connector. Proceed to joint 6.





5. Switch off the ignition
Remove the right-hand front seat, withdraw the TCS control module and plug in a BOB.
With the ignition switch in the drive position, check the cable for the input from the TCS throttle butterfly's position sensor by measuring the voltage across pins 27 and 13 of the TCS control module.
- The correct voltage is about 4.4 V.
If this is not obtained, remedy the cable between pin 27 of the control module and pin 10 of the male connector (H16-2).
6. Switch off the ignition.
Remove the right-hand front seat, withdraw the TCS control module and plug the BOB into the control module connector (control module disconnected).
Check the cable between pin 3 of the control module and pin 9 of the male connector (H16-2) and also the cable between pin 20 of the control module and pin 11 of the male connector for continuity/shorting.
Remedy any defective wiring.
Plug in connector H16-2, connect the control module and turn the ignition switch to the Drive position. Check that the control module is correctly grounded on pin 20 by measuring the voltage across pins 20 and 32.
- Correct voltage is battery +.
Also check that there is a voltage of about 5 V on pin 3 of the control module by measuring the voltage across pins 3 and 13.
7. Clear the trouble codes. Start the car and drive it to check whether the trouble code is generated afresh.
- If it is then see preliminary diagnostic information.

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