The Supplemental Restraint System (SRS), commonly known as the airbag system, is a critical safety feature in your Volvo. A malfunctioning SRS is indicated by an illuminated SRS warning light on your dashboard. This light, often accompanied by an OBDII trouble code, signals a potential problem that requires immediate attention. This guide focuses on understanding, diagnosing, and addressing OBDII SRS codes in Volvo vehicles.
Understanding OBDII SRS Codes in Volvo Cars
Volvo cars, like most modern vehicles, utilize the OBDII (On-Board Diagnostics II) system to monitor and report diagnostic trouble codes (DTCs). When the SRS system detects a fault, it stores a specific code in the vehicle’s computer. Accessing these codes via the OBDII port allows you to pinpoint the issue. However, for older Volvo models (pre-1996), you might need to use a specific Volvo diagnostic tool or consult the vehicle’s service manual for SRS code retrieval. For models 1992 and later, you can often use a standard OBDII scanner.
Locating the SRS Test Point on Your Volvo
Finding the SRS test point is the first step in diagnosing the issue. The location varies depending on the model year:
- 1992+ Models: Look for two diagnostic socket boxes near the left strut tower. Box “A” typically houses the probe, test button, and LED readout lamp. The SRS test point is usually socket 5 in box “B.”
- Pre-1992 Models: The SRS test point is often located in the fuse box behind the ashtray. Look for four fuse holders on the front of the fuse box. The second from the left, with a terminal on one side only, is generally the SRS test point.
Reading and Resetting SRS Codes
Once you’ve located the test point:
- Create a Jumper Wire: Use an 18-22 gauge solid wire with 1/4 to 1/2 inch of insulation stripped from each end.
- Connect and Ground: Insert one end of the wire into the SRS test point. Ground the other end by touching it to the metal ring of the cigarette lighter.
- Turn On Ignition: Turn the ignition to the “ON” position (without starting the engine) and wait 15 seconds.
- Ground the Terminal: Briefly ground the test terminal for 2 seconds. The SRS light will flash, indicating codes (see table below).
- Resetting Codes: To reset, ground the test terminal three times for at least 0.25 seconds each within a 1.5 to 5 second window. The SRS light will signal a successful reset.
Volvo SRS Trouble Codes:
| Code | Fault | Corrective Actions |
|---|---|---|
| 1 | Fault in crash sensor | Check all electrical connections and/or replace crash sensor. |
| 2 | Fault in standby power unit or wiring | Check all electrical connections between unit and crash sensor. Replace standby power unit. Replace crash sensor. |
| 3 | Short circuit in test terminal or wiring | Check test terminal connector for short circuit. Check wiring harness and connectors. |
| 4 | Airbag assembly resistance low | Check wiring, contact reel, and connectors for short circuits. Measure resistance of contact reel. Replace airbag module. |
| 5 | Airbag assembly resistance high | Check gas generator connector. Check wiring and contact reel for open circuit. Replace airbag module. |
| 8 | Airbag or wiring shorted to battery positive | Check wiring and connectors for shorts. Check wiring and contact reel. Measure circuit resistance. Replace crash sensor. |
| 9 | Airbag assembly shorted to ground | Check for grounded gas generator wiring. Check wiring and contact reel for short to ground. Measure circuit resistance. Replace airbag module. |
| 10 | Mercury switch or seat belt tensioner fault | Ensure crash sensor is correctly installed. Replace crash sensor. Check seat belt tensioner wiring. |
| 11 | Both seat belt tensioners disconnected | Ensure both tensioners are connected. Check common wiring harness. Replace crash sensor. (780 model only. Car must be started twice to enable code 11 to be displayed.) |
Persistent SRS Light: Further Troubleshooting
If the SRS light persists after resetting the codes:
- Retry: Read and reset the codes multiple times. Sometimes, multiple attempts are necessary.
- Battery Disconnect: Disconnect the negative battery terminal for 30 minutes to allow the system to reset. Repeat this process three times.
- Professional Help: If the problem persists, consult a qualified Volvo technician for further diagnosis and repair.
Remember, a functioning SRS is crucial for your safety. Addressing any issues promptly ensures the system operates correctly in the event of a collision.
