So I have been chasing this issue that I have had for a while with my ABS ASC lights being on and having a check engine light with a P1774 code stored. The scanner I use (Can-Tech) shows no engine codes but does show the P1774 under the transmission section. I just managed to get round to doing an in depth diagnositc and have come to the conclusion that the issue is with the ABS control module. I should mention that my research showed that 1774 is for the left rear wheel speed sensor. I have already changed it which led me down the diagnostic path. Anyway, in order to make my determination I disconnected the ABS control unit and checked both wires going to the sensor with the sensor also disconnected. I did not find any shorts to ground or break in the wires. I should mention that I also checked the reference voltage going to the sensor with the control module connected and found it to be 1.5V which compared to the right side sensor was off by at least 10V. This initially led me to believe that I was dealing with a short to ground.

In the midst of all this the annual inspection became due and I decided to take it in even though the MIL light was on. My reasoning being that an ABS fault should not be grounds to fail an emissions inspection. Well, guess what, the inspection showed up the same DTC P1774 but did not deem it to be an ABS fault and failed the test. It was listed as a generic fault code with no further description.

So I am wondering if anyone else has been down this path and if so did you find a solution. The nearest Mini dealer is in Rochester which is about 2 hours from here in Syracuse. Notwithstanding the fact that I really don't want to pay their shop rates.

Thanks in advance for any help you guys can offer.

 

That is correct - P1774 indicates your Mini's rear wheel speed sensor lost its signal. It could be the sensor itself, but more likely, it is either the wiring is damaged (check for continuity), or the ABS gears on the wheel bearing assembly have gotten gummed up with dirt and debris which is preventing the magnetic sensor from detecting their movement.

Most state inspection stations will not bother differentiating error codes, and will just fail you. Fix the issue, reset the lights, then go to get inspected and you will pass.

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[QUOTE=afadeev;4056654]That is correct - P1774 indicates your Mini's rear wheel speed sensor lost its signal. It could be the sensor itself, but more likely, it is either the wiring is damaged (check for continuity), or the ABS gears on the wheel bearing assembly have gotten gummed up with dirt and debris which is preventing the magnetic sensor from detecting their movement.


I have pretty much determined that the issue lies with the ABC/DSC control unit. I have ordered a used unit and should have it by the end of this week. This should take care of the wheel sensor code P1774 but does not explain why the car would fail the emissions test.


While I'm on the subject, has anyone else had the opportunity to replace the ABS pump/control unit and if so how much fun was it?

 

So, as I mentioned in my earlier post I replaced the ABS control unit with a used one but still had the code. I also noticed that the ABS did not work whereas it still functioned even though I had the issue with the left rear with the old unit. Turns out that I needed to have it coded to the car. I also still had the hard code and could not clear it. So I took it to a local shop Upstate Imports in Baldwinsville, NY who I can highly recommend to anyone in the CNY area. They were able to code and calibrate the unit to the car but unable to clear the code. I went through my diagnosis and repairs to date with the owner Jeff and he deduced that I had a wiring problem. Not what I wanted to hear but he did say that it would most likely be in the area where the wires enter the vehicle. He was also kind enough to print off some voltage and resistance specs that I could use to properly check the circuits.


So I took the car home and pulled out my meter and started at the left rear where the ABS sensor connects to the body harness. The specified reference voltage is 8V measured across the blue and the brown wires. There are a couple of access points on the harness side connector where you can probe the terminals. The first reading I got was similar to what I was getting previously 1.5 to 2.0V. However, I did notice that it fluctuated if I moved the connector around a bit. I took a number of readings and took my meter off auto and determined that it was indeed fluctuating. I then took a close look at the wiring between the connector and the grommet where it passes through to the inside. I eventually found a spot on the blue wire that looked as though it was pinched. When I unraveled the tape from around the wires and took a moved the wire at the pinch point it pretty much came apart.


So, eureka, I found it. I repaired the wire using solder of course and shrink wrapped and taped it back up. I hooked up my scan tool and was even more elated when I found that I was able to clear the code. So, if anyone else runs into this or a similar issue I would highly recommend checking the wiring as part of any diagnosis you may do, it can mean the difference in spending a bunch of money on unrequired sensors and as in my case a control unit for the sake of a few cents worth of shrink wrap and insulating tape.