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The airbag light and DIC warning (Service Airbag) came on for my wife when she started the 2007 Envoy today. ( I was sad that I didn't see the DIC message but that's another story).
At home, I tried it and there was no warning so I checked the codes with Tech2Win and my VCX-FD interface and it had no current codes but three that would have caused the Airbag warning. It listed these in order of priority: B1000, B0042 and B0014.
The first one is not even mentioned in GMs online (https://gm.saturn.team/) diagnostic codes for SRS module. However, the description in Tech2Win does indicate this is a malfunction in the module. I have researched and found that it doesn't necessarily mean the module is faulty, but at that time it was confused somehow and so set the B1000 code. The other codes are both connected with incorrect voltage/resistance measurements at the start-up diagnostic test.
InTech2Win I saw that the SDM module battery voltage was showing only 9.44V! (with engine off but Ignition ON). With engine running it did increase to 11.1V. BUT all other modules show about 14V with engine running, due to the alternator output, and with engine stopped they still show about 12.5V.
So the low voltage to the SDM module must be the problem. I can see that a low voltage would upset the module and cause the B1000, and a dodgy operation of the SDM could cause bad voltages/resistances in the airbag loops and so cause the other two codes.
Has anyone had this before?
Things done so far:
1. I removed the centre console and disconnected the battery for a few minutes before disconnecting the SDM plug. I couldn't see anything wrong. This is a very different plug to the normal connectors; the wires are protected by a semi-clear plastic cover. I removed that by prying up one end that seemed to have clips and then sliding it off. You can't see the terminals though. The wires disappear through small holes. All I could do is gently wiggle and pull on them to see if any wire pulled out. They didn't.
I can't even check continuity from there because the terminals are not accessible. It's probably done that way to prevent someone inadvertently firing an airbag by connecting the small voltage of a test meter.
2. While I had the battery disconnected, I also pulled the airbag fuse and checked continuity - good. I plugged and pulled it several times to scrape any oxidation or contaminants off.
3. Checked resistance between the battery negative post and G102 (I spotted this just behind the battery) . Very low- around 0.1 ohms which is likely due to the test leads.
I reconnected the battery and checked again. SRS module still shows only 9.4V battery voltage. I measured the voltage on both sides of the airbag fuse - the same at 12V (with ignition off).
What do you think? a bad splice in the ground path? The service manuals show the SDM ground goes through S202 before going to G102. S202 is above the driver's knee panel, so I would have to remove all that and probably undo the harness wrap to find S202.
I suppose I could disconnect both airbags and the seatbelt pre-tensioners, to prevent firing, then check continuity and resistance from the SDM plug. Oh, drat, I forgot, the terminals still are not accessible. It looked like the slim mating slots of the connector face were blocked (perhaps by a safety cover) but maybe I was wrong; maybe I can push a thin wire of some sort into the slots to reach the terminals on the mating surface.
Are you all sure you haven't seen this problem before? I'd love an instant fix
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AH- I just realised the ignition voltage from the airbag fuse goes through a splice S220. I haven't checked that yet. That splice also goes to the Rollover sensor connector. My rollover connector is unused but is there, so I could check the voltage there. ALSO, that connector's ground goes to the same splice S202 as the SDM plug.
OK, I'll check those next.
Although, if anyone knows this problem and the culprit, please chime in.
At home, I tried it and there was no warning so I checked the codes with Tech2Win and my VCX-FD interface and it had no current codes but three that would have caused the Airbag warning. It listed these in order of priority: B1000, B0042 and B0014.
The first one is not even mentioned in GMs online (https://gm.saturn.team/) diagnostic codes for SRS module. However, the description in Tech2Win does indicate this is a malfunction in the module. I have researched and found that it doesn't necessarily mean the module is faulty, but at that time it was confused somehow and so set the B1000 code. The other codes are both connected with incorrect voltage/resistance measurements at the start-up diagnostic test.
InTech2Win I saw that the SDM module battery voltage was showing only 9.44V! (with engine off but Ignition ON). With engine running it did increase to 11.1V. BUT all other modules show about 14V with engine running, due to the alternator output, and with engine stopped they still show about 12.5V.
So the low voltage to the SDM module must be the problem. I can see that a low voltage would upset the module and cause the B1000, and a dodgy operation of the SDM could cause bad voltages/resistances in the airbag loops and so cause the other two codes.
Has anyone had this before?
Things done so far:
1. I removed the centre console and disconnected the battery for a few minutes before disconnecting the SDM plug. I couldn't see anything wrong. This is a very different plug to the normal connectors; the wires are protected by a semi-clear plastic cover. I removed that by prying up one end that seemed to have clips and then sliding it off. You can't see the terminals though. The wires disappear through small holes. All I could do is gently wiggle and pull on them to see if any wire pulled out. They didn't.
I can't even check continuity from there because the terminals are not accessible. It's probably done that way to prevent someone inadvertently firing an airbag by connecting the small voltage of a test meter.
2. While I had the battery disconnected, I also pulled the airbag fuse and checked continuity - good. I plugged and pulled it several times to scrape any oxidation or contaminants off.
3. Checked resistance between the battery negative post and G102 (I spotted this just behind the battery) . Very low- around 0.1 ohms which is likely due to the test leads.
I reconnected the battery and checked again. SRS module still shows only 9.4V battery voltage. I measured the voltage on both sides of the airbag fuse - the same at 12V (with ignition off).
What do you think? a bad splice in the ground path? The service manuals show the SDM ground goes through S202 before going to G102. S202 is above the driver's knee panel, so I would have to remove all that and probably undo the harness wrap to find S202.
I suppose I could disconnect both airbags and the seatbelt pre-tensioners, to prevent firing, then check continuity and resistance from the SDM plug. Oh, drat, I forgot, the terminals still are not accessible. It looked like the slim mating slots of the connector face were blocked (perhaps by a safety cover) but maybe I was wrong; maybe I can push a thin wire of some sort into the slots to reach the terminals on the mating surface.
Are you all sure you haven't seen this problem before? I'd love an instant fix
---------
AH- I just realised the ignition voltage from the airbag fuse goes through a splice S220. I haven't checked that yet. That splice also goes to the Rollover sensor connector. My rollover connector is unused but is there, so I could check the voltage there. ALSO, that connector's ground goes to the same splice S202 as the SDM plug.
OK, I'll check those next.
Although, if anyone knows this problem and the culprit, please chime in.
