I've started another thread, because, although I mentioned it in a previous one, it was more of a "rant" about car washes, and has turned into a humorous thread to this effect, so I'd like to use this one to discuss the fault / diagnosis, if that's ok. Cheeky, I know, being an Omega forum, but there are some clever folk on here
The Car
2010 Mondeo Zetec TDCi 140 Estate, 6 speed. 70k ish from new. Owned by my family for most of it's life.
I've driven the car for a year with no issues at all and thoroughly enjoyed it. The other day I took it to a hand car wash, and, immediately after I drove away, the airbag light was on. I thought maybe they'd rammed the hoover into a connector under the seats and upset the SRS system etc.
I took the car to the local garage on the way home, who pulled out the fault code B0001 - Driver Frontal Stage 1 Deployment Control - Circuit Resistence below threshold.
They told me that "the airbag in the wheel needs changing mate". I didn't believe them, so decided best bet would be diagnose myself.
After reading online, and a trip to Maplin I soldered a switch into my ELM327 reader to enable me to read the Medium Speed CAN Bus and talk to the RCM (Restraint control module, AKA Airbag ECU) - and got a copy of some software that talks to Fords. So I can now read codes, reset them, and get all manner of live data. It's pretty cool.
Anyhow, I reset the codes, and the above code came back. I then looked at the live data. All of the airbags were reporting a 3ohm resistence (correct) apart from the drivers airbag, which was reporting a resistence of 1ohm. At this point, I thought maybe the garage were correct, and decided to remove the driver airbag to test the resistence myself. As I had the airbag half out of the wheel (but not disconnected) I had to start the engine to move the wheel, and noticed that the fault light had gone out, with the airbag half way out. When I put it back in, the fault came straight back.
Anyhow, I removed the airbag, and after removing the little shorting bar, I got a 3 ohm resistence with my meter, proving the airbag is GOOD and the fault lies elsewhere.
I installed a 3 ohm resistor in it's place, but despite doing so, the live data still showed a 1 ohm resistence. Then interestingly I read the data with nothing connected in place of the driver airbag, and, got the same 1 ohm reading.
To cut a long story short, with either a 3 ohm resistor or the airbag connected, when I press HARD on the clock spring behind the steering wheel (the bit with electronics in, that turns) the fault goes away, and it shows a 3 ohm resistence. Let go, and, back to 1 ohm.
So the issue appears to be the clock spring.
Would folk concur?
Can this be taken apart and the connections checked / soldered, or is it goosed? They are very costly new, and second hand parts of this nature after being beaten off by some Neanderthal breakers yard might not be a great call.
I'm pleased I persevered with it, because the garage would have charged me for a new airbag I didn't need. I really should get some of my confidence back, I'd have never considered going near a garage in the past
Interestingly not sure how a car wash would have damaged the squib. Unless they sprayed a LOT of fluid around. I guess could just be a co-incidence, that the mondeo electrics reared their head at this stage!
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Topic: MK4 Mondeo Airbag issue (Read 5267 times)