Hi Scotty,
Spent a little more money on an Innova 6100P scanner to get ABS codes for my 2005 Pontiac Vibe AWD with 114K miles. The ABS and tire pressure indicators have been coming on randomly over for nearly a year despite tire pressure being spot on and no issues with brakes (front calipers/rotors/pads replaced three months ago due to leaking fluid and excessive rotor warping). When I plugged my new scanner in I got two ABS codes and one for the airbag system (the Takata airbags were replaced some time ago):
C1241 - ECU Voltage
C1249 - Stop Lamp Switch Circuit Open
B1660 - Passenger Airbag Disabled Indicator Circuit Malfunction
The "possible fixes" listed are to inspect the battery and charging system, and the tire pressure, but the battery and alternator are new (tested with both scanner and multimeter) and I check tire pressure once a week. Living in upstate NY I'm concerned that these codes could cause me to fail my upcoming inspection, but there seems to be very little information on how to fix these issues or if they can be fixed at all. Please help.
Heres the skinny on the air pressure system on the Vibe. Your vehicle does NOT have TPMS sensors inside the tires. The ABS system detects speed of each wheel relative to others to determine if a tire is low or not. ABS compares the speed value and when one tire is detected faster in speed...because it has a smaller diameter..it tags it as a tire with low air. So i'm thinking..there is a problem with the ABS unit and not your tires.
Reference material: https://forums.genvibe.com/phpBB3/viewtopic.php?t=44975
Thanks for the response. You're correct, the Vibe uses "indirect" ABS. The problem is that my little computer can't tell me which one(s) throws the code. Maybe run some tests with my multimeter? If you have a suggestion that doesn't involve dropping a few hundred bucks at Rock Auto I'm all ears. 😉
yeah..Now to check the ABS ECU we would have to proble with the DVOM what the ECU sees signal wise from each wheel. I see some systems have two wires and some three...that complicated things...!! but essentially it would be nice to have four DVOMs and proble the signal and then drive the vehicle and see what the signal differences reveal....Now reading ABS faults on Picotech.com reveals how some of these fascinating faults occur and yet the ABS ECU doesn't report it....But you probably know that repair tech is not going to screw with this and recommend a NEW ABS ECU to SEE if it works then go from there LOL!
Another angle of attack is to check the resistance between the ABS sensor and the ABS ECU plug in all four of them and each and every wire. usually the fronts are suspect because of the tire turning...its like the power door locks work/ don't work but no one checks the wires going from the body to the door as those wires were being bent since day one...till they broke.. now Anyways....thats all I gots....
There's a few things you can verify.
Check the supply voltage right on the ECU (not sure which one it means... PCM or brake ecu?).
You might have a fault in the wiring or connections.
Then check the wheel sensors. They should have a characteristic resistance that you can check online. And they should output an alternating square wave signal as you rotate the wheel. If you can then make sure the reluctor ring is clean. Some times bad bearings can cause erroneous readings too.
And the last code ... does the disabled airbag light come on? If not, then you would need to see what's going on inside the dash.
