Air Bag System Testing

Overview

This procedure is tailored for testing the airbag system on the Porsche 944 S / S2 with its 16v M44/41 engine, produced from 1989 to 1991. The S / S2’s airbag system includes a control unit, front sensors, and dual airbags, with a built-in diagnostics feature that monitors itself continuously. If a fault occurs, the “Airbag” warning light on your dashboard will signal it. This guide helps you use a simple test rig to read fault codes, identify issues, and fix them. A properly functioning airbag system is critical for safety in your S / S2.

Pink and blue text represents links to additional resources, tools, parts, and partner websites.

Tools Required

• Improvised Test Rig (see Air Bag Warning Light Reset for how to make it)
• Pen and paper for recording fault codes
• Ohmmeter (multimeter capable of measuring resistance)

Parts Required

Parts depend on the fault identified. Common replacements for the 944 S2 include:

• Front Sensor Left – 944 606 101 00
• Front Sensor Right – 944 606 102 00
• Airbag Unit (Driver’s) – 944 803 931 00
• Airbag Unit (Passenger’s) – 944 803 932 00
• Contact Unit – 944 652 101 00
• Control Unit – 944 618 211 00

Required Additional Procedures

Steps in these procedures are required to complete this process:

• Air Bag Warning Light Reset

Step-by-Step Procedure

Step 1: Prepare the Test Rig and Vehicle

1. Turn the ignition switch off to power down the S / S2’s airbag system.
2. Connect your improvised test rig from the airbag Molex test connector (near the fuse box in the S / S2) to a solid ground point on the chassis.
3. Press and hold the switch or pushbutton on your test rig.

Step 2: Start the Test

4. Turn the ignition switch on while holding the test rig button.
5. Wait 3 seconds after turning on the ignition, then release the button.
6. Observe the “Airbag” light on the S / S2’s dashboard. It will stay lit for 5 seconds as a self-test, then blink to display fault codes. Keep the ignition on for at least 2 minutes to capture all codes.

Step 3: Record the Fault Codes

7. Count the “Airbag” light blinks and note them down. The pattern works like this:
8. 1 to 4 flashes for the fault code group (e.g., 2 flashes = Group 2).
9. After a 3-second pause, 1 to 4 flashes for the line in the fault table.
10. After another 3-second pause, 1 to 4 flashes for the column.
11. After a final 3-second pause, 1 or 2 flashes: 1 = short-term fault, 2 = long-term fault.
12. If more faults exist, the sequence repeats after a 3-second pause. The light stays on when finished.

Step 4: Identify the Faults

13. Match your blink codes to the S / S2 fault table below:

Note: For the S / S2, Ignition Pill Circuit 1 is the driver’s airbag; Circuits 2 and 3 are the passenger’s airbag.

Step 5: Fix the Faults

14. Address faults based on your codes:
15. Faults 01-06: Replace the left (944 606 101 00) or right (944 606 102 00) front sensor.
16. Faults 07-0E: Test the sensor with an ohmmeter (terminals 1-2: 10 kOhm; 2-3: 0 Ohm). If correct, reset the warning light (see Air Bag Warning Light Reset). If the fault remains, replace the control unit (944 618 211 00). If incorrect, replace the sensor.
17. Faults 11-12: Check sensor plug tightness. Test with an ohmmeter. If infinite resistance, replace the sensor. If correct, replace the control unit.
18. Faults 13-14: Test sensor with an ohmmeter. If okay, replace the control unit.
19. Faults 17-1A: Replace the control unit.
20. Faults 1B, 1E, 21, 24: Install a new contact unit (944 652 101 00), reset, and test. If persistent, try a new driver’s airbag unit (944 803 931 00), reset, and test. If still present, replace the control unit.
21. Faults 1C, 1D, 1F, 20, 22, 23, 25, 26: Install a new passenger’s airbag unit (944 803 932 00), reset, and test. If persistent, replace the control unit.
22. Fault 27: Check airbag and contact unit plugs. If tight, try a new contact unit, reset, and test. If persistent, try a new driver’s airbag unit, reset, and test. If still present, replace the control unit.
23. Faults 28-29: Check airbag plug. If tight, try a new passenger’s airbag unit, reset, and test. If persistent, replace the control unit.
24. Faults 2A-2C: Install a new airbag unit (driver or passenger as indicated), reset, and test. If persistent, replace the control unit.
25. Fault 2D: Replace the contact unit. Check plug contacts for corrosion. If okay, try a new driver’s airbag unit, reset, and test. If persistent, replace the control unit.
26. Faults 2E-2F: Check plug contacts for corrosion. If okay, try a new passenger’s airbag unit, reset, and test. If persistent, replace the control unit.
27. Faults 30-31: If the lamp stays on, replace it. Check wiring. Replace the control unit if needed.
28. Fault 32: Replace the control unit.
29. Faults 33-34: Post-accident codes. Replace all components (sensors, airbags, control unit).

Step 6: Reset the System

30. After repairs, reset the airbag warning light (see –Air Bag Warning Light Reset-).
31. Repeat the test to confirm no faults remain.

Post Procedure Checklist

• Turn the ignition on; “Airbag” light should light for 5 seconds, then go off.
• Verify no new fault codes after resetting.
• Check all plug connections for tightness and no corrosion.

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manual, Volume 1
• Youtube