Edits and Additions (Read here for recently updated information):
2012/11/06: Updated airbag code table with supplemental information from 1990-1991 Porsche 911, 924 and 944 series cars.
2012/05/15: Added scans of the official VW factory microfiche, section 68 (Cabriolet with airbag).
2011/11/12: Added more codes obtained from the official VW Repair Manual Microfiche.
2011/10/26: Adde partial trouble code list added, edited instructions to reflect recently obtained information.
2010/10/15: Added link to the jumper-only code reset procedure courtesy of Dave (redcorradoguy).
There have been some talks in the forum about the code read and warning light reset procedure for the airbag system equipped in the 1990-1993 VW Cabriolet. This thread contains instruction to read and reset airbag code and turn off warning lights.
Quick history recap:
The Federal Motor Vehicle Safety Standard 208 in the United States “require cars produced after April 1st 1989 to be equipped with a passive restraint for the driver.” VW met this requirement for the Cabriolet model by implementing a Siemens-based airbag system. An automatic seat belt would also meet the passive restraint requirement, but the owners of cars with automatic seat belts can vouch its awkwardness and inconvenience.
According to the VW service literature I have, the airbag system won’t deploy if any one of the two red airbag warning lights in the instrument cluster is illuminated.
The official VW tech literature, Tech Talk video # 225, and the Bentley service manual calls for the use VAG 1551 diagnostic tester and the factory service microfiche / microfilm.
VAG 1551, despite being old and outdated, is hard to find and expensive to buy.
VAG-COM / VCDS does not communicate with the airbag controller. Ross-Tech noted the incompatibility in their VW Issues & Problem page.
The only 3rd party product I found that has direct mention of being compatible with the VW Cabriolet airbag controller is the old VWTool / VDS-Pro software.
This thread will mostly deal with the use of the VWTool software to read and erase the airbag fault codes.
Here are the parts of the airbag system we will be dealing with:
The airbag diagnostic connector:
Airbag warning lights:
Why are the lights on?
The left readiness indicator illuminates to indicate the system is not ready to deploy. The system may be in the process of charging the energy reserve capacitor (which takes about 5 seconds to complete), disabled due to stored fault code, or it’s in the process of communicating with the scan tool. It is also used for the blink code output.
Left light on = system not ready.
The right fault indicator illuminates to indicate there is / are trouble code(s) detected by the airbag controller. Most common reason that triggers this LED is due to component removal where the ignition switch is turned on without having the airbag module connected. On the similar Porsche 924 airbag system, the light is often triggered by low battery charge and the subsequent starting / jump starting attempts.
Right light on = system detected a fault.
Code-read and light-reset procedure:
What I used:
- A generic serial* VAG-COM compatible OBD-II KKL cable
- VW/Audi 2x2 “OBD-I” adapter
- A PC with a real serial / 9-pin RS-232 port, running Windows (I used Windows XP). Note that USB to serial adapters, like the one built into the FTDI-based USB VAG-COM cable I own, does not work* with the airbag controller.
- VWTool / VDS-Pro software. I’m using an old version, version 2.0.9 (EDIT: Website appears to be defunct as of 2011/10/26. Google is your friend)
*Addition (2010/12/7): I had the setup working with a generic USB VAG-COM cable, but it seems to be more finicky than the serial cable. VWTools can be run within Windows XP Mode under Windows 7 64-bit (Professional and up), although there seems to be periodic loss in communication to the airbag controller (but will re-establish communication after a few seconds).
Prepare the computer:
Connect the DB9 connector of the VAG-COM cable to a serial port on the computer.
Install the VWTools software, configure the software to use the correct COM Port number, corresponding to the physical serial connector the VAG-COM cable is connected to. On serial port-equipped PCs, the ports are normally assigned to COM1 through COM3 and can be verified or reassigned in the XP device manager window.
Connect the cables to the car:
Lift up the shift boot / shift plate to reveal the diagnostic connectors. Federal-emission cars will have a black and a red connector, while the California-emission cars will have an additional white connector for the Digifant-I engine control unit.
Connect the black plug to the black connector. This supplies power to the VAG-COM cable.
Connect the white plug to the red connector. This is the communication line to the airbag controller.
Connect the 2x2 adapter cable to the serial VAG-COM cable. The indicator light on the VAG-COM cable should now be lit.
Performing code read:
Turn the ignition switch to the on position. No need to start the car. You should see the two lit airbag warning lights in the instrument cluster.
Launch the VWTool software.
Click on the yellow “Audi-VW Tool Version 2.0.9” text. “Manual Address Entry” window should appear.
In the address box, type in 57, then click Send Address.
If the communication between the PC and the car is established, a “Receiving Data” text in blue should be blinking, and the airbag controller information will show in the yellow boxes.
Click on Fault Codes.
A list of fault codes should be listed in a window.
Addition (2011/10/26): Make a note of your codes and compare them with the code list near the end of this post.
If your code is not listed, lease take a note of this code and its descriptions, if available. Reply to this thread with your unknown codes.
Performing code erase:
Click Erase Error Codes button, and confirm code erasure in the next window. The right airbag warning light should turn off.
Turn off the ignition and turn it back on. If the right airbag warning light stays off, the reset procedure is complete.
If the light comes back on, there is likely a current fault that needs to be located and corrected. Look up the error code with the service information to aid in locating the problem. The repair procedure may be added to another thread once the official factory service information is located.
The descriptions of the airbag fault codes are mostly unknown as the system is not well-documented. Although, it is possible that the official factory service microfiches contain this information. Please contact me if you have access to the factory microfiches. (EDIT 2011/11/12: Official VW Repair Manual Microfiche located, post edited to reflect available information)
If you don’t have the cables but would like to read the codes, please refer to the (EDIT 2011/10/26) airbag page on Cabby-Info. Note: on the spare controller I'm testing on, code reset involves grounding pin 1 for about 10 seconds after reaching the end-of-code sequence; replace step 8 with "ground pin 1 for 10 seconds, disconnect jumper, then switch off the ignition."
Will these old airbag systems still deploy?
Numerous YouTube videos of rigged airbag deployments suggest the gas generator in old cars do work. A functional airbag system relies on proper gas generator operation, good connectivity between components, as well as proper sensor and controller operation. I believe if the controller is capable of detecting faults of various components and setting fault codes (other than the “airbag controller fault” error), the controller is functional and there is a good chance the airbag will deploy in a severe frontal collision.
I hope this information would be useful to fellow cabby owners
Update (2012/11/6): Partial Trouble Code List / Definitions:
With a spare airbag controller, associated components, plus some trial-and-error, I was able to replicate some fault conditions and record the trouble codes, both the VWTools hex code and the jumper blink code. A partial code list is included below.
Current Fault (31, h70) Stored Fault (32, hB0) Blink Code VWTool Code Blink Code VWTool Code Description (Porsche) Description (VW Cabriolet) Notes & Observations 3000 Fault memory read out complete All faults read Blinked after all other codes are displayed, blinked as 3 3111 0B_70 3211 0B_B0 Left Crash Sensor: Closed One Time Close = triggered, activated 3112 0C_70 3212 0C_B0 Left Crash Sensor: Closed Several Times 3113 0D_70 3213 0D_B0 Right Crash Sensor: Closed One Time 3114 0E_70 3214 0E_B0 Right Crash Sensor: Closed Several Times 3115 0F_70 3215 0F_B0 Left Crash Sensor: Closed 2 Seconds (2) 3116 10_70 3216 10_B0 Right Crash Sensor: Closed More Than 2 Seconds (2) 3117 11_70 3217 11_B0 Left Crash Sensor: Resistance To Voltage 3118 12_70 3218 12_B0 Right Crash Sensor: Resistance To Voltage 3119 13_70 3219 13_B0 Left Crash Sensor: Resistance To Ground 3120 14_70 3220 14_B0 Right Crash Sensor: Resistance To Ground 3121 15_70 3221 15_B0 Left Crash Sensor: Short To Voltage 3122 16_70 3222 16_B0 Right Crash Sensor: Short To Voltage 3125 19_70 3225 19_B0 Left Crash Sensor: Excessive Ground Resistance Left crash sensor not grounded Connected, but case not bolted to car body 3126 1A_70 3226 1A_B0 Right Crash Sensor: Excessive Ground Resistance Right crash sensor not grounded 3127 1B_70 3227 1B_B0 Left Crash Sensor: Open Circuit Left crash sensor disconnected 3128 1C_70 3228 1C_B0 Right Crash Sensor: Open Circuit Right crash sensor disconnected 3129 1D_70 3229 1D_B0 Left Crash Sensor: High Wire Resistance ? 3130 1E_70 3230 1E_B0 Left Crash Sensor: High Wire Resistance ? Seems to be common, blinked as 3-1-3 3133 21_70 3233 21_B0 Driver-Side Air Bag: Capacity Insufficient (3) 3135 23_70 3235 23_B0 Driver-Side Air Bag: Capacity Excessive (3) 3137 25_70 3237 25_B0 Driver-Side Air Bag: Contact Resistance To Voltage 3140 28_70 3240 28_B0 Driver-Side Air Bag: Short To Voltage Driver airbag short to 12v Blinked as 3-1-4, green wire short to 12v 3143 2B_70 3243 2B_B0 Driver-Side Air Bag: Contact Resistance To Ground 3146 2E_70 3246 2E_B0 Driver-Side Air Bag: Short To Ground Driver airbag short to ground Grounding either wire will produce trigger this code 3149 31_70 3249 31_B0 Driver-Side Air Bag: Break (3) Driver airbag disconnected Nothing connected to airbag connector 3152 34_70 3252 34_B0 Driver-Side Air Bag: Resistance Insufficient (3) Driver airbag resistance too low Airbag connector shorted with jumper 3155 37_70 3255 37_B0 Driver-Side Air Bag: Excessive Resistance (3) Driver airbag resistance too high 10 ohm resistor across airbag connector 3158 3A_70 3258 3A_B0 Warning Light: Short To Voltage Left readiness lamp short to 12v 12v into connector pin 6 3159 3B_70 3259 3B_B0 Warning Light: Break In Circuit Left readiness lamp resistance too high Burn out lamp, disconnected wiring, ignition switched on without instrument cluster connected 3160 3C_70 3260 3C_B0 Diagnosing Unit Unit Faulty (2) 3161 3D_70 3261 3D_B0 Firing Order Correct After Crash 3162 3E_70 3262 3E_B0 Ignition Current Correct After Crash 3165 41_70 3265 41_B0 Deployment After Crash 3167 43_70 3267 43_B0 Control Unit Unit Faulty Replace airbag control unit* 3168 44_70 3268 44_B0 Replace airbag control unit* 3169 45_70 3269 45_B0 Replace airbag control unit* 3170 46_70 3270 46_B0 Replace airbag control unit* 3171 47_70 3271 47_B0 Replace airbag control unit* 3172 48_70 3272 48_B0 Replace airbag control unit* 3173 49_70 3273 49_B0 Replace airbag control unit* 3174 4A_70 3274 4A_B0 Replace airbag control unit* 3175 4B_70 3275 4B_B0 Replace airbag control unit* 3176 4C_70 3276 4C_B0 Replace airbag control unit* 3177 4D_70 3277 4D_B0 Replace airbag control unit* 3178 4E_70 3278 4E_B0 Replace airbag control unit* 3181 51_70 3281 51_B0 Replace airbag control unit* 3182 52_70 3282 52_B0 Replace airbag control unit* 3183 53_70 3283 53_B0 Replace airbag control unit* 3184 54_70 3284 54_B0 Replace airbag control unit* 3185 55_70 3285 55_B0 Replace airbag control unit* 3186 56_70 3286 56_B0 Replace airbag control unit* 3187 57_70 3287 57_B0 Replace airbag control unit* 3189 59_70 3289 59_B0 Replace airbag control unit* 3190 5A_70 3290 5A_B0 Replace airbag control unit* 3192 5C_70 3292 5C_B0 Replace airbag control unit* 3193 5D_70 3293 5D_B0 Replace airbag control unit* 3194 5E_70 3294 5E_B0 ? 3195 5F_70 3295 5F_B0 Replace airbag control unit* 3196 60_70 3296 60_B0 Replace airbag control unit* 3197 61_70 3297 61_B0 Replace airbag control unit* 3198 62_70 3298 62_B0 Replace airbag control unit* 3199 63_70 3299 63_B0 Replace airbag control unit* ? 64_70 ? 64_B0 Replace airbag control unit* ? 65_70 ? 65_B0 Replace airbag control unit* ? 66_70 ? 66_B0 Replace airbag control unit* ? 67_70 ? 67_B0 Replace airbag control unit* ? 68_70 ? 68_B0 Replace airbag control unit* ? 69_70 ? 69_B0 Replace airbag control unit* 33XX ? Downtime (XX indicates amount of time since first fault occurrence) ? 3500 No faults present Footnote: * VW Microfiche info (2) Code 60 is also displayed for Code 15 or 16. Repair the cause for Code 15 or 16, erase fault memory and repeat diagnosis. (3) For additional diagnosis, see AIR BAG UNIT DIAGNOSIS. Revised 2012/11/06
*ADDITION 2011/11/12: Information obtained from the official VW Repair Manual Microfiche
- If you have blink codes that starts with "31" (VWTools codes that ends in "70"), the problem is current. Warning light will turn back on after code erase, unless the problem is corrected.
- If you have blink codes that starts with "32" (VWTools codes that ends in "B0"), the problem was previously detected and not happening at the moment. Code erase should keep the lights off.
PDF scan of the original VW factory microfiche, section 68, Cabriolet with airbag (5MB)
PDF scan of the VW Service Training Self Study Information on the Cabriolet Airbag (1.71MB)
Please visit the airbag page on Cabby-Info for a nicely illustrated blink code reset procedure.
You are responsible for your own safety. Follow all published safety procedures.
I am not guaranteeing the airbag system in your car will function as intended.
I am not responsible for any injuries or damages arising from the use of this information.
Drive defensively, don’t drink and drive, don’t text and drive.
Always buckle up.
Always backup your important data.
Fruits and vegetables are good for you.
Kammy's airbag page on Cabby-Info.
Jumper-only code reset procedure courtesy of Dave.
Old blink code read procedure post.
Federal Motor Vehicle Safety Standard 208.
Ross-Tech VW Issues & Problem page.
Description of the Porsche 944 airbag system in Automatic Occupant Protection Systems publication.
Technical information on the VW diagnostic protocol used by the VAG 1551.